[Cutaneous sarcomas: update on selected fibrohistiocytic and myofibroblastic tumors]. / Kutane Sarkome: update ausgewählter Entitäten fibrohistiozytärer und myofibrozytärer Morphologie.

BACKGROUND: Malignant fibrohistiocytic tumors are a heterogeneous group of mesenchymal neoplasms that may occur in the skin and subcutaneous tissues. DIAGNOSIS: Diagnosis of these tumors may be difficult, as they are rare, and a wide morphological diversity of types and subtypes has been described. In this update, relevant aspects of selected entities like dermatofibrosarcoma protuberans, desmoid tumor, atypical fibroxanthoma, pleomorphic dermal sarcoma, and myxofibrosarcoma are discussed according to the WHO classification of 2013. The typical clinical feature of these tumors is their mostly asymptomatic appearance. For diagnosis, the histologic workup is therefore the key feature; herein immunohistochemistry as well as molecular diagnostics become increasingly important. THERAPY: The primary treatment for locally resectable tumors is complete surgical removal; chemotherapy, radiation, and targeted therapies with kinase inhibitors are available for inoperable and metastatic disease.

Nonablative laser treatment of wrinkles: meeting the objective? Assessment by 25 dermatologists.

BACKGROUND: Established skin resurfacing methods causing superficial wounds and extended recovery times have become less popular since the introduction of nonablative lasers. OBJECTIVES: To evaluate the clinical efficacy of a nonablative 1450-nm diode laser system. METHODS: Nine patients (Fitzpatrick skin type II-IV) with periorbital wrinkling class I-II were treated three times at 3-weekly intervals with a 1450-nm diode laser. Clinical outcome was determined by 25 independent dermatologists evaluating standardized photographs taken before treatment and 1 month after treatment. RESULTS: The patients were satisfied with the procedure, and reported a mild to moderate improvement in all cases. Among 25 dermatologists, only two provided ratings which were significantly in favour of a positive treatment effect. CONCLUSIONS: Nonablative laser treatment subjectively satisfies patients but does not convince objective judgement.

Melanoma with benign melanocytic naevus components: reappraisal of clinicopathological features and prognosis.

The clinicopathological features and prognosis of primary cutaneous malignant melanoma with benign melanocytic naevus (BMN) components are still under debate. The purpose of this study was to characterize further the clinical and histopathological features of naevus-associated melanomas, with emphasis on the BMN components, and to examine their prognosis based on a large series. Following a histopathological review of 667 consecutive cases of primary cutaneous melanoma, 148 melanomas with BMN components (22.1%) were identified for further study. A control group of 519 melanomas without BMN components seen in a similar period were also studied. Clinically, patients with melanomas containing BMN components (n = 148; age range 25-86 years, mean age 54 +/- 16 years; male to female ratio 1:1.02) presented with tumours located mainly on the trunk (34.5%), followed by the upper extremities (24.3%), lower extremities (20.3%), and head and neck (14.2%). Compared with tumours without BMN components (n = 519; age range 19-89 years, mean age 57 +/- 15 years; male to female ratio 1:1.3), melanomas with BMN components occurred in slightly younger individuals (P = 0.027). Histopathologically, BMN components mainly showed features of acquired naevi (total 87 cases; dysplastic, 80 cases; banal, seven cases) or congenital naevi (total 57 cases; superficial, 56 cases; deep, one case), but a minority of these lesions (four cases) could not be further subcategorized. Generally, melanomas containing BMN components were relatively thinner than melanomas without BMN components (mean Breslow index 0.95 +/- 0.83 mm and 1.3 +/- 1.6 mm, respectively) (P = 0.015). The follow-up data available in 69 patients with naevus-associated melanomas consistently revealed a relatively good outcome (5 year metastasis-free survival rate 93.75%), although no statistical difference in prognosis was observed between this group and a subset of 283 melanomas patients without BMN components stratified by tumour thickness. We conclude that BMN components in naevus-associated melanomas constitute a heterogeneous group morphologically, consisting mainly of dysplastic and superficial congenital naevi. This finding indicates a more important role for superficial congenital naevus as a precursor lesion of naevus-associated melanomas than presently recognized. Patients with naevus-associated melanomas generally show a good clinical outcome, reflecting their small Breslow index.

Resolution of granulomatous rosacea after eradication of Helicobacter pylori with clarithromycin, metronidazole and pantoprazole.

The aetiopathogenetic role of Helicobacter pylori in rosacea remains controversial. We report a 27-year-old man with a 4-year history of intractable rosacea. Histopathology showed epithelioid granulomas. H. pylori infection was proven directly on gastroscopy and by serological testing. Treatment with clarithromycin, metronidazole and pantoprazole eradicated H. pylori. Skin changes were markedly improved by the end of this therapy and had resolved completely 2 months later. The patient has been followed up, and has remained free of symptoms for 3 years. We suggest that H. pylori may be involved in the aetiopathogenesis of granulomatous rosacea.

Collision of squamous-cell carcinoma with melanoma in situ in a child with xeroderma pigmentosum.

Coexistence (collision) of two different neoplasms in the same lesion has previously been documented by several authors. In this report, we describe a 13-year-old boy with xeroderma pigmentosum presenting with squamous-cell carcinoma and melanoma arising at the same site on the nose. Histopathologically, the melanoma component of the lesion was located mainly eccentrically to the squamous-cell carcinoma component. Immunohistochemical stains confirmed the histopathologic findings. Mutations for p53 assessed using single-strand conformation polymorphism, and sequencing analysis revealed a CC-to-TT transition at codon 159 of the p53 gene in the squamous-cell component but not in the melanoma component. This finding suggests a possible role for UV in the pathogenesis of at least the squamous-cell component of the tumor. To the best of our knowledge, this is the first report of a collision tumor comprising squamous-cell carcinoma and melanoma arising in childhood.

Accidental bullous phototoxic reactions to bergamot aromatherapy oil.

Oil of bergamot is an extract from the rind of bergamot orange (Citrus aurantium ssp bergamia) that has a pleasant, refreshing scent; until a few years ago it had been widely used as an ingredient in cosmetics but was restricted or banned in most countries because of certain adverse effects. More recently, oil of bergamot preparations have been gaining renewed popularity in aromatherapy. Oil of bergamot possesses photosensitive and melanogenic properties because of the presence of furocoumarins, primarily bergapten (5-methoxypsoralen [5-MOP]). However, 5-MOP is also potentially phototoxic and photomutagenic. Despite its increasing application, there are only a few recent reports of phototoxic reactions to bergamot aromatherapy oil. We describe two patients with localized and disseminated bullous phototoxic skin reactions developing within 48 to 72 hours after exposure to bergamot aromatherapy oil and subsequent ultraviolet exposure. One patient (case 2) had no history of direct contact with aromatherapy oil but developed bullous skin lesions after exposure to aerosolized (evaporated) aromatherapy oil in a sauna and subsequent UVA radiation in a tanning salon. This report highlights the potential health hazard related to the increasing use of psoralen-containing aromatherapy oils.

Grover's disease associated with Sarcoptes scabiei.

An 83-year-old man presented with a 4-month history of discrete, itchy papules mainly distributed on the trunk and upper extremities. Histopathologic examination of two biopsies from lesions on the trunk revealed mainly focal suprabasal acantholysis and an inflammatory infiltrate composed mainly of lymphocytes with a few eosinophils. The overall clinical and histopathologic features were consistent with Grover's disease. However, scrapings taken from the skin lesions showed numerous mites of Sarcoptes scabiei. Subsequent treatment with an antiscabies cream led to a rapid complete cure, and no skin lesions have been observed during a 6-month follow-up. A review of the literature revealed 2 other cases of cutaneous lesions fulfilling the clinical and histopathologic features of Grover's disease in which mites of S. scabiei were demonstrated. Our observation further highlights the unusual association of Grover's disease with S. scabiei mites and emphasises the importance of excluding this easily treatable skin infestation in all patients with Grover's disease.

Cutaneous myoepithelioma: an under-recognized cutaneous neoplasm composed of myoepithelial cells.

Benign and malignant neoplasms of myoepithelial cells comprise a rare but well-characterized group of tumors, among which myoepithelioma of the salivary glands is the best known. Extrasalivary examples of myoepithelioma also have been described in the breast, larynx, and retroperitoneum. Recently, myoepithelioma of the soft tissue also has been reported. According to this description, myoepithelioma and mixed tumors arising in the skin and subcutis represent points along a clinicopathologic spectrum of cutaneous and soft-tissue tumors. To the best of our knowledge, there has been only one case report of an entirely cutaneous myoepithelioma in the literature. We report herein five additional examples of purely myoepithelial tumors located exclusively in the dermis. Histopathologically, the neoplasms were well-circumscribed dermal lesions composed of fascicles of spindle cells with eosinophilic cytoplasm and ovoid-to spindle-shaped nuclei. Focally, neoplastic aggregations of more epithelioid cells representing large round cells with abundant pale cytoplasm arranged in solid clusters, cords, or strands were also seen. Ductal differentiation was not identified in either of these solid aggregations of epithelioid cells or in the fascicles of spindle-shaped cells. Nuclear pleomorphism in epithelioid and spindle-cell areas was mild, and mitotic figures were very sparse. In some cases, small, necrotic areas were seen within the solid aggregations of spindle-shaped cells. Neoplastic stroma was scant and composed of fibrillary collagen and abundant mucin. In one case, the stroma consisted of clusters of mature adipocytes intermingled with fascicles of myoepithelial cells. Areas of chondroid or osteoid metaplasia were not seen in any of the cases. Immunohistochemically, neoplastic cells expressed positivity for muscle specific actin (HHF35), alpha smooth muscle actin (IA4), S-100 protein, glial fibrillary acidic protein (GFAP), and epithelial membrane antigen (EMA), whereas stains for pan-cytokeratin (MNF116) were focal and weak. The findings in this report expand the clinical and histopathologic spectrum of cutaneous myoepithelioma, an under-recognized cutaneous neoplasm of myoepithelial cells.

Granulomatous cheilitis and Borrelia burgdorferi: polymerase chain reaction and serologic studies in a retrospective case series of 12 patients.

BACKGROUND: Granulomatous cheilitis (GC) is a chronic granulomatous inflammation of the lips of unknown etiology, which may be associated with peripheral facial nerve paralysis and/or lingua plicata (Melkersson-Rosenthal syndrome [MRS]). Borrelia burgdorferi is a spirochete that causes Lyme borreliosis, a multisystemic infectious disease with frequent occurrence of facial nerve paralysis. An etiologic role of B burgdorferi in various granulomatous diseases has been suggested. The present study was performed to examine a possible causative role of B burgdorferi for GC/MRS by B burgdorferi-specific polymerase chain reaction analysis of biopsy specimens from affected lip tissue and determination of B burgdorferi IgG and IgM serum antibodies using enzyme-linked immunosorbent assay and immunoblot tests. OBSERVATIONS: We examined a retrospective case series of 12 patients with GC/MRS from a Lyme borreliosis endemic area (median duration of disease, 8 months [range, 3-348 months]). Borrelia burgdorferi-specific DNA could not be amplified by polymerase chain reaction in any of the 12 patients. One (13%) of 8 patients tested had a serum B burgdorferi IgG response on enzyme-linked immunosorbent assay, and 2 patients (25%) had an IgM response, but immunoblot testing yielded negative results in all 8 patients. CONCLUSION: The results of the present study do not indicate that B burgdorferi has an etiologic role in GC/MRS.

Basaloid neoplasms in nevus sebaceus.

BACKGROUND: Nevus sebaceus (NS) (organoider nevus) may frequently be associated with the development of a number of benign and malignant neoplasms among which basaloid neoplasms are the most common. Histopathologic criteria for diagnosis and classification of basaloid proliferations arising in NS are still debated. Most previous investigators have considered them to represent mainly basal cell carcinomas (BCCs). On the contrary, a number of recent authors have proposed that most basaloid neoplasms in NS exhibit predominantly morphologic features implying benignancy, thus representing trichoblastomas (TBs). In this study, we attempted to characterize better the histopathologic features of basaloid neoplasms in NS in a large series based on current morphologic criteria. METHODS: Three-hundred and sixteen cases of NS seen over 19 years were consecutively sampled and reviewed for basaloid neoplasms. Twenty-four cases of basaloid neoplasms in NS were identified and categorized based on current histopathologic criteria either as TB or BCC. For comparison of histopathologic features, 37 solitary TB were also studied. RESULTS: Following histopathologic analysis, 22 cases were categorized as TB (91.6%, 10 males, 12 females; mean age 40.8 years, range 19-78 years) and 2 cases as BCC (8.4%, 1 male, 1 female; 32 years and 40 years). Clinical features in both groups were generally similar. The lesions presented exclusively on the head and neck as skin colored to pigmented papules or nodules within NS (scalp in 19 TB cases and 1 BCC case; face in 2 TB cases and 1 BCC case; neck in 1 TB case). Histopathologically, TB in NS were characterized by smooth-bordered basaloid aggregations with either a nodular and/or a superficial pattern, abundant fibrous stroma with focal clefts within the stroma, and prominent features of limited follicular differentiation (rudimentary follicular germs in concert with papillae). In contrast, BCC in NS showed basaloid aggregations that vary markedly in size and shape, scant fibrous stroma, focal mucinous clefts between basaloid aggregations and surrounding stroma, and lack of prominent rudimentary follicular germs in concert with papillae. Remarkably, sections in a few cases of TB showed features occasionally found in BCCs but presently widely considered to be unspecific (e.g., ulceration, cystic degeneration, and focal clefts between basaloid aggregations and surrounding stroma). Two cases of TB in NS were associated with a sebaceoma and 1 case with a desmoplastic trichilemmoma. Follow-up data in 14 TB cases and 2 BCC cases (mean follow-up 28.8 months; range 1 to 160 months) revealed no local recurrences or distant metastases. CONCLUSION: Our study confirms that the vast majority of the basaloid neoplasms arising in NS show clear-cut morphologic criteria for TB, whereas only a few cases display histopathologic features consistent with BCC. In a minority of cases, basaloid neoplasms with overall morphologic features of TB may present problems in diagnosis when they exhibit a few histopathologic features traditionally associated with BCC or when they occur in combination with other adnexal neoplasms.

Auriculotemporal (Frey) syndrome in late childhood: an unusual variant presenting as gustatory flushing mimicking food allergy.

Auriculotemporal or Frey syndrome is characterized mainly by recurrent episodes of facial gustatory flushing and/or sweating, limited to the cutaneous distribution of the auriculotemporal nerve. Although relatively common in adults following injury to the auriculotemporal nerve or parotid disease, the condition has rarely been reported in children. Moreover, in childhood, auriculotemporal syndrome has been described mainly in infancy and early childhood as a sequel of perinatal birth trauma resulting from assisted forceps delivery. We report a 13-year-old girl with a 2-month history of recurrent, painless, preauricular gustatory flushing without sweating, initially suspected to be a food allergy. Detailed inquiry revealed a history of a bicycle accident with mandibular condyle fracture 7 years prior to the onset of symptoms. Our patient demonstrates an unusual presentation of auriculotemporal syndrome in late childhood as gustatory flushing mimicking food allergy. Awareness of this variant is essential for prompt recognition, thus avoiding unnecessary laboratory tests, especially as this condition usually resolves spontaneously.

Subcutaneous trichoblastoma.

We have recently observed three examples of solitary trichoblastomas (TB) with unusual histopathologic features characterized mainly by numerous aggregations of basaloid cells limited to the subcutis. The three trichoblastomas with unusual features were identified from a large series of 38 solitary TB cases collected over a period of 20 years. Clinically, all three neoplasms presented in men (49, 52, and 62 years old) as solitary, 1- to 1.5-cm skin-colored nodules situated on the scalp, face, and lower arm, respectively. Histopathologically, they showed numerous, smooth-bordered aggregations of basaloid cells limited to the subcutis and surrounded by a sclerotic and partly hyalinized stroma. Multiple sections revealed no connections of basaloid aggregations to the overlying epidermis or pre-existing follicular structures. All three cases displayed rather unusual morphologic growth patterns, including areas of variously sized, nodular aggregations of basaloid cells and extensive foci of elongated, thin columns and branching cords of basaloid cells. A striking feature in the stromal component in two cases was the presence of large, prominent areas of hyalinization and sclerosis. Characteristically, all three neoplasms showed numerous foci with rudimentary follicular germs and papillae. Cytomorphologically, the basaloid cells exhibited dark staining nuclei with large prominent nucleoli and scanty, pale or eosinophilic cytoplasm. Variable number of mitotic figures (2-4 mitoses per high-power field) and single necrotic cells were noted. In one case, small, foci of necrosis en masse were observed. Follow-up data after total excision in all three cases (80, 69, and 6 months) revealed no local recurrences. In light of our observations, we suggest that subcutaneous TB represents a rare variant of solitary TB. Besides the exclusive subcutaneous location, this neoplasm also displays a constellation of particular histopathologic features, namely, rather complex epithelial growth patterns and stroma with prominent foci of sclerosis and hyalinization.

CD56+ blastic transformation of chronic myeloid leukemia involving the skin.

We report on two patients with chronic myeloid leukemia (CML) who presented blastic transformation involving the skin, with leukemic infiltrates showing unusual morphologic and immunohistologic characteristics. Both patients were elderly men with a 36-month and a 40-month history of CML, respectively. They presented with disseminated, reddish to violaceous papules and plaques (case 1), and with localized reddish nodules on the left temporal area (case 2). Concurrent features of blastic transformation in the bone marrow were observed in one patient (case 1). Histopathologic examination of skin lesions revealed similar features in both cases. There was a moderate to dense dermal infiltrate composed mainly of medium-sized atypical mononuclear myeloid precursor cells with only few relatively well-differentiated cells of the granulocytic series. Histochemical staining for naphthol-ASD-chloroacetate esterase revealed strong positivity (>50% of neoplastic cells) in case 2 and only scattered positivity (< 10% of neoplastic cells) in case 1. Immunohistologic analysis performed on paraffin-embedded sections showed in both cases variable reactivity of neoplastic cells for leucocyte common antigen (CD45), lysozyme, myeloperoxidase, CD11c, CD15, CD43, CD66, CD68, HLA-DR, and the neural cell adhesion molecule (NCAM) CD56. A negative reaction was observed for CD3, CD34, and TdT. The immunohistologic findings were remarkably similar to those reported for acute myeloid leukemia (AML) with monocytic differentiation (French-American-British [FAB] classification, subtype M4). Examination of blasts from the bone marrow performed in one patient (case 1) revealed a similar phenotype also with CD56 expression. In conclusion, our observations show that specific cutaneous infiltrates in CML may show morphologic and immunohistochemical characteristics similar to those observed in AML with monocytic differentiation. Moreover, specific cutaneous manifestations of CML may express CD56.

Trichoblastoma and sebaceoma in nevus sebaceus.

We report two cases of an unusual combined adnexal neoplasm arising in a nevus sebaceus (NS). Clinically, both neoplasms presented in two women (46 and 78 years) as single, partially ulcerated nodules within NS situated on the scalp. Histopathologically, each neoplasm showed distinctive aggregations of basaloid cells with features of trichoblastoma adjacent to aggregations of neoplastic cells exhibiting features of sebaceoma. In both cases, typical features of NS were present. To the best of our knowledge, this unusual combined adnexal neoplasm comprised of trichoblastoma and sebaceoma could not be assigned to any previously described histopathologic entity. This "complex" adnexal neoplasm should be distinguished histopathologically from basal cell carcinoma with sebaceous differentiation and trichoblastoma with sebaceous differentiation.

Non-random spatial association of melanoma and naevi--a morphometric analysis.

Previous studies have shown that congenital as well as acquired melanocytic naevi indicate an increased risk for developing melanoma in individual patients. Most studies stress the importance of melanocytic naevi as melanoma markers, while in some studies they are considered to be direct melanoma precursors. The latter opinion is favoured by the common co-occurrence of melanoma and naevus within one biopsy. The present study examines the question of whether the co-occurrence of melanoma and naevus is a random event or whether melanomas significantly co-localize with pre-existent naevi, which would suggest a precursor role for these naevi. Seven hundred biopsies of primary melanoma were examined for the presence of congenital or acquired naevi according to standard histological criteria. A naevus was found in 143 of the 700 biopsies (20.4%), of which 90 were acquired (12.9%) and 53 were congenital (7.6%). Within each biopsy the exact location of the melanoma and the naevus was determined using an ocular micrometer at a final magnification of 20 x. From these data the frequency of finding a naevus with increasing distance from the melanoma margin was calculated. The frequency of finding a naevus decreased from 2.6% immediately at the melanoma border to 0.3% at a distance of 4.5 mm and 0% at a distance of 5.0 mm. This decrease was statistically highly significant (P<0.001). Similar results were obtained when congenital and acquired naevi were evaluated separately. These data strongly indicate that melanoma and naevi are non-randomly distributed and that both congenital and acquired naevi may be precursors of melanoma.

Specific cutaneous infiltrates in patients with myelogenous leukemia: a clinicopathologic study of 26 patients with assessment of diagnostic criteria.

BACKGROUND: Few recent studies have analyzed the clinicopathologic features of specific cutaneous manifestations of myelogenous leukemia in a large number of patients. OBJECTIVE: We characterize the clinical and histopathologic spectrum of specific cutaneous manifestations in acute (AML) and chronic (CML) myelogenous leukemia, ascertain further diagnostic criteria, and examine current prognosis. METHODS: Thirty-six lesions of specific cutaneous infiltrates from 26 patients with myelogenous leukemia (AML: 17 patients; M:F = 1:2.4; mean age: 52.6 years; AML-French-American-British [FAB] classification subtypes:M1 = 1, M2 = 3, M4 = 8, M5 = 5. CML = 9 patients; M:F = 4.5:1; mean age: 60.6 years) were retrospectively collected for the study. RESULTS: Cutaneous manifestations presented as solitary or multiple reddish to violaceous papules, plaques, and nodules (17 lesions), or as a generalized erythematous maculopapular eruption (9 lesions). Concurrent extramedullary involvement in other peripheral sites (eg, gums, pharynx, orbits) was observed in 10 patients. Histopathologically, lesions revealed nodular/diffuse infiltrates, often with perivascular and periadnexal accentuation, sparing of the upper papillary dermis, and prominent single arraying of neoplastic cells between collagen bundles. Extension to the subcutis was noted in all deep biopsy specimens (26 lesions). Cytomorphologically, medium to large-sized mononuclear cells (myeloblasts and atypical myelocytes) predominated in AML-M1 and M2, whereas M4 and M5 mainly showed small, medium-sized, or large mononuclear cells with slightly eosinophilic cytoplasm and indented, bi-lobular, or kidney-shaped nuclei (atypical monocytoid cells). In CML, either a variable mixture of mature and immature cells of the granulocytic series (myelocytes, metamyelocytes, eosinophilic metamyelocytes, and neutrophils) or a rather monomorphous infiltrate of mononuclear cells were found. Staining for naphthol AS-D chloroacetate-esterase (NASD) was positive in 24 of 36 lesions (66.6%; AML: 16; CML: 8). Immunohistochemical analysis on paraffin sections using a large panel of antibodies (16 lesions: AML: 13; CML: 3) showed strong reactivity for LCA (CD45), lysozyme, myeloperoxidase (MPD), LN2 (CD74), HLA-DR, and MT1 (CD43) in the majority of cases, and variable staining for monocyte/macrophage markers (KP1/CD68, PGM1/CD68, Mac387, Ki-M1p). The neuronal cell adhesion molecule (NCAM) marker CD56 was reactive in 2 cases of CML, but negative in all cases of AML. MIB1(Ki67) stained 20% to 80% of neoplastic cells. CD34, CD15, CD20, and CD3 were negative in all cases. No correlation between histochemical/immunohistochemical features with type of leukemia or FAB-subtype of AML was observed. All patients with CML and AML with adequate follow-up died within 24 months after onset of skin lesions (mean survival, AML: 7.6 months; CML: 9.4 months). CONCLUSION: Specific cutaneous lesions in AML and CML show distinctive clinicopathologic features that allow diagnosis in most cases. Immunohistochemistry on routinely fixed, paraffin-embedded tissue sections provides useful adjunctive information. Simultaneous expression of lysozyme, MPD, CD45, CD43, and CD74 militates in favor of a diagnosis of specific cutaneous infiltrate of myelogenous leukemia. Pitfalls in immunohistologic diagnosis mainly include lack of expression of some myeloid markers (lysozyme, MPD), and aberrant expression of T-cell markers (eg, CD45RO). Regardless of type of myelogenous leukemia, onset of specific skin manifestations correlates with an aggressive course and short survival.

Cutaneous leiomyosarcoma.

We report the clinical, histopathologic, immunohistologic, and prognostic findings in 19 patients with cutaneous leiomyosarcoma, eight males and 11 females (mean age, 66 years; age range, 41-93 years). The tumors presented mainly as solitary lesions and were located on the head and neck (eight lesions), trunk (four lesions), upper extremities (three lesions), and lower extremities (four lesions). Histopathologically, two predominant growth patterns were observed: nodular (12 cases) and diffuse (seven cases). Neoplasms with a nodular growth pattern were characterized by high cellularity and prominent nuclear atypia, and they showed conspicuous mitoses, several necrotic cells, and sometimes extensive necrotic areas. By contrast, most cutaneous leiomyosarcomas with a diffuse growth pattern revealed low cellularity, well-differentiated smooth muscle cells, inconspicuous mitotic figures, and few or no necrotic cells. Immunohistologic investigations revealed all cutaneous leiomyosarcomas to express vimentin and smooth muscle actin. Pan-muscle actin (HHF-35) was also expressed in most cases (15 lesions). However, only 12 lesions showed positive staining for desmin. Remarkable was the expression of cytokeratins in five lesions. Clinical follow-up revealed local recurrences in five patients (three cases with nodular pattern and two lesions with a diffuse pattern) after a period ranging from 8 months to 3 years after surgical excision. No distant metastases have been observed in our series. We conclude that cutaneous leiomyosarcoma with a diffuse growth pattern may constitute a pitfall in histopathologic diagnosis because of the presence of only subtle criteria for malignancy. Cutaneous leiomyosarcoma may show different immunophenotypes, thus emphasizing the importance of using a large panel of antibodies (smooth muscle actin, HHF-35, desmin, vimentin, cytokeratins, and S-100 protein) in immunohistologic diagnosis. Cutaneous leiomyosarcoma sometimes reveals local recurrences, but it has negligible potential for distant metastases.

Proliferating pilomatricoma. A histopathologic simulator of matrical carcinoma.

We report on 9 patients with pilomatricomas that showed unusual histopathologic features. Our patients were mainly elderly individuals (age range 42 to 88 years; mean age 70.1 years) who presented solitary cutaneous nodules situated on the head and neck (7 neoplasms), upper arm (1 neoplasm), and back (1 neoplasm). All the lesions were treated by simple excision. Follow-up data available in 7 of the 9 patients (mean follow-up, 17 months) revealed local recurrences in 1 patient whose lesion recurred 3 times. No lymph node involvement or distant metastases were recorded in any of our cases. Histopathologically, most neoplasms were characterized by a relatively large lesion in the dermis that in some cases showed extension to the subcutis. Each lesion was predominantly composed of a lobular proliferation of basaloid cells in association with adjacent focal areas containing eosinophilic, cornified material with shadow cells. In some cases, relatively large areas of shadow cells were present, whereas, in others only small foci of shadows cells were observed. Cytomorphologically, the basaloid cells showed features of matrical and supramatrical cells of a normal hair follicle and exhibited variable nuclear atypia and mitotic figures. The overall architectural pattern of the neoplasms was different from that of large fully developed stereotypical pilomatricomas that maintain a cystic character with basaloid cells predominantly aligned at the periphery. Based on the histopathologic findings, namely the presence of a large, lobular proliferation of basaloid cells in association with small to large foci of shadow cells, we interpreted these neoplasms to be a distinctive proliferative variant of pilomatricoma and propose the designation "proliferating pilomatricoma." Proliferating pilomatricomas should be differentiated from the recently described matricoma, basal-cell carcinoma with matrical differentiation, and matrical carcinoma (pilomatrical carcinoma).

[Reticular lentigo]. / Retikuläre Lentigo.

We studied the clinical and histopathologic features in five patients with reticulated lentigo. This peculiar pigmented skin lesions has previously been described under the designations "acquired reticulated lentigo", ink spot lentigo, "reticulated melanotic macule" or "reticulated lentigo". Each of the 4 males and 1 females in our study (age range: 16 to 57 years; mean age: 34 years) had a single, 4-6 mm large, black macule with irregular, fingerlike extensions at the periphery. All lesions were situated on the upper back and surrounded by numerous sun-induced freckles. Dermatoscopic examination revealed irregularly formed "meshes" and confirmed the reticulated pattern seen clinically. Reticulated lentigo presented mostly in individuals with skin type 1, red to blond hair, and blue eyes. The clinical diagnosis in 4 out of 5 cases was melanoma in situ. Histopathologically, reticulated lentigo was mainly characterized by a sharply circumscribed hyperpigmentation of the lower epidermis with accentuation at the tips of elongated and clubbed rete ridges. In addition, a normal or slightly increased melanocyte number in the basal layer and an infiltrate of melanophages in the upper dermis was noted. Reticulated lentigo shows histopathologic features similar to those of melanotic macules on volar skin and mucous membranes. Because of its characteristic clinical, dermatoscopic and histopathologic features reticulated lentigo can be regarded as a distinctive clinicopathologic entity.