Malignant degeneration of pilonidal cysts.

Malignant degeneration is a rare occurrence in pilonidal disease. The authors present three new cases with a review of the world's previously published 41 cases. Among the total 44 cases, 36 were squamous cell carcinoma. All cases occurred in the setting of long-standing pilonidal disease, with the mean duration of antecedent disease being 23 years. Five of six patients presenting with inguinal metastases died within 16 months. Four patients received adjuvant radiation therapy, one received adjuvant chemotherapy, and one patient in the current series received both adjuvant chemotherapy and radiation. Six patients with recurrence underwent potentially curative resection, with three patients surviving greater than 10 years with no evidence of disease. The authors propose consideration of adjuvant chemotherapy and radiation as a new modality to decrease the local recurrence rate.