Two skin tumors with unusual features indicative of eccrine differentiation and behavior analogous to basal cell epitheliomas are described. The lesions were slowly growing, locally invasive, and destructive and one of them recurred many times. Pathology, histochemistry, and electron-microscopic studies indicate that these tumors are differentiating toward eccrine tissue. They satisfy the criteria for classification as basal cell epitheliomas with eccrine differentiation (eccrine epithelioma), a tumor entity not previously clearly defined.
Freeman RG, Winkelmann RK. Basal Cell Tumor With Eccrine Differentiation (Eccrine Epithelioma). Arch Dermatol. 1969;100(2):234-242. doi:10.1001/archderm.1969.01610260110021