CLEAR-CELL POROCARCINOMA - ANOTHER CUTANEOUS MARKER OF DIABETES-MELLITUS

The relationship between clear-cell syringoma and diabetes mellitus is well established. We present a case of clear-cell porocarcinoma in a diabetic patient. The lesion consisted of a 5-cm nodule on the lateral aspect of the left leg. Histopathologically, the neoplasm was compose d of irregular aggregations of neoplastic cells with striking clear-ce ll appearance, showing features of ductal differentiation. The clear-c ell appearance of neoplastic cells was due to glycogen accumulation wi thin their cytoplasm. Immunohistochemistry and ultrastructural studies also supported the diagnosis of a neoplasm with sweat ductal differen tiation. Enzyme histochemical reactions for phosphorylase immunoreacti vity on fresh, unfixed sections of the neoplasm demonstrated that this immunoreactivity was remarkably decreased. Some adnexal neoplasms of the skin mostly composed of clear cells may be cutaneous markers of di abetes mellitus. Phosphorylase activity deficiency in diabetic patient s may be responsible for glycogen accumulation in neoplastic cells res ulting in clear-cell appearance of these neoplasms.