OBJECTIVETo study the clinicopathological features, immnophenotype and differential diagnosis of prepubertal-type vulva fibroma (PVF).

METHODClinical, radiological and pathological features of 2 cases of PVF were analyzed along with a literature review.

RESULTSBoth patients were females of 8.5 and 54 years of age, presented with recurrent unilateral mass at the labium major respectively. Grossly, cut surface of the tumor appeared as the gray fibrous tissue without any definited lump detected. Histologically, the ill-circumscribed lesion located predominantly in the deep dermis with an extension into the subcutaneous tissue. They had a low cell density consisting of scattered spindle shaped fibroblast-like cells and a large amount of collagen fiber matrix, nuclear atypia not seen and mitotic figures scanty. The tumor cells extended downward under the epithelium and infiltrated between the fat tissue, nerve fibers as well as the capillaries making a lesion looked somewhat like a harmatoma. Immunohistochemically, the spindle cells were uniformly positive for vimentin, weakly positive for CD34, and negative for alpha-smooth muscle actin (SMA), muscle specific actin (HHF35), desmin, h-caldesmon, CD99, S-100 protein, bcl-2, beta-catenin, estrogen and progesterone receptors.

CONCLUSIONSPVF is a benign mesenchymal lesion with a predilection of involving the vulva of prepubertal girls or adults in rare cases. PVF may represent an overgrowth of normal stromal tissue of vulva. Approximately one third of the tumors develop local recurrence due to incomplete excision, however, there is also occasionally spontaneous regression.