The diagnosis of CAF generally depends on its typical location in vulva-vaginal and inguinal-scrotal areas, spindle-shaped cell histopathology, tumor cell expressions of marker proteins, and absence of one of the two RP1 genes. CAF can be hard to distinguish from two other spindle-shaped cell tumors, myofibroblastoma and spindle cell lipoma, that commonly also contain tumors cells with deletions in one of their two RF1 genes. The characteristic hyalinized blood vessels and the presence of CD34 protein-expressing and desmin protein-expressing cells in CAF help to distinguish it from myofibroblastoma. Unlike CAF, spindle cell lipomas seldom contain desmin protein-expressing or progesterone receptor-expressing tumor cells and commonly contain CD99- and S100-expressing proteins. In addition, spindle cell lipomas are rare in the vulvovaginal region and their tumor vasculature consists of capillary-sized, thin-walled blood vessels while those of CAF consist of more numerous blood vessels with thick, hyalinized walls. CAR and angiomyofibroblastoma can be difficult to distinguish from one another but angiomyofibroblastoma tumor cells show no alterations in their RB1 and FOXO1 genes.
Cellular angiofibroma
Angiofibroma
Fibroma
Collagenous fibroma
Juvenile hyaline fibromatosis
Littoral cell angioma
Sclerotic fibroma
Angiokeratoma