Chronic Pilonidal Cyst with Malignant Transformation: A Case Report and Literature Review.

A 63-year-old male with a 20-year history of a chronic, recurrent sacrococcygeal pilonidal cyst was referred to our outpatient clinic. He had received multiple surgical resections in the past with benign pathology. He presented with a verrucous wart-like midline mass on the superior gluteal cleft that had grown since his last resection. The patient subsequently underwent resection of the mass with bilateral gluteal rotational flaps. Pathology showed squamous cell carcinoma with tumor-free margins, and further imaging showed no evidence of metastatic disease. It is believed chronic inflammation with subsequent genetic and impaired DNA repair mechanisms is the leading cause of malignancy. The treatment of choice for pilonidal carcinoma is surgical resection with free margins. Reconstruction methods can be utilized to repair the tissue defect. Pilonidal carcinoma has high mortality risk with surgical treatment yielding a disease-free 5-year survival rate of 55% of patients and a high recurrence rate of 50%. The role of chemoradiotherapy is currently unclear.