[Epidermotropic eccrine carcinoma. Apropos of a case with ultrastructural examination]

Pinkus and Mehregan's epidermotropic eccrine carcinoma shows particular clinico-pathological characteristics which makes it different from the other cutaneous epitheliomas. A case observed on a 81 year old woman is reported. The initial lesion consisted of an ulcerating tumor on the calf, then followed by multiple verrucous papules eruption around it. Within a few weeks, many other verrucous tumors occurred on the upper part of the leg while a lymphedema was developing. One year after the initial lesion has been noticed, the patient died of metastases in distant organs. From a histological point of view, the tumor corresponded to a squamous cell carcinoma that was slightly keratinizing, Bowenoïd epidermotropic, with dermal involvement too. Features of duct formation were identified within solid nests of neoplastic cells, tumor emboli were seen in the lymphatics. The ultra-structural study made it evident that the tonofilaments were precarious in neoplastic cells; the cytoplasm contained glycogen. The inter-cellular bridges and desmosomes were scanty and micro-villi were noted. The latter confirm the sudoral nature of these cells. For Pinkus and Mehregan, this type of tumor originates in the acrosyringium, but we think that a contiguous segment of the sudoral duct must also be probably concerned. The spreading of the epidermotropic eccrine carcinoma occurs in the teguments themselves in a uncommon way. The tumor re-appears from the dermal lymphatic channels. The lymphatic involvement is the main characteristic of this cutaneous carcinoma, verified by metastases existing in distant organs.