Verrucous cutaneous sarcoidosis: case report and review of this unusual variant of cutaneous sarcoidosis.

Sarcoidosis is a multisystem disorder of unknown origin, characterized by the accumulation of lymphocytes and mononuclear histiocytes inducing the formation of noncaseating "naked" epithelioid granulomas. The lungs, lymphatic system, and skin are most often affected, but sarcoidosis may affect any organ. Cutaneous involvement of sarcoidosis is often the sentinel sign of the disease, with the skin sometimes being exclusively affected. We present a case of a 54-year-old African American woman with long-standing history of pulmonary sarcoidosis that presented with multiple verrucous cutaneous lesions on the upper and lower extremities mimicking carcinoma. The initial cutaneous biopsy was superficial in nature, and the pathologist raised the consideration of a possible keratoacanthoma. A deeper skin shave biopsy was performed, and the histopathology showed verrucous pseudoepitheliomatous epidermal hyperplasia with scattered noncaseating granulomas in the superficial dermis. Stains (acid-fast bacillus, Periodic acid-Schiff, and Gomori-Grocott methenamine silver stains) were negative for microorganisms. Given the clinical setting and histomorphology of the cutaneous lesions, the diagnosis of verrucous sarcoidosis was rendered. Verrucous sarcoidosis is a rare cutaneous manifestation of sarcoidosis that could be easily misdiagnosed if it is not appropriately biopsied. This hinders the precise evaluation of the histological specimen, overall clinical picture, and administration of appropriate therapy.

Immunolabeling pattern of podoplanin (d2-40) may distinguish basal cell carcinomas from trichoepitheliomas: a clinicopathologic and immunohistochemical study of 49 cases.

When the morphologic distinction between basal cell carcinomas (BCCs) and tichoepitheliomas is unclear, it poses a rare diagnostic challenge as the commonly defined histologic criterion is insufficient for differentiating these two neoplasms from each other. Their distinction is clinically important because the risk of progressive disease in BCC can be problematic, and trichoepitheliomas misinterpreted as BCC burdens the patient with an inaccurate diagnosis and consequential inappropriate surgery. Podoplanin (D2-40) is a well-known lymphatic endothelial surface marker that has been postulated to be upregulated in the outer root sheath of hair follicles and cutaneous neoplasms, such as adnexal tumors, squamous cell carcinomas, etc. We studied the expression of D2-40 by immunohistochemistry to determine if this marker could reliably differentiate these neoplasms from each other. A total of 49 cutaneous tumors, including 22 cases of trichoepitheliomas and 27 cases of BCC were examined. Of the 27 cases of BCC, 18 cases were located in the head and neck area, 5 on upper extremities, and 4 on the back. Of the 22 cases of trichoepitheliomas, all were from the head and neck area. D2-40 expression was present in 21/22 cases of trichoepitheliomas; 11 cases were diffusely positive (50%), 10 cases were focally positive (45.5%), and 1 case was negative (4.5%). D2-40 expression was present in 6/27 cases of BCC; 2 cases were diffusely positive (7.4%), 4 cases were focally positive (14.8%), and 21 cases were negative (77.8%). In summary, D2-40 expression was only weakly and focally positive in BCC (22.2% of cases) and diffusely and weakly positive in trichoepitheliomas (95.5% of cases). The sensitivity and specificity of D2-40 immunoreactivity to separate trichoepitheliomas from BCCs was 95.5% and 77.8%, respectively. This data suggests that D2-40 expression could be a useful potential marker to distinguish BCCs from trichoepitheliomas, especially when there is a high index of histologic suspicion for either of these two tumors. Our results also suggest that BCC can show differentiation toward the outer root sheath of hair follicles.

Merkel cell tumor in a trichilemmal cyst: collision or association?

An 86-year-old white male presented with an erythematous, painless, slowly growing, and firm left thigh nodule. Histologic examination revealed a dermal proliferation of monomorphous cells arranged in trabeculae, nests, and sheets with an infiltrative growth pattern. The cells had a high nuclear-cytoplasmic ratio, finely granular nuclear chromatin, and nuclear molding. Numerous mitotic figures, apoptotic cells, and individual cell necrosis were present; lymphovascular invasion was identified. The tumor was attached, demonstrating pagetoid intraepithelial migration, to a follicular cyst lined by squamous epithelium, lacking a granular cell layer and filled with compact keratinous content, diagnostic of trichilemmal cyst. Immunohistochemical study revealed that tumor cells expressed pan-cytokeratin (CK), chromogranin, synaptophysin, neuron-specific enolase, and CK20 (dotlike staining pattern), thus supporting the diagnosis of Merkel cell carcinoma. The association of Merkel cell carcinoma with a cyst is an exceptionally rare occurrence. As a result of the prominent involvement of the cyst wall by tumor cells, we favor that in this case carcinoma arose in the trichilemmal cyst rather than being a collision tumor. This hypothesis is also supported by the recent observation that Merkel cells are frequently present within normal hair follicles, especially in the isthmic portion that corresponds with the area of origin of the trichilemmal cyst.

Fine-needle aspiration of subcutaneous panniculitis-like T-cell lymphoma.

We report the fine-needle aspiration (FNA) cytology findings of Subcutaneous Panniculitis-like T-cell Lymphoma (SCPTCL) in a 66-year-old woman who presented with a four month history of asymptomatic subcutaneous nodules on her right chest wall and back. An excisional biopsy of the right chest nodules was performed, and the diagnosis of SCPTCL was rendered. On a follow-up visit, several skin lesions were noted throughout her body. A fine-needle aspiration (FNA) of the right inguinal region was performed. The FNA yielded cellular smears, composed mainly of sheets of epithelioid histiocytes and scattered multinucleated cells. However, no distinct granulomas were noted. The background of the cytological smears showed scattered atypical lymphoid cells, some of which displayed nuclear membrane irregularities. To the best of our knowledge, the cytological features on FNA material of SCPTCL have not been described.