While BHD syndrome is frequently associated with cutaneous fibrofolliculomas, oncocytic renal tumors, and lung cysts, an increasing number of somatic FLCN alterations have been identified in a range of tumors, including parathyroid adenomas and carcinomas, salivary gland oncocytomas, lung adenocarcinomas, basal-like breast cancers, malignant PEComas, and colorectal adenocarcinomas, among others [8,9,13,14,15,16,17,18,19,20]. This evidence concerns the gene FLCN and Birt-Hogg-Dubé syndrome.