NCIthesaurus vulvar benign neoplasm vulvar nodular hidradenoma UMLS_CUI:C1520091 NCI:C40312 disease_ontology DOID:2060 A vulvar benign neoplasm that is characterized by nodules with cystic foci high in dermis on gross examination and derives_from the sweat gland distal excretory duct. Histologically characterized by nests or lobules of cells resembling eccrine poroma with either clear cytoplasm or prominent squamous metaplasia and lumina lined by cuboidal ductal cells or columnar secretory cells.