The differing pathophysiologies that underlie COVID-19-associated perniosis and thrombotic retiform purpura: a case series.

BACKGROUND: There are two distinctive acral manifestations of COVID-19 embodying disparate clinical phenotypes. One is perniosis occurring in mildly symptomatic patients, typically children and young adults; the second is the thrombotic retiform purpura of critically ill adults with COVID-19. OBJECTIVES: To compare the clinical and pathological profiles of these two different cutaneous manifestations of COVID-19. METHODS: We compared the light microscopic, phenotypic, cytokine and SARS-CoV-2 protein and RNA profiles of COVID-19-associated perniosis with that of thrombotic retiform purpura in critical patients with COVID-19. RESULTS: Biopsies of COVID-19-associated perniosis exhibited vasocentric and eccrinotropic T-cell- and monocyte-derived CD11c+ , CD14+ and CD123+ dendritic cell infiltrates. Both COVID-associated and idiopathic perniosis showed striking expression of the type I interferon-inducible myxovirus resistance protein A (MXA), an established marker for type I interferon signalling in tissue. SARS-CoV-2 RNA, interleukin-6 and caspase 3 were minimally expressed and confined to mononuclear inflammatory cells. The biopsies from livedo/retiform purpura showed pauci-inflammatory vascular thrombosis without any MXA decoration. Blood vessels exhibited extensive complement deposition with endothelial cell localization of SARS-CoV-2 protein, interleukin-6 and caspase 3; SARS-CoV-2 RNA was not seen. CONCLUSIONS: COVID-19-associated perniosis represents a virally triggered exaggerated immune reaction with significant type I interferon signaling. This is important to SARS-CoV-2 eradication and has implications in regards to a more generalized highly inflammatory response. We hypothesize that in the thrombotic retiform purpura of critically ill patients with COVID-19, the vascular thrombosis in the skin and other organ systems is associated with a minimal interferon response. This allows excessive viral replication with release of viral proteins that localize to extrapulmonary endothelium and trigger extensive complement activation.

The role of sentinel lymph-node biopsy in the management of cutaneous melanoma.

The use of the sentinel lymph node biopsy (SLNB) procedure has developed from an experimental technique to one that is now widely accepted for carcinoma of the breast and for cutaneous melanoma. The status of the sentinel lymph node strongly correlates with survival in patients with melanoma, and it is used in many centers to determine which patients would benefit from elective lymph node dissection and possible chemotherapy. There is emerging yet still not decisive evidence that, when combined with completion lymphadenectomy, SLNB may prolong survival in patients with metastatic disease; however, controversy continues over the lower limit of defining how large a metastatic tumor deposit must be to be meaningful. In addition, many centers are considering SLNB to help stratify risk in melanocytic lesions of uncertain malignant potential.

Follicular cutaneous squamous cell carcinoma: an under-recognized neoplasm arising from hair appendage structures.

BACKGROUND: Cutaneous squamous cell carcinoma (SCC) with no demonstrable point of epidermal origin is problematic as it raises consideration of metastatic SCC histologically. There are rare case reports and series of SCC arising from the wall of hair follicle structures. Such lesions have been termed follicular SCC (FSCC). OBJECTIVES: To investigate the clinicopathological features of FSCC. METHODS: We prospectively collected cases of follicular SCC over a 5-year period. Follicular SCC is defined as a cutaneous SCC deriving from a pre-existing hair follicle structure. Lesions were considered to represent 'hybrid' SCCs if an interfollicular epidermal origin was also demonstrated; SCCs with > 50% of the origin from interfollicular epidermis were excluded. Histological features and clinical information were evaluated. RESULTS: We identified 61 cases of follicular SCC arising in 60 patients from a database of 5212 cutaneous SCCs encountered over the same time period by the same authors. There were 49 pure follicular SCCs and 12 hybrid lesions. The male to female ratio was 44 : 16; the mean age was 74 years (range 44-93). Follicular SCC represents 1·2% of all primary SCCs. Biopsies of such lesions, if the appendage structure of origin is not represented, are histologically indistinguishable from metastatic SCC. CONCLUSIONS: Recognition of this under-reported form of SCC is essential if an inappropriate diagnosis of metastatic SCC, with potentially harmful and inappropriate therapy and investigation, is to be avoided.

Atrophying tinea versicolor: a clinical and histological study of 12 patients.

BACKGROUND: We describe 12 patients with an atrophying dermatitis in whom the biopsy findings were compatible with tinea versicolor. DESIGN: We encountered 12 skin biopsies from 12 patients in whom a clinically atrophying dermatosis was associated with light microscopic (LM) evidence of atrophy and epidermal colonization by Pityrosporum sp. Formalin-fixed, paraffin-embedded tissue sections were cut at 5 microns and stained with H&E, alcian blue-PAS and PAS-diastase preparations. RESULTS: Five men and seven women aged 17-73 years in whom lesions characterized as atrophic plaques, patches or macules prompted clinical differential diagnoses including parapsoriasis or mycosis fungoides (MF), anetoderma, lupus erythematosus, and steroid atrophy. A LM examination showed epidermal colonization with pityrosporum hyphae and spores accompanied by variable epidermal and dermal atrophy characterized by rete-ridge effacement, subepidermal fibroplasia, pigment incontinence and elastolysis. CONCLUSIONS: Atrophying cutaneous lesions comprise part of the clinical spectrum of tinea versicolor for which we propose the term 'atrophying tinea versicolor'. The pathogenetic basis is unclear but could be the sequela of delayed type hypersensitivity and the release by T-helper lymphocytes of leukotrienes which perturb collagen metabolism and/or keratinocyte growth. Lesions may be mistaken clinically for MF or other atrophying dermatoses.

The spectrum of cutaneous lesions in rheumatoid arthritis: a clinical and pathological study of 43 patients.

INTRODUCTION: Rheumatoid arthritis (RA) is an idiopathic arthropathy syndrome that has a propensity to affect the small joints of the hands and feet with extra-articular manifestations comprising skin lesions, neuropathy, pericarditis, pleuritis, interstitial pulmonary fibrosis and a systemic polyarteritis nodosa (PAN)-like vasculitic syndrome. The most widely recognized skin lesion is the rheumatoid nodule. Other skin manifestations are poorly defined. MATERIALS AND METHODS: Using a natural language search of the authors' outpatient dermatopathology databases, skin biopsies from 43 patients with RA were selected for retrospective analysis in an attempt to define the dermatopathological spectrum of RA and its clinical correlates. RESULTS: The biopsies were categorized by the dominant histologic pattern, recognizing that in most cases there were additional minor reaction patterns. Palisading and/or diffuse interstitial granulomatous inflammation was the dominant pattern seen in 21 patients; the lesions included nodules, plaques and papules with a predilection to involve skin over joints. Besides interstitial histiocytic infiltrates and variable collagen necrobiosis, these cases also showed interstitial neutrophilia, vasculitis and pauci-inflammatory vascular thrombosis. The dominant morphology in 11 other patients was vasculopathic in nature: pauci-inflammatory vascular thrombosis, glomeruloid neovascularization, a neutrophilic vasculitis of pustular, folliculocentric, leukocytoclastic or benign cutaneous PAN types, granulomatous vasculitis, and lymphocytic vasculitis and finally occlusive intravascular histiocytic foci for which the designation of "RA-associated intravascular histiocytopathy" is proposed. Rheumatoid factor (RF) positivity and active arthritis were common in this group, with anti-Ro and anticardiolipin antibodies being co-factors contributing to vascular injury in some cases. Immunofluorescent testing in three patients revealed dominant vascular IgA deposition. In nine patients, the main pattern was one of neutrophilic dermal and/or subcuticular infiltrates manifested clinically as urticarial plaques, pyoderma gangrenosum and panniculitis. CONCLUSIONS: The cutaneous manifestations of RA are varied and encompass a number of entities, some of which define the dominant clinical features, such as the rheumatoid papule or subcutaneous cords, while others allude to the histopathology, i.e. rheumatoid neutrophilic dermatosis. We propose a more simplified classification scheme using the adjectival modifiers of "rheumatoid-associated" and then further categorizing the lesion according to the dominant reaction pattern. Three principal reaction patterns are recognized, namely extravascular palisading granulomatous inflammation, interstitial and/or subcuticular neutrophilia and active vasculopathy encompassing lymphocyte-dominant, neutrophil-rich and granulomatous vasculitis. In most cases, an overlap of the three reaction patterns is seen. Co-factors for the vascular injury that we believe are integral to the skin lesions of RA include RF, anti-endothelial antibodies of IgA class, anti-Ro and anticardiolipin antibodies.

Lupus profundus, indeterminate lymphocytic lobular panniculitis and subcutaneous T-cell lymphoma: a spectrum of subcuticular T-cell lymphoid dyscrasia.

INTRODUCTION: The diagnosis and classification of lymphocytic lobular panniculitis (LLP) has historically proven to be a difficult challenge. We encountered 32 cases of primary LLP which could be categorized as: 1) lupus erythematosus profundus (LEP) (19 patients); 2) an indeterminate group termed indeterminate lymphocytic lobular panniculitis (ILLP) (6 patients); and 3) subcutaneous T-cell lymphoma (SCTCL) (7 patients). OBJECTIVE: We attempted to better define the subtypes of LLP by morphologic, phenotypic and genotypic features and to correlate those features to clinical presentation and outcome. METHOD: Skin biopsy material was studied by conventional light microscopy, through immunophenotyping performed on sections from paraffin-embedded, formalin-fixed tissue and in some cases on sections of tissue frozen after receipt in physiological (Michel's) medium, and by polymerase chain reaction single-stranded conformational polymorphism analysis to assess for clonality of T-lymphocytes. Clinical features were correlated to histologic, phenotypic, and genotypic analyses. RESULTS: Patients with LEP had a prior diagnosis of LE or overlying skin changes which light microscopically were characteristic of LE. Patients with ILLP had no concurrent or prior history of LE, no systemic symptoms or cytopenias, and a clinical course not suggestive of lymphoma. Cases of SCTCL showed hemophagocytic syndrome and/or lesional progression with demise attributable to the disease. Lesions in all groups showed proximal extremity predilection. Females predominated in the LEP group. The average age of onset was 38, 40 and 55 years in the LEP, ILLP and SCTCL groups, respectively. Cytopenia was seen in 4 LEP patients; 1 also developed fever. In LEP and ILLP, lesions resolved with hydroxychloroquine and/or steroid therapy, with recurrences following cessation of therapy. In the SCTCL group 4 developed hemophagocytic syndrome, 4 died within 2 years of diagnosis, and 3 went into remission following chemotherapy. The LEP and SCTCL groups manifested histological similarities: dense perieccrine and lobular lymphocytic infiltration, lymphoid atypia, histiocytes with ingested debris, eosinophilic necrosis of the fat lobule and thrombosis. The atypical lymphocytes although pleomorphic did not have a cerebriform morphology. The infiltrate in ILLP had a similar cytomorphology and distribution with variable angioinvasion which in all save one case was of lesser intensity and was not associated with significant fat necrosis or vasculitis. Germinal centers, dermal/subcuticular mucin deposition and an atrophying interface dermatitis with hyperkeratosis and follicular plugging were largely confined to the LEP group. Erythrophagocytosis, characteristic of SCTCL, usually indicated a supervening subcuticular lymphoid dyscrasia when encountered in ILLP and LEP. SCTCL showed a selective loss of CD5 expression with or without diminution in CD7 and monoclonal CD3 expression. Of 4 cases studied, 3 showed a CD8 dominant infiltrate while 2 others exhibited CD56 and CD30 positivity, respectively. All cases of SCTCL with amplifiable DNA showed T-cell clonality. Similar molecular and phenotypic features indicative of subcuticular lymphoid dyscrasia were encountered in cases of LEP and ILLP including a reduction in CD5, CD7, and/or monoclonal CD3 expression, a preponderance of CD8 lymphocytes within the subcutaneous fat and T-cell clonality. These cases showed lymphoid atypia with variable erythrophagocytosis. Cases of phenotypically abnormal and/or clonal LEP showed one or more of local destruction, lesional size progression, fever, and cytopenias, but lesions responded to hydroxychloroquine and/or prednisone therapy and death attributable to panniculitis could not be documented. Cases that were phenotypically normal and without clonality had none of the aforesaid atypical clinical features. CONCLUSION: Lymphoid atypia, erythrophagocytosis, loss of certain pan T-cell markers, a reduced CD4/8 ratio and TCR rearrangement define subcuticular T-cell lymphoid dyscrasia, including a subset of LEP and ILLP. The subcuticular lymphoid infiltrates represent a spectrum of histologic, immunophenotypic, and molecular abnormalities which range from those which are clearly benign to those which are clearly neoplastic, and also encompasses those cases which defy precise classification into the two aforesaid poles.

The cutaneous neutrophilic vascular injury syndromes: a review.

The skin manifestations of vasculitis reflect injury by all of the classic immune reactions of Gell and Coombs. As the skin affords a window of opportunity for the clinician to obtain tissue for diagnostic purposes in patients with systemic vasculitic syndromes, a thorough understanding of the dermatopathologic manifestations of those systemic diseases is a considerable asset to the practicing pathologist. This review focuses on those systemic diseases that can provoke a small vessel neutrophilic injury pattern in the skin and provides clues by which these diseases can be separated from each other and from their innocuous mimics in which cutaneous vascular injury is the only significant consequence.

The cutaneous pathology of lupus erythematosus: a review.

The presentation of lupus erythematosus (LE) ranges from a skin rash unaccompanied by extracutaneous stigmata to a rapidly progressive lethal multiorgan disease. The diagnosis and subclassification is traditionally based on the correlation of serological and clinical findings. The latter include a photoinduced skin rash, arthralgia, arthritis, fever, Raynaud's phenomenon, anemia, leukopenia, serositis, nephritis and central nervous sysdtem disease. The conventional classification scheme includes systemic, subacute cutaneous and discoid LE. Recent advances in our understanding of the cutaneous histopathology which correlates with the traditional forms of LE, along with certain novel LE subtypes, are the focus of this review. In addition to the main subtypes of LE, we will discuss associated vasculopathic lesions and the contribution of immunofluorescence microscopy to the diagnosis of LE and related connective tissue disease syndromes. Consideration will be given to unusual variants of LE such as anti-Ro/SSA-positive systemic lupus erythematosus (SLE), bullous SLE, lymphomatoid LE, lupus erythematosus profundus, drug induced LE, linear cutaneous LE, chiblains LE and parvovirus B19-associated LE.

Towards non-invasive screening of skin lesions by near-infrared spectroscopy.

A noninvasive tool for skin tumor diagnosis would be a useful clinical adjunct. The purpose of this study was to determine whether near-infrared spectroscopy can be used to noninvasively characterize skin lesions. In vivo visible- and near-infrared spectra (400--2500 nm) of skin neoplasms (actinic keratoses, basal cell carcinomas, banal common acquired melanocytic nevi, dysplastic melanocytic nevi, actinic lentigines, and seborrheic keratoses) were collected by placing a fiberoptic probe on the skin. Paired t tests, repeated measures analysis of variance and linear discriminant analysis were used to determine whether significant spectral differences existed and whether spectra could be classified according to lesion type. Paired t tests showed significant differences (p < 0.05) between normal skin and skin lesions in several areas of the near-infrared spectrum. In addition, significant differences were found between the lesion groups by analysis of variance. Linear discriminant analysis classified spectra from benign lesions compared with premalignant or malignant lesions with high accuracy. Near-infrared spectroscopy is a promising noninvasive technique for the screening of skin lesions.

A causal role for parvovirus B19 infection in adult dermatomyositis and other autoimmune syndromes.

BACKGROUND: Infection with parvovirus B19 (B19) has been associated with connective tissue disease (CTD) stigmata, namely, a systemic lupus erythematosus (SLE)-like illness, seronegative polyarthritis resembling rheumatoid arthritis, and vasculitis. The dermatopathology and pathogenetic basis of such B19-associated CTD-like syndromes have not been elucidated. OBJECTIVE: We attempted to document persistence of the B19 genome in skin lesions of 7 patients with CTD-like symptomatology following B19 infection and to correlate systemic manifestations to dermatopathological findings. METHOD: In 7 prospectively encountered patients in whom history, clinical signs and/or serology supported a diagnosis of CTD in the setting of B19 infection, dermatopathological and clinical features were correlated. Parvovirus B19 viral genome was sought in skin tissue using the polymerase chain reaction (PCR). RESULTS: Two patients had clinical features diagnostic of myopathic dermatomyositis (DM), 1 of whom is still symptomatic 1.5 years after the onset of her illness, and the other has had typical clinical features of DM for a duration of 3.5 years. A 3rd patient with SLE remains symptomatic 4 years after the onset of her illness. A 4th patient has persistent seronegative symmetrical polyarthritis of 6 years' duration and cutaneous lesions of granuloma annulare (GA). The 5th patient has a 1.5-year history of debilitating polyarthritis and cutaneous lesions with overlap features of DM and subacute cutaneous LE (SCLE). The 6th patient has had a persistent folliculocentric necrotizing vasculitis for 3 years. The 7th patient has a 1-year history of microscopic polyarteritis nodosa (PAN) with cutaneous vasculitis and persistent active renal disease. In 4 patients, exposure to children with fifth disease immediately preceded the onset of their CTD. Parvovirus B19 infection was documented serologically in 6 patients with antibodies of IgG subclass in 6 and of IgM subclass in 1. Four of 6 patients questioned had a history of atopy. Skin biopsies from patients with clinical features of SLE or DM demonstrated an interface dermatitis with dermal mucinosis. A necrotizing vasculitis with epithelial pustulation was seen in 2 patients. Interstitial GA-like infiltrates were seen in 5 cases. Immunofluorescent (IF) testing revealed a positive lupus band test (LBT) and epidermal nuclear and vascular staining for IgG and C5b-9 in the SLE patient. One DM patient had a negative LBT in concert with C5b-9 deposition along the dermoepidermal junction (DEJ) and within blood vessels while the other showed endomysial vascular Cs5b-9 deposition. In all patients, skin biopsy material contained B19 genome, which was absent in the serum of 4 patients analyzed. Symptomatic relief followed immunosuppressive and immunomodulatory therapy with agents including prednisone, cyclophosphamide, hydroxychloroquine, non-steroidal anti-inflammatory drugs and etanercept, but no patient has had complete symptom resolution. CONCLUSIONS: Persistent B19 infection may be of pathogenetic importance in certain prototypic CTD syndromes, to which underlying immune dysregulation associated with a blunted IgM response to viral antigen may predispose. Anti-viral therapy might be worthy of consideration since traditional immunosuppressive therapy was unsuccessful in our cases.

Necrotizing eosinophilic folliculitis as a manifestation of the atopic diathesis.

BACKGROUND: Eosinophilic folliculitis (EF) is an idiopathic eruption of sterile pustules and papules involving the trunk, face, and extremities, associated in many cases with human immunodeficiency virus (HIV) infection. The classic histopathology is one of follicular-based, eosinophilic spongiosis with variable microabscess formation. We describe nine HIV-negative patients who manifested a novel form of pustular EF in the setting of atopy. MATERIALS AND METHODS: Paraffin sections of skin biopsies from ten patients, stained with hematoxylin and eosin and special preparations to evaluate for microbial pathogens, were examined. Detailed clinical histories and serologic studies were obtained. RESULTS: Among the clinical presentations in seven men, two women, and one girl (age range, 11-62 years) were ulcerative and/or nodular plaques mainly on the face and/or extremities, sometimes in an annular configuration. The clinical considerations included deep mycotic infection, ulcerative herpes, systemic vasculitis, Mucha Haberman disease, and pyoderma gangrenosum. All patients had a personal and/or family history of atopy. Co-existent medical illnesses included psoriasis, lupus erythematosus, and lymphoproliferative disease. One patient was on a calcium channel blocker, one on multiple antidepressants, and two on antihistamines, all of which are associated with immune dysregulation. All skin biopsies showed variable intra- follicular eosinophilic microabscesses, follicular necrosis, folliculocentric necrotizing eosinophilic vasculitis, marked degeneration of connective tissue fiber elements, and striking tissue eosinophilia, including flame figure formation and dermal eosinophilic abscesses. Apart from commensals, such as Pityrosporum and Demodex, microbial pathogens were not identified. CONCLUSIONS: The presentations differed from conventional EF by virtue of a strong association with atopy and by the presence of ulceration, nodule formation, follicular and dermal necrosis, and eosinophilic vasculitis. We propose the term "necrotizing eosinophilic folliculitis," and suggest that the basis of this novel form of EF is an unrepressed T-helper lymphocyte type 2 (Th2)-dominant response to various epicutaneous stimuli in patients with atopy, the prototypic immune dysregulatory state associated with a Th2-dominant cytokine milieu.

The cutaneous manifestations of human parvovirus B19 infection.

The prototypical cutaneous manifestations of human parvovirus B19 (B19) infection include a petechial eruption in a glove and stocking distribution, reticular truncal erythema, and the "slapped cheek" sign. An association with connective tissue disease (CTD) stigmata has recently been made. The clinical and dermatopathologic findings in 14 patients whose skin lesions were accompanied by serological evidence of B19 infection or documentation of B19 genome in lesional skin are presented. The authors encountered skin biopsy specimens from 14 patients who presented with skin eruptions accompanied by clinical signs or serology suggestive of antecedent B19 infection. Clinical findings were correlated to the light microscopic appearance of the lesions and the presence of B19 genome in lesional skin. The study group comprised 9 women, 3 men, and 2 boys. Eruptions characteristic of fifth disease, including the slapped cheek sign, reticulated truncal erythema, and acral petechiae, were present in 3 patients, 1 of whom later developed granuloma annulare. The other patients had atypical clinical presentations comprising an asymptomatic papular eruption (2), an eruption clinically resembling Sweet's syndrome (3), myopathic dermatomyositis (DM) (2), lupus erythematosus (LE)-like syndromes (2), and lower-extremity palpable purpura (2). Skin biopsy specimens in 12 cases showed interstitial histiocytic infiltrates with piecemeal fragmentation of collagen and a mononuclear cell-predominant vascular injury pattern. Other features included an interface dermatitis, eczematous alterations, and papillary dermal edema. Lesions with features of DM or LE also showed mesenchymal mucinosis, whereas a biopsied lesion of palpable purpura showed leukocytoclastic vasculitis (LCV). Immunofluorescent testing showed a positive lupus band test (LBT) with epidermal IgG and C5b-9 decoration in 1 patient with a systemic LE-like illness, whereas the DM patients had negative LBTs and vascular C5b-9 deposition typical for DM. Skin biopsy specimens from 11 patients, including those whose presentations resembled LE and DM, were positive for B19 genome. The dermatopathology of B19 infection suggests tissue injury mediated by delayed-type hypersensitivity, by antibody-dependent cellular immunity directed at microbial antigenic targets in the epidermis and endothelium, and by circulating immune complexes in the setting of LCV. These mechanisms appear to generate a clinical and histopathological picture that recapitulates that of CTD.

Lichenoid and granulomatous dermatitis.

BACKGROUND: The prototypic lichenoid eruptions, lichen planus (LP), lichenoid drug eruptions, secondary syphilis, and collagen vascular disease, are defined histologically by a band-like lymphocytic infiltrate in close apposition to the epidermis. We describe a novel form of lichenoid dermatitis with a granulomatous component. DESIGN: Skin biopsies from 40 patients demonstrating a band-like lymphocytic infiltrate with concomitant granulomatous inflammation were encountered over 4 years. Clinicians were contacted to elucidate underlying triggers and medical illnesses. RESULTS: A lichenoid dermatitis, a linear eruption, vasculitis, annular erythema, and erythroderma were among the clinical presentations. A drug-based etiology was implicated in 14 cases: the drugs included antibiotics, lipid-lowering agents, anti-inflammatory drugs, antihistamines, hydroxychloroquine sulfate, and angiotensin-converting enzyme inhibitors. Over one-third of patients with drug-related eruptions had other medical illnesses associated with cutaneous granulomatous inflammation, namely rheumatoid arthritis (RA), Crohn's disease, hepatitis C, diabetes mellitus, and thyroiditis. A microbial trigger was implicated in 12 patients in the context of infective id reactions to herpes zoster, Epstein-Barr virus (EBV), or streptococci, or active infections by Mycobacterium tuberculosis, M. leprae, fungi, and spirochetes. The remainder had hepatobiliary disease and RA without obvious exogenous triggers, cutaneous T-cell lymphoma (CTCL), and idiopathic lichenoid eruptions (i.e. LP, lichen nitidus, and lichen striatus). One patient with LP had underlying multicentric reticulohistiocytosis. The histiocytic infiltrate assumed one or more of five light microscopic patterns: (i) superficially disposed loose histiocytic aggregates; (ii) cohesive granulomata within zones of band-like lymphocytic infiltration with or without deeper dermal extension; (iii) a diffuse interstitial pattern; (iv) scattered singly disposed giant cells; and (v) granulomatous vasculitis. Additional features included lymphocytic eccrine hidradenitis in those patients with drug reactions, hepatobiliary disease, and antecedent viral illnesses, tissue eosinophilia and erythrocyte extravasation in drug hypersensitivity, granulomatous vasculitis in patients with microbial triggers, drug hypersensitivity or RA, and lymphoid atypia in lesions of CTCL or drug hypersensitivity. CONCLUSIONS: The cutaneous lichenoid and granulomatous reaction may reflect hepatobiliary disease, endocrinopathy, RA, Crohn's disease, infection, or a drug reaction. One-fifth of cases represent idiopathic lichenoid disorders. Lymphoproliferative disease or pseudolymphomatous drug reactions must be considered in those cases showing lymphoid atypia.

Atypical pigmentary purpura: a clinical, histopathologic, and genotypic study.

BACKGROUND: The pigmentary purpuras (PPs) are a heterogeneous group of dermatoses defined by specific clinicopathologic features but sharing, at the light microscopic level, superficially disposed dermal lymphocytic infiltrates and hemorrhage. The term atypical pigmentary purpura (APP) is used by the authors in reference to cases of PP in which individual lesions, although clinically presenting as PP, show morphological features typically associated with mycosis fungoides (MF) including Sezary cells and epidermotropism. The integrated concept of lymphocyte atypia and PP is a confusing and enigmatic one to which reference in the literature has been previously made. Specifically, there are reports of PP presaging fully evolved MF, lymphoid atypia has been identified in lesions of routine PP and MF with purpuric features has been described. The clinical, light microscopic, and genomic features of biopsied lesions showing pathological features of APP and which clinically were consistent with PP is explored. DESIGN: The light microscopy of skin biopsy specimens from 34 patients with a pathological diagnosis of APP was correlated to medical and drug histories. In 14 cases, adequate tissue was present in the paraffin blocks to allow DNA extraction. The polymerase chain reaction (PCR) was used in these 14 cases to explore for rearrangement of the T-cell receptor. Fisher's exact test and pair wise exact tests were used to assess the significance of histological differences between cases determined by dinical features to be of MF- or drug-related origin, or to be idiopathic in nature. RESULTS: Of 34 patients, 7 were held to have MF related PP; specifically these patients had violaceous, infiltrative, variably purpuric plaques on trunk, buttocks, and thighs accompanied by typical PP lesions which occurred either concomitant to or preceded the MF lesions. In 10 cases, a diagnosis of idiopathic PP was made whereby the clinical presentation was characteristic of PP; there were no concomitant lesions suspicious for MF and a drug-based origin was excluded. A drug-based origin was established in 17 patients based on lesional onset related to initiation (5 patients) and/or resolution after discontinuation (12 patients) of drugs including calcium channel blockers, lipid-lowering agents, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, antihistamines, antidepressants, or analgesics. There was considerable overlap histologically between all 3 groups including the degree of lymphoid atypia in the dermis, the presence of dermal-based Sezary cells, the degree and pattern of epidermotropism, the paucity of other inflammatory cell elements, and the presence of laminated dermal sclerosis. Morphological features predictive of MF related APP over the other 2 groups were intraepidermal lymphocytes which were more atypical than the dermal-based infiltrate. Intraepidermal Sezary cells were less frequent in biopsies of drug-related APP relative to idiopathic PP (IPP) and MF related PP. PCR studies conducted in 14 cases (2 cases of MF, 6 cases of drug-related APP, and 6 cases of IPP) revealed clonality in 2 cases of drug-related APP and 2 cases of IPP; the 2 studied MF-related cases did nor show clonal restriction. CONCLUSION: APP should not be equated with purpuric MF; it is not necessarily a precursor lesion of MF, and may be of drug-based origin. Clinical features are critical to the final assessment because there is overlap pathologically in the 3 clinical subtypes of APP.

Recent advances in the pathology of cutaneous drug eruptions.

Cutaneous reactions to drug therapy may be of either immunologic or nonimmunologic etiology. It is important that the dermatologist and pathologist be familiar with these types of cutaneous reactions. This article discusses the clinical features, pathogenesis, and histopathology of various cutaneous drug eruptions.

A clinical and histologic study of 37 cases of immunoglobulin A-associated vasculitis.

Immunoglobulin (Ig) A-associated vasculitis is commonly equated with the multiorgan systemic vasculitic syndrome Henoch-Schonlein purpura (HSP), which occurs predominantly in the pediatric age group. By natural language search of the databases of two outpatient dermatopathology practices, the authors selected for review 37 cases of IgA-associated vasculitis, 23 of which were associated with antecedent infection, most commonly of the upper respiratory tract. Criteria for a diagnosis of HSP were met in 15 cases, 13 of which were in the setting of prior infection. Lower extremity skin involvement was ubiquitous. A more widespread form of vasculitis was also seen, particularly in the setting of previous infection. Several of the patients with previous infection had underlying medical illnesses including rheumatoid arthritis, atopy, renal failure, lupus erythematosus, insulin dependent diabetes mellitus, autoimmune thyroid disease, and Wegener's granulomatosis. In those patients lacking an apparent microbial trigger, Sjogren's disease with anti-Ro antibodies and hypergammaglobulinemia, lupus erythematosus, inflammatory bowel disease, IgA paraproteinemia, bronchogenic and prostatic carcinoma, cryoglobulinemia, and lymphoma were uncovered. Regardless of whether an infectious stimulus was implicated, certain cofactors with the potential to enhance vascular injury were uncovered; these included anti-Ro antibodies, antineutrophil cytoplasmic antibody, diabetic microangiopathy, and a hyperviscosity state. In the infective group, a pustular vasculitis, defined as a neutrophilic vascular reaction in concert with epithelial pustulation, was seen in 81% of cases versus 33% in the noninfectious group (p = 0.02). The prototypic histomorphology in the noninfective group was one of a mild cell poor leukocytoclastic vasculitis; Vasculitis was of greater severity in patients with antecedent infection (p = 0.026). An infectious trigger, typically of mucosal origin, can frequently be identified in patients with cutaneous IgA-associated vasculitis, especially those with the symptom complex of HSP. The light microscopy appears to distinguish patients who have an infectious trigger from those who do not. IgA-associated vasculitis may be a clue to the presence of certain underlying disorders where there is immune dysregulation or enhanced susceptibility to immune complex entrapment.

Infrared spectra of basal cell carcinomas are distinct from non-tumor-bearing skin components.

Infrared spectroscopy, by probing the molecular vibration of chemical bonds, directly indicates tissue biochemistry. An expanding body of literature suggests that infrared spectra distinguish diseased from normal tissue. The authors used infrared spectroscopy to examine basal cell carcinoma to explore distinctive characteristics of basal cell carcinoma versus normal skin samples and other skin neoplasms. Spectra of epidermis, tumor, follicle sheath, and dermis were acquired from unstained frozen sections, and analyzed qualitatively, by t-tests and by linear discriminant analyses. Dermal spectra were significantly different from the other skin components mainly due to absorptions from collagen in dermis. Spectra of normal epidermis and basal cell carcinoma were significantly different by virtue of subtle differences in protein structure and nucleic acid content. Linear discriminant analysis characterized spectra as arising from basal cell carcinoma, epidermis, or follicle sheath with 98.7% accuracy. Use of linear discriminant analysis accurately classified spectra as arising from epidermis overlying basal cell carcinoma versus epidermis overlying nontumor-bearing skin in 98.0% of cases. Spectra of basal cell carcinoma, squamous cell carcinoma, nevi, and malignant melanoma were qualitatively similar. Distinction of basal cell carcinoma, squamous cell carcinoma, and melanocytic lesions by linear discriminant analyses, however, was 93.5% accurate. Therefore, spectral separation of abnormal versus normal tissue was achieved with high sensitivity and specificity, which points to infrared spectroscopy as a potentially useful screening tool for cutaneous neoplasia.

Malignant melanoma with prominent pigment synthesis: "animal type" melanoma--a clinical and histological study of six cases with a consideration of other melanocytic neoplasms with prominent pigment synthesis.

Rare skin neoplasms in humans, comprising nodules of heavily melanized cells, mimic melanocytic neoplasms seen in horses and laboratory animals and thus are termed animal type melanomas. In part because of their rarity, behavior is unpredictable; many cases manifest a long indolent phase, and metastases are reportable. Over 6 years, the authors encountered nine skin and one lymph node biopsy specimens from six patients in whom light microscopy of formalin-fixed, paraffin-embedded tissue sections stained with hematoxylin and eosin showed melanocytic neoplasms with prominent pigment synthesis. Clinical follow-up was obtained by telephone contact with clinicians. There were three women, two men, and one boy, aged 9 to 85 years, whose lesions were described as blue-black nodules with irregular borders from 1.0 to 4.0 cm in size, located on the scalp, lower extremities, back, and sacrum. The dermatopathology comprised confluent dermal sheets of heavily melanized cells whose nuclei, where discernible, were large with irregularly thickened membranes, coarse chromatin, prominent, often spiculated nucleoli, and irregular parachromatinic clearing. Mitoses were infrequent. Four lesions had an epidermal component. One patient suffered metastases to regional lymph nodes, liver, and lungs with lethal effect, one experienced regional lymph node metastases but is still alive, one had local cutaneous metastases but was lost to follow-up, and one has a chest wall mass that has not yet been investigated. This rare dermal-based melanocytic neoplasm with prominent pigment synthesis, the animal type melanoma, has a biological behavior difficult to predict on morphological grounds. We advise complete excision with a 1.0- to 2.0-cm margin of normal skin and clinical investigation for regional or distant metastases.