Factors in the surgical management of primary eccrine porocarcinoma: prognostic histological factors can guide the surgical procedure

Background Primary eccrine porocarcinoma is a rare cutaneous neoplasm and there is no consensus concerning its surgical management. Objectives To conduct a retrospective analysis of all the cases of eccrine porocarcinoma seen in our hospital in order to identify prognostic factors. Methods Clinical data were retrieved from the patients' files. Each histological sample was reviewed by the pathologist and classified into three eccrine porocarcinoma subtypes: 'infiltrative', 'pushing' and 'pagetoid' eccrine porocarcinoma, according to Robson's criteria. Statistical methods were used to estimate the recurrence risk. Results Twenty-four patients were included. The surgical margins realized were >= 2 cm or < 2 cm in six and 13 patients, respectively, and slow Mohs procedure was performed in two patients. Ten, seven and two patients presented with 'infiltrative', 'pushing' or 'pagetoid' eccrine porocarcinoma, respectively. Eight patients (of 23) experienced recurrences (35%). The recurrence risk was linked to the histological subtype: two out of two pagetoid eccrine porocarcinoma, four out of 10 'infiltrative' and none of seven 'pushing' eccrine porocarcinoma recurred (P = 0.026). The recurrence risk was not associated with epidermal growth factor receptor status, nor the margin realized. Conclusions The recurrence risk of 'pushing' eccrine porocarcinoma is significantly lower than for 'infiltrative' eccrine porocarcinoma. Based on these considerations, a decisional algorithm might be proposed: first step, excisional biopsy of the primary eccrine porocarcinoma and identification of the histological subtype; second step, infiltrative or pagetoid porocarcinoma should be excised with an additional modified micrographic Mohs procedure, while no additional surgery is needed for 'pushing' eccrine porocarcinoma if the first excisional biopsy is complete. Although demonstrated in a limited case series, the histological subtype might guide the surgical management of primary eccrine porocarcinoma.