[A case of primary cutaneous PEComa]. / Un PECome cutané primitif.

BACKGROUND: PEComas (PEC: Perivascular epithelioid cell) are tumours expressing both melanocytic and myogenic markers. The clinical features are non-specific. PATIENTS AND METHODS: A 55-year-old woman presented with a non-specific tumour on her right arm. Histological examination revealed an intradermal tumour composed of clear epithelial cells. The tumour was positive for HMB45 and protein S100, and was negative for Melan-A and actin. A diagnosis of PEComa was retained despite negative myogenic markers. DISCUSSION: PEComas are neoplasms composed of nests and fascicles of clear to granular epithelioid cells that express both melanocytic markers (HMB45, Melan-A, NK1C3, tyrosinase) and myogenic markers (actin, caldesmin, desmin, calponin), whereas S100 protein and cytokeratins are usually absent. Included in this broad category are angiomyolipoma, clear-cell "sugar" tumours and lymphangioleiomyoma. Some deep PEComas may have a malignant course. Cutaneous primitive forms are exceptional and often benign. Histological differential diagnoses to consider are those of clear-cell tumours: paraganglioma-like dermal melanocytic tumour, melanoma, metastatic clear-cell renal carcinoma and epithelioid sarcoma. In our patient, a diagnosis of cutaneous primitive PEComa was retained despite the absence of myogenic markers and the positivity of the protein S100, based on the cytological and immunohistochemical features, which were not evocative of any other diagnosis. CONCLUSION: Cutaneous PEComa are non-specific tumours. Histological analysis confirms the diagnosis and allows other more aggressive tumours to be ruled out.

[Palmar fasciitis associated with polyarthralgia: rare paraneoplastic syndrome]. / Fasciite palmaire associée à des polyarthralgies: un syndrome paranéoplasique rare.

BACKGROUND: Palmar fasciitis associated with polyarthralgia is a rare paraneoplastic syndrome, frequently observed in women, and in most cases associated with ovarian carcinoma. CASE REPORT: A 51 year-old man complained of extensive palmar dermatological lesions associated with polyarthralgia of the legs. A few months earlier, cholangiocarcinoma had been diagnosed due to cholestatic icterus. The cutaneous biopsy confirmed the diagnosis of palmar fasciitis associated with polyarthralgia. DISCUSSION: This paraneoplastic syndrome is rarely described in digestive carcinoma and never in cholangiocarcinoma. The diagnosis is clinical, confirmed by certain laboratory exams. The evolution is similar to that of the carcinoma. Only curative treatment can achieve regression of the symptoms.