Cutaneous sebaceous tumours and Lynch syndrome: long-term follow-up of 60 patients.

Background Sebaceous neoplasms (SN) may appear sporadically in the general population but may also be part of the Muir-Torre variant of Lynch syndrome (MT-LS). There are few studies in southern Europe on the incidence of MT-LS in the population of patients with SN. Aim To retrospectively review patients with SN and to analyse their clinical features and the incidence of MT-LS. Methods Patients with SN diagnosed between 1995 and 2015 were enrolled in the study. The diagnosis of MT-LS was made according to established clinical criteria and, whenever possible, was confirmed by germline mutation analysis. Results In 60 patients (32 men, 28 women, mean age 69.22 years), 96 SN were diagnosed: 65 adenomas (67.7%), 16 sebaceomas (16.7%) and 15 carcinomas (15.6%). Of the 60 patients, 50 (83.3%) had a single SN and 10 (16.7%) had multiple lesions. Patients diagnosed with MT-LS (12 patients, 20%) were younger (63.25 years vs. 70.71 years), and had a higher incidence of extrafacial SN (4/12 patients, 33.3%), and were significantly (P < 0.001) more likely to have multiple SNs (8/12, 75%) and keratoacanthomas (KAs) (6/12, 50%). Conclusion Our study confirms that all patients with SN should be investigated, as 20% of our patients were diagnosed with MT-LS. The most specific features of SN associated with MT-LS in our study were the presence of multiple lesions and association with KAs.