Exantema, fiebre y artralgias en una embarazada / Exanthema, fever and arthralgia in a pregnant woman

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Clear Cell Atypical Fibroxanthoma: Clinicopathological Study of 6 Cases and Review of the Literature With Special Emphasis on the Differential Diagnosis.

Atypical fibroxanthoma (AFX) is an uncommon dermal-based neoplasm arising on the sun-damaged skin of elderly people. Clear cell AFX is a rare variant with only 12 cases reported until the present date, all of them as case reports, except for 1 small series of 3 cases. The authors report 6 new cases and review the literature with special emphasis on the differential diagnosis. The clear cell variant represents 5% of AFX from their files. Histopathologically, it consists of sheets of epithelioid, pleomorphic cells, intermixed with a varying number of giant multinucleated and spindle cells, the latter arranged in a fascicular pattern. All cell types predominantly exhibit a clear, microvacuolated cytoplasm with well-demarcated cell borders. The clinical and immunohistochemical features of this variant are similar to those of the classic type. Clear cell AFX must be differentiated from other cutaneous clear cell neoplasms, some of them with an aggressive clinical behavior, including clear cell melanoma, primary cutaneous and metastatic clear cell carcinomas, clear cell sarcoma, pleomorphic liposarcoma, tumor of perivascular epithelioid cells, and distinctive dermal clear cell mesenchymal neoplasm. The clinical presentation and immunohistochemical profile play a key role in the differential diagnosis.

Fibromyxoid nephrogenic adenoma protruding in a renal cortical cyst. A rare morphological variant in an outstanding location.

Nephrogenic adenoma (NA) is an unusual, benign lesion of the urinary tract, generally presenting in the bladder and with less frequency in the renal pelvis, urethra or ureter. It consists of tubules, microcysts and papillae lined by a single layer of low cuboidal epithelium without atypia. Recently, a fibromyxoid variant mimicking an infiltrating mucinous adenocarcinoma has been described. We report hereby the case of a 70-year-old female with a fibromixoid NA protruding in a renal cortical cyst. Only one case of NA in a renal cortical cyst has been found in the literature and it was of the classical type. The development of a NA in a renal cortical cyst lends support to the theory that the NA results from proliferation of secondarily implanted exfoliated renal epithelial cells.

Perineal nodular induration ("Biker's nodule"): report of two cases with fine-needle aspiration cytology and immunohistochemical study.

Perineal nodular induration (PNI) is a fibroblastic pseudotumor that presents almost exclusively in male cyclists. It develops in the soft tissues of the perineum immediately posterior to the scrotum, as a bilateral or single, central or lateralized mass. Although well known to sport medicine specialists, it is a scarcely documented entity in the pathology literature. We present 2 cases of PNI with fine-needle aspiration cytology and immunohistochemistry. They consisted of a paucicellular fibroblastic proliferation containing CD34-reactive spindle and epithelioid cells, small foci of fibrinoid degeneration, numerous blood vessels, and entrapped groups of mature fat cells. Our cases show that the histopathological features of PNI are more varied than those previously described and its immunohistochemical profile is wider. A central cystic focus and a zonal pattern are not consistent features of this entity. The lesional cells can express CD34, a hitherto unreported immunohistochemical finding.