Polymorphous sweat gland carcinoma is a rare adnexal tumour and usually presents as a slow growing dermal mass on an extremity. Local recurrence is not uncommon, particularly following incomplete surgical excisions. Metastasis is rare.
Histology of polymorphous sweat gland carcinoma
Polymorphous sweat gland carcinomas are dermally based tumours (figure 1) that show a wide range of morphologic growth patterns ranging from solid, tubular (figures 2, 3), cribriform (figure 4) and ductal. Abrupt transitions between morphologies is a characteristic feature (figure 5, 6).
Polymorphous sweat gland carcinoma pathology
Special studies for polymorphous sweat gland carcinoma
None are generally needed. Stains to exclude metastasis from another site can be helpful.
Differential diagnosis of polymorphous sweat gland carcinoma
Adenoid cystic carcinoma – Some areas may resemble adenoid cystic carcinoma but the multiple morphologies and absence of perineural invasion favours polymorphous sweat gland carcinoma.