Iván Couto-González, Plastic and Reconstructive Surgery Service, Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Francisco J. González-Rodríguez, General Surgery and Digestive System Service. Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Ignacio Vila, Plastic and Reconstructive Surgery Service, Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Beatriz Brea-García, Plastic and Reconstructive Surgery Service, Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Luís García-Vallejo, General Surgery and Digestive System Service. Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Santiago Soldevila-Guilera, Plastic and Reconstructive Surgery Service, Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Javier Baltar-Boileve, General Surgery and Digestive System Service. Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain Antonio Taboada-Suárez, Plastic and Reconstructive Surgery Service, Complexo Hospitalario Universitario de Santiago de Compostela, A Coruña, Spain


Introduction: Neoplastic degeneration is an uncommon but extremely serious complication of pilonidal sinus (PS) disease. We pretend to determine the factors that influence in the prognosis of the neoplastic disease assessing clinical features and histological findings. Materials and Methods: We retrospectively studied the patients diagnosed of malignization of PS in our institution from 2000 to 2019. Results: Seven male patients with a mean age at diagnosis of 64.8 years old were collected. Average time between the initial symptoms of PS disease and the tumor diagnosis was 33.7 years. The patients presenting an ulcerative pattern in the primary tumor showed in all the cases perineural invasion, local deep structures infiltration, and neoplastic dissemination to the regional lymph nodes. All these patients died in an average time of 7 months. On the other hand, patients with exophytic patterns in the primary tumor did not present local invasion or regional nodes affectation. All the cases survive with an average follow-up of 70.5 months. Conclusions: Ulcerated lesions clearly show a worse prognosis than tumors with exophytic morphology. Factors as perineural infiltration, local deep structures infiltration, or regional lymph node involvement dramatically decrease survival rates.



Keywords: Pilonidal sinus. Squamous cell carcinoma. Malignant transformation.