Alberto Alfaro Rubio, Hugo Vázquez-Veiga, Rafael Botella-Estrada, Irati Allende Markixana, Lucia Barchino, Pedro Rodríguez-Jiménez, Angeles Flórez-Menéndez, Alejandra Reolid, Pablo de la Cueva Dobao, Regesmohs, Natividad Cano-Martinez, Pedro Sánchez-Sambucety, J.R. Garcés, Pilar Gil, Ignacio García-Doval, Cristina Ciudad-Blanco, Pablo L. Ortiz-Romero, Roman Miñano Medrano, Maria J. Seoane‐Pose, Pedro Redondo, Ricardo Suarez Fernández, Matias Mayor Arenal, Beatriz García-Bracamonte, Eva Vilarrasa, Veronica Ruiz-Salas, Izascun Ocerin-Guerra, Juan L Artola-Igarza, L. Hueso, Esther de Eusebio-Murillo, María L A Pacheco, José L. López-Estebaranz, Lucia Carnero-González, O. Sanmartín-Jiménez, Manuel Ángel Rodríguez-Prieto, B. González-Sixto, Begoña Escutia-Muñoz, A. Toll-Abelló, Victoriano Morales-Gordillo, Yolanda Delgado Jiménez, and Miguel Ángel Descalzo
Background The use of Mohs micrographic surgery (MMS) for rare cutaneous tumors is poorly defined. We aim to describe the demographics, tumor presentation and topography, surgery characteristics and complications of MMS for rare cutaneous tumors in a national registry. Methods Prospective cohort study of patients treated with MMS in Spain between July 2013 and June 2018. The inclusion criteria were patients with cutaneous tumors with final diagnosis different from basal cell carcinoma, squamous cell carcinoma, dermatofibrosarcoma protuberans, or any kind of melanoma. Results Five thousand and ninety patients were recorded in the registry, from which only 73 tumors (1.4%) fulfilled the inclusion criteria: atypical fibroxanthoma (18), microcystic adnexal carcinoma (10), extramammary Paget's disease (7), Merkel cell carcinoma (5), dermatofibroma (4), trichilemmal carcinoma (4), desmoplastic trichoepithelioma (4), sebaceous carcinoma (3), leiomyosarcoma (2), porocarcinoma (2), angiosarcoma (2), trichoblastoma (1), superficial acral fibromyxoma (1), and others (10). No intra-surgery morbidity was registered. Postsurgery complications appeared in six patients (9%) and were considered mild. Median follow-up time was 0.9 years during which three Merkel cell carcinomas, one angiosarcoma, one microcystic adnexal carcinoma, and four others recurred (12.3%). Conclusion This national registry shows that rare cutaneous tumors represent a negligible part of the total MMS performed in our country with a low complication rate.