Malignant Eccrine Poroma (Eccrine Porocarcinoma)

Overview

Introduction.
Malignant eccrine poroma, also called eccrine porocarcinoma, is a rare tumour ofthe dermal adnexa, derived from the acrosyringial duct of sweat glands. Historically it has been classified among a heterogenous group of adnexal skin tumours. It most probably originates froma pre-existing benign lesion (eccrine poroma) as against othermalignant tumours of the sweat glandswhich appear malignant from the start.Material and methods. The authors diagnosed a malignant skin lesion on the forehead 12x 12 cmin the fronto-temporal region. Within a period of two years it was the third surgical intervention,each time at a different facility. Preceding histology gave evidence of a spinocellular carcinoma. Thelesion underwent radiotherapy, however, it recurred and grewlarger.Biopsymaterial was examinedwith the aid of classical staining methods and a wide array of immunohistochemical methods.Consequently, plastic surgery was performed - transplantation of skin from the patient’s thigh to theexcised part of her face and head.Results. The tumour was made up of solid nests of atypical cells that in places contained abruptkeratinization, elsewhere in the form of narrow ducts in places with two layers of epithelium. Thetumour parenchyma was buried in a denser, even hyalinized tumour stroma and infiltrated theepidermis as well as the dermis. Immunohistochemically the cells displayed CEA, EMA, Ck 18, 19,singularly containing a PAS-positive substance. Sialomucins were absent. On the basis of the resultspresented, the authors diagnosed a malignant tumour stemming from the acrosyringium, mostprobably an eccrine poroma.Conclusion. A rare malignant tumour of the skin has been described and discussed were thesubtyping of tumours of the dermal adnexa, the histomorphology and immunohistology of the sweatglands, as well as the differential diagnostics of malignant eccrine poroma.

Key words:
malignant eccrine poroma - immunohistochemical examination - CEA, EMA, Ck 18, 19- differential diagnosis