[Malignant transformation in multiple eccrine spiradenoma]

Development of a poorly differentiated eccrine carcinoma was observed in a 6-year-old woman. She had been operated on many times during 20 years for some tens of classical as well as less usual forms of eccrine spiradenomas, e.g. giant vascular spiradenomas. They were mostly localized in the skin of back, thorax and neck. The patient died of an extensive skin involvement and spine and liver secondaries 12 months after occurrence of the carcinoma. The structure of carcinoma was trabecular and partly papillary, tumour cells had bulky nuclei and striking nucleoli. There was a juxtaposition of spiradenomas with carcinoma and direct transformation of spiradenoma into carcinoma was observed. Immunohistological positivity of carcinoma concerned S-100 protein, slightly CEA, focally cytokeratin 7 and 18; cytokeratin 14 was negative. Ultrastructure of tumour cells showed irregular intercellular lumina with some microvilli, but structures characteristical for eccrine glandular of ductal differentiation were lacking.