Chordoma cutis
We report a case of an 85-year-old white man with a diffuse form of psoriasis, who showed a large asymptomatic subcutaneous tumour in the sacrococcygeal region. On cut section there was a subcutaneous neoplasia with a glistening, friable surface. Histologically, the deep dermis was infiltrated by cords and nests of pleomorphic cells embedded in an abundant mucinous stroma, and characteristic physaliphorous (multivacuolated) cells were observed. The neoplastic cells were immunohistochemically positive for cytokeratins (using CAM 5.2 and AE1/AE3), vimentin, S100 protein, and epithelial membrane antigen (EMA), but negative for carcinoembryonic antigen (CEA). Histological and immunohistochemical findings led us to the diagnosis of classic chordoma. Chordomas are rare, slow growing malignant tumours of the spinal axis originating from remnants of the notochord. Occasionally, a skin lesion is the first sign of a primitive or metastatic chordoma.