Vulvar angiomyofibroblastoma--a case report of rare entity mimicking Bartholin cyst

Vulvar angiomyofibroblastoma is rare tumor of obscure histological origin. Here a case of 49-year old woman is described with this intriguing benign vulvar entity. The tumor developed at left vulvar labia and clinically imitated Bartholin cyst with clinical complaints of regional discomfort without pain. A macroscopic evaluation revealed well separated, encapsulated tumor of 3,5 cm in diameter. On cut surface the tumor was whitish, flesh, solid with myxoid appearance without any apparent cysts formation. There were alternating hypo- and hypercellular in the neoplasm. Microscopically the tumor comprised proliferation of small thin walled vessels that were surrounded with cuffs and islands of epithelioid, spindle and plasmacytoid cells with occasional vacuolization. Some aggregations of cells were quite dense and in such fields, vessels were compressed and ecstatic enough to mimic a bit haemangiopericytoma pattern. A production of myxoid intercellular matrix was seen in loose, hypocellular areas and was confirmed by positive pas-alcian blue stain that demonstrated prominent myxoid stroma and intracytoplasmatic globules of acid glicoproteins. The immunoprofile was remarkable enough to show strong expression of vimentin and desmin, while there was a lack of pan-keratin (CKAE1/3) and smooth muscle actin (SMA) immunoreactivities. Such an immunofentype is regarded to share some of myofibrolastic origin despite SMA negativity. Tumor cells seemed to sprout from perivascular regions giving an impression of accumulations strictly associated with neighbouring vascular branches. This configuration of cells is very often viewed as pericyte-like proliferation. Thus, our case of angiomyofibroblastoma is an example of tumor that probably derives from perivascular stem cells that acquire some of myoid features.