Adenocarcinomas, apocrineC44.L43

Malignant adnexal tumor with apocrine differentiation.

Axilla, anogenital region, more rarely breast, nipple, finger or capillitium.

Mostly solitary, clinically not very distinct lump with a diameter of 2-8 cm.

All adnexal carcinomas show the signs of malignancy such as asymmetry, blurred boundaries, invasive growth with destruction of local structures. A standard for the grading of adnexal carcinomas has not yet been developed. Remarkable is a variability in the extent of the cytological atypia. The tumor cells show positivity for cytokeratin, GCDFP-15, rarely for S100. They are CEA-negative.

Undifferentiated carcinomas have a poor prognosis; tendency to metastasize to the regional lymph nodes.

Malignant adnexal tumors of the skin with tubular or ductal differentiation are relatively rare. The individual observations which inevitably result from this have led to a widespread confusion regarding their diagnosis, classification and therapy. Adnexal carcinomas can develop de novo, but also in pre-existing benign tumours and hamartomas of the skin appendages. The classification of de novo developed undifferentiated adnexal carcinomas is often difficult. For example, the adenocarcinomas developing from a spiradenoma or a cylindrome usually lack any differentiation so that they could only be classified as poorly differentiated adenocarcinomas without the benign initial tumor. Their classification as an "eccrine adnexal carcinoma" is then not possible.