A case of pseudovascular adenoid squamous cell carcinoma of the skin with spindle cell pattern.

We report a case of pseudovascular adenoid squamous cell carcinoma which was in the form of a dome-shaped, cherry red tumor on the right cheek of an 86-year-old Japanese woman. Histologically, two types of atypical cells were identified; round cells in the upper part and spindle cells in the lower part. In the upper part, inter-anastomosing sinusoid-like pseudolumina were observed between the cords of the tumor cells. Immunohistochemically, the tumor cells did not express Factor VIII-related and CD34 antigens or bind Ulex europaes I agglutinin, except for only one anti-cytokeratin antibody. Ultrastructurally, the tumor cells contained tonofilaments and desmosomes and represented acantholysis. From the electron microscopy, possible role of capillary hyperpermeability on the acantholytic process of the neoplastic cells was suggested.