Plaque-Like Dermatofibroma: Case Report of a Rare Entity.

A case of a well-demarcated plaque measuring 11 cm without satellites of several years' duration is presented. It showed typical histologic findings of dermatofibroma, prompting a diagnosis of plaque-like dermatofibroma. The relationship to multiple clustered dermatofibromas and plaque-like myofibroblastic tumor is discussed.

Digital mucous cyst: Altered epidermal mucin as a clue to diagnosis.

BACKGROUND: Digital mucous cyst (DMC) is histopathologically characterized by accumulation of mucin in the dermis. Some cases of DMC also show epidermal mucin, the histopathologic appearance and staining properties of which have not been described in detail. METHODS: A total of 24 cases of DMC were investigated by routine hematoxylin-eosin (H&E) and Alcian blue stains in addition to AE1/AE3 immunohistochemistry. RESULTS: Nine out of the 24 cases of DMC showed epidermal mucin. As the epidermal mucin migrates upward within the epidermis, it transforms from a flocculent granular substance into one or several solid horizontal plugs with a more homogeneous appearance and incorporates cytoplasmic fragments of keratinocytes/corneocytes. The homogeneous mucin plugs stain eosinophilic or amphophilic with an H&E formulation using hematoxylin 7212 and basophilic with Gill 3 or Harris's hematoxylin. The eosinophilic staining is enhanced when the eosin solution contains phloxine. CONCLUSIONS: The variably eosinophilic, amphophilic, or basophilic staining of epidermal mucin can be explained by its composition of basophilic mucin and eosinophilic debris from cytoplasmic fragments. The eosinophilic staining of mucin has not been reported before and can be diagnostically important because it may be mistaken for serum exudate.

Accessory tragus: Report of a case in a rare location on the nasal vestibule.

A case of an accessory tragus located on the nasal vestibule is reported. This represents the third case of this entity located outside of a derivative of a branchial arch. All three of these cases were located in the nose/glabella region.

Superficial primitive neuroectodermal tumor/Ewing sarcoma (PN/ES): same tumor as deep PN/ES or new entity?

Primitive neuroectodermal tumor/Ewing sarcoma (PN/ES) is a single clinical, morphologic, and molecular small round cell tumor entity. These are generally found in deep soft tissue or bone of young male patients, with poor behavior. Location in dermis is unexpected; only rare cases are reported. Cases coded as "dermal," "cutaneous," or "skin" PN/ES were retrieved from our consultation files. Only primary dermal cases were included. Those otherwise diagnosed or with incomplete material were excluded. There were 13 dermal PN/ES cases, consisting of 10 women and 3 men. Ages ranged from 2 to 67 years (mean, 28 years). Locations included groin or thigh (4), back or shoulder (3), neck (1), chest (1), scalp (1), forehead (1), hand (1), and foot (1). Most cases were small (0.5-2.3 centimeters) and painful, and persisted for less than 1 year. All were located within the dermis. Three caused pedunculation; 9 also involved superficial subcutis. All but 1 of the metastasizing tumors were round and encapsulated. All were composed of round to oval cells with a vague rosetting pattern, slightly overlapping nuclei, finely stippled chromatin, clear to eosinophilic cytoplasm, and collagenous stroma. Median mitotic activity was 8 per 10 high-power fields. Necrosis was present in three cases. All had globular periodic acid Schiff positivity and distinctive cytoplasmic membrane CD99 reactivity. One case studied was positive for Fli-1. All were negative for leukocyte common antigen, Tdt, CD3, CD20, CD79, CK20, pankeratin, epithelial membrane antigen, chromogranin, neurofilament protein, carcinoembryonic antigen, desmin, actin, diffuse S100 protein, and HMB45. Nine cases with material for reverse transcription-polymerase chain reaction revealed 1 positive type 2 translocation (EWS exon 7 to Fli-1 exon 5), 4 negative, and 4 "unable to amplify." Treatment was by wide excision; 9 received chemotherapy and 6 radiation. Follow-up of 11 (85%) cases revealed the following: 1 metastasis to stomach and death at 3 years; 10 years without disease (median, 9.0 years). Cutaneous PN/ES is a superficial round cell tumor in older women, with better prognosis than deep PN/ES. These may have a hitherto unrecognized variant genetic abnormality.

Actinic keratoses and the incidence of occult squamous cell carcinoma: a clinical-histopathologic correlation.

BACKGROUND: The ability to clinically diagnose actinic keratoses (AKs) lesions has been taken for granted for some time. The importance of the malignant potential of these lesions is well known. However, a recent Phase IV, multicenter study assessing the long-term benefit of aminolevulinic acid-based photodynamic therapy provided a unique opportunity to prospectively examine the clinical histopathologic correlation of AKs. OBJECTIVE: The objective was to characterize the histopathology of clinically diagnosed AK lesions in the study population. METHODS: Punch biopsies of 220 clinically diagnosed untreated AKs were performed at baseline plus 51 lesions unresponsive to treatment (total, 271). RESULTS: Clinical diagnosis and histopathologic findings agreed in 91% (246/271) of the lesions biopsied. The balance of the biopsied lesions were: (1) benign changes 4% (11/271) and (2) occult cutaneous malignancy in 5% (14/271) of the cases, 12 squamous cell carcinomas and 2 basal cell carcinomas. CONCLUSIONS: In this study, about 1 in 25 clinically diagnosed AK lesions identified by board-certified dermatologist investigator(s) were occult early-stage squamous cell carcinomas on histologic assessment, a fact surmised by the medical community that until now had not been well quantified. These findings should be considered when clinicians decide how to treat and manage AK patients.

PsEma--a hitherto unnamed dermatologic entity with clinical features of both psoriasis and eczema.

INTRODUCTION: Recent advances in molecular biology have helped establish differences between psoriasis and a group of inflammatory skin disorders commonly referred to as eczema. The authors have observed significant overlap between these two conditions such that a distinction between them may not always be made, even with histologic examination of skin biopsy specimens. OBJECTIVE: To determine how frequently psoriasis patients present features of both psoriasis and eczema. METHODS: The authors conducted a prospective analysis of 100 consecutive psoriasis patients in their clinic. RESULTS: The authors found that 20% could be diagnosed as "intermediate," having lesions with characteristics of both psoriasis and eczema, or a personal history of both. The authors suggest naming this category of inflammatory dermatosis "PsEma"--an overlap condition in which the clinical, histologic, molecular, biologic, and therapeutic responses show characteristics of both psoriasis and eczema.

Interstitial heparan sulfate in granulomatous inflammatory skin diseases.

BACKGROUND: Heparan sulfate (HS) is a glycosaminoglycan that is anchored to the outside of cell membranes. Under ordinary circumstances, it is not present in the interstitium, but under certain circumstances, mainly in the setting of inflammation and tissue repair, HS can be shed from the cell surface into the interstitium in a regulated fashion. Under these circumstances, interstitial HS seems to have an immunomodulatory function because of its binding of many cytokines. However, it is not known which cell types present at an inflammatory site are responsible for this shedding. OBJECTIVE: We have investigated the presence of interstitial HS by immunohistochemistry in various inflammatory skin diseases characterized by different compositions of the inflammatory infiltrate. RESULTS: Strong interstitial HS immunoreactivity was present only in diseases with a predominantly histiocytic infiltrate but not in diseases with a predominantly lymphocytic or neutrophilic infiltrate. CONCLUSIONS: This indicates that histiocytes have a direct or indirect role in the HS shedding process. In the well-formed granulomas of sarcoidosis, interstitial HS immunoreactivity was spatially associated with the fibrotic ring at the periphery of the granulomas, but not with the center harboring the histiocytes. This suggests that histiocytes can stimulate fibroblasts to shed HS into the interstitium.

Buschke-Ollendorff syndrome: report of a case and interpretation of the clinical phenotype as a type 2 segmental manifestation of an autosomal dominant skin disease.

Buschke-Ollendorff syndrome is a rare, autosomal dominant disease consisting of osteopoikilosis and skin manifestations. A case is reported, and the literature is reviewed with special reference to the clinical distribution patterns of skin lesions. The 2 main types of skin manifestations in this entity are widely disseminated, symmetrically distributed papules and localized, asymmetrically distributed plaques. Both types of lesions have been observed within the same family or within the same person. This particular phenotype can be explained by type 2 segmental manifestation of an autosomal dominant cutaneous trait: Symmetrically distributed papules are a manifestation of the heterozygous state acquired by inheritance, and asymmetrically distributed plaques develop in areas that have undergone a somatic mutational event of the wild-type allele at an early developmental stage, the result being loss of heterozygosity.

Abundance of interstitial heparan sulfate in granuloma annulare but not in other mucinous skin diseases.

BACKGROUND: Heparan sulfate (HS), unlike other glycosaminoglycans, is mainly located on cell surfaces but can be shed into the interstitium by a regulated process. It has been found in interstitial fluid drained from cutaneous wounds, but otherwise the conditions under which the release of HS from the cell surface occurs are unknown. To better characterize this process, we have investigated the presence of interstitial HS in various skin diseases with glycosaminoglycan accumulation. METHODS: Histologic routine material was stained immunohistochemically using an antibody recognizing HS. RESULTS: Heparan sulfate immunoreactivity is present in the interstitium of young cutaneous scars and in the interstitium of the inflammatory infiltrate of granuloma annulare. No reactivity was found in a number of non-inflammatory skin diseases with mucin deposition. CONCLUSIONS: The selective presence of interstitial HS in only two of the investigated skin conditions supports the existence of a regulated mechanism to release HS from the surface of cells into the interstitium. It is suggested that HS modulates the biologic actions of growth factors and cytokines not only during wound repair but possibly also in inflammatory skin diseases such as granuloma annulare.