The role of immunohistochemistry in discriminating primary from secondary extramammary Paget disease.

Background: Extramammary Paget disease (EMPD) is categorized into 2 groups: primary EMPD or EMPD secondary to underlying malignancy. Primary EMPD has a better prognosis, and the ability to distinguish between the 2 subsets has clinical relevance. Recent studies have suggested that immunostains, including cytokeratin (CK) 7, CK20, and BRST-2, distinguish between the 2 groups.

Pseudolymphomatous reaction to varicella zoster virus vaccination: role of viral in situ hybridization.

Herpes zoster (shingles) is the result of a reactivation of the varicella zoster virus (VZV). Many adults obtain a VZV vaccine in order to prevent zoster. Non-specific injection site reactions and generalized herpes eruptions have been reported to occur, especially in immunocompromised patients.

INI1 and GLUT-1 expression in epithelioid sarcoma and its cutaneous neoplastic and nonneoplastic mimics.

The morphological features of epithelioid sarcoma may closely mimic those of epithelial neoplasms, such as squamous cell carcinoma, mesenchymal tumors, such as benign fibrous histiocytoma, and nonneoplastic lesions, such as granuloma annulare. Immunohistochemistry, particularly for epithelial markers and CD34, thus plays a valuable role in the differential diagnosis of epithelioid sarcoma. However, some epithelioid sarcomas may show very focal or even absent expression of such markers and may be difficult to distinguish from various morphological mimics.

Necrobiotic xanthogranuloma: a review of 17 cases with emphasis on clinical and pathologic correlation.

Objective: To identify correlations between clinical presentation, specific histopathologic findings, and subsequent disease course in patients with necrobiotic xanthogranuloma (NXG).

Design: Retrospective review of medical records and histopathologic examination of fixed tissue samples.

Setting: Tertiary care medical center.

Gains of COL1A1-PDGFB genomic copies occur in fibrosarcomatous transformation of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans is a superficial low-grade sarcoma that rarely evolves into a high-grade fibrosarcoma. Dermatofibrosarcoma protuberans is genetically characterized by the unbalanced chromosomal t(17;22)(q21;q13), usually in the form of a supernumerary ring chromosome. The product of this chromosomal translocation is the chimeric gene COL1A1-PDGFB (collagen type I alpha I-platelet-derived growth factor beta), which is amplified at low levels in the ring chromosome.

In situ hybridization in cutaneous deep fungal infections: a valuable diagnostic adjunct to fungal morphology and tissue cultures.

Dimorphic fungal infections (histoplasmosis, blastomycosis, coccidioidomycosis, and cryptococcosis) can occur in immunocompromised and healthy individuals. Cutaneous involvement is often secondary and may be the presenting sign of systemic disease. These ominous infections are frequently clinically indistinct, and patient prognosis is influenced by a timely diagnosis and treatment.

The prognostic significance of fibrosarcomatous transformation in dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a superficial tumor characterized by high rates of local recurrence and a small risk of metastasis. Fibrosarcomatous (FS) areas rarely arise in DFSP, and considerable controversy exists as to whether these tumors have a higher risk of metastasis than the typical DFSP. The aim of this study was to reappraise the prognostic significance of FS changes in DFSP by analyzing 41 patients from the consultation files of our institution.

Adenocarcinoma of mammary-like glands of the vulva: Report of a case and review of the literature.

Mammary-like glands are a poorly recognized structure of normal vulvar skin. Adenocarcinomas arising from these glands are rare and represent a distinct clinicopathologic entity that must be distinguished from metastatic tumors. We reviewed 19 cases reported in the literature and describe a 51-year-old patient with a long-standing nodule on her right interlabial sulcus.

Malignant melanoma with a rhabdoid phenotype: histologic, immunohistochemical, and ultrastructural study of a case and review of the literature.

Malignant melanoma is known to display tremendous histologic diversity. One rare variant is the rhabdoid phenotype, so called because of the appearance of cells resembling rhabdomyoblasts seen in malignant rhabdoid tumors of the kidney. We present the histologic, immunohistochemical, and ultrastructural features of a malignant melanoma composed entirely of rhabdoid cells.

Cystic sebaceous neoplasms in Muir-Torre syndrome.

Cystic sebaceous neoplasms have been seen only in patients with Muir-Torre syndrome (MTS) and have recently been characterized as marker lesions of MTS. Histologically, these lesions form a spectrum of tumors ranging from benign cystic adenomas to proliferative cystic sebaceous tumors. We describe 2 proliferative cystic sebaceous tumors in a 53-year-old man whose workup revealed colonic adenocarcinoma and other sebaceous tumors consistent with MTS.

Substrate binding determinants of Trypanosoma brucei gamma-glutamylcysteine synthetase.

gamma-Glutamylcysteine synthetase (gamma-GCS) catalyzes the ATP-dependent ligation of L-Glu and L-Cys, which is the first step in de novo biosynthesis of the tripeptide glutathione. Recently it was demonstrated that gamma-GCS is a structural homologue of glutamine synthetase (GS), providing the basis to build a model for the gamma-GCS active site [Abbott et al. (2001) J.