[Malignant proliferative tricholemmal tumor: a clinical, morphologic and ultrastructural study]

The clinical, morphological and ultrastructural features of malignant proliferating Tricholemmal Tumor with neoplastic angioinvasion, and its histogenetic changes are discussed. We concluded that it is a tumour derived from non-keratogenous lower external tricholemmal sheath cells. We prefer the denomination of Malignant Proliferating Tricholemmal Tumour, instead of Malignant Proliferating Tricholemmal Cyst because, in our case, there was an important proportion of solid tumoral component beside the numerous cysts.