adnexal and skin appendage tumor basaloid follicular neoplasms MPATH:575 This is a new diagnostic term that the MMHC pathology panel felt best described a diagnostically challenging set of tumors that share the feature of being compose of basaloid cells showing follicular differentiation to some extent. These tumors are common in GEM involving the hedgehog signaling pathway and frequently have more than one of the histologic patterns listed below. The designation of benign and malignant has been excluded from the primary diagnosis purposely, as this is frequently difficult to determine in these characteristically well circumscribed tumors. The presence of a disorganized (non-palisaded) sheet-like growth pattern, tumor necrosis, or numerous mitoses are felt to represent malignant transformation. mouse_pathology.ontology