Angiomyofibroblastoma (AMFB) is a benign tumor that belongs to the category of the "stromal tumors of the lower female genital tract," together with cellular angiofibroma and myofibroblastoma. Previous studies have shown overlapping morphologic and immunohistochemical features between these tumors and spindle cell lipoma, mammary-type myofibroblastoma, and vulvovaginal cellular angiofibroma and myofibroblastoma. In addition, typical loss of genetic material from the 13q14 region has been documented in all the above-mentioned tumors, suggesting that they are histogenetically related. We report the clinicopathologic features of 11 new cases of vulvovaginal AMFBs. Histologically, the basic common theme was a proliferation of bland-looking spindle to round-to-epithelioid cells set in an edematous to fibrous stroma, frequently arranged around thin-walled blood vessels. Two cases were composed of a prominent mature fatty component closely admixed with typical areas of AMFB, and thus, they were designated as "lipomatous AMFBs." Notably, 1 case was closely reminiscent of Sertoli cell tumor, sclerosing type, because of its predominant cord-like arrangement. Immunohistochemically, all tumors were diffusely positive for vimentin, whereas desmin and α-smooth muscle actin were expressed in a minority of cases, suggesting a fibroblastic rather than myofibroblastic differentiation. Most cases of AMFBs coexpressed Bcl-2 protein and CD99. Interestingly, all 5 cases of AMFB with evaluable signals failed to show monoallelic loss of FOXO1 loci (13q14) by fluorescence in situ hybridization. These cytogenetic findings suggest that vulvovaginal AMFB is not genetically related to cellular angiofibroma and myofibroblastoma of the lower female genital tract.

Cellular angiofibroma is a recently described histologically distinctive benign mesenchymal neoplasm composed of 2 principal components, the cellular spindle cell component and prominent stromal blood vessels. Cases in males have sometimes been called "angiomyofibroblastoma-like tumor." We describe a series of 51 cases of cellular angiofibroma to further characterize its clinicopathologic and immunohistochemical features. There were 26 women and 25 men, ranging in age from 22 to 78 years (mean 53.5, median 52 years). Men tended to be older than women. Tumor size ranged from 0.6 to 25.0 cm (overall median size 3.9 cm, median in women 2.7 cm, median in men 6.7 cm). Most common sites were the vulvovaginal region (22 cases) and the inguinoscrotal region (19 cases). Preoperative duration (known for 25 patients) ranged from 1 week to 5 years, with presentation as a painless mass, except for 1 case each with intermittent genital bleeding and a painful mass. Most lesions were located primarily in subcutaneous tissue. Most cases were grossly well marginated. Two cases showed foci of hemorrhage and 1 case showed foci of necrosis. Microscopically, 41 tumors were well circumscribed, and 2 tumors infiltrated into the surrounding tissue. All tumors consisted of bland, spindle-shaped cells, short bundles of wispy collagen and numerous small- to medium-sized thick-walled vessels. Intralesional fat（病变内脂肪） was present in 12 cases (6 female and 6 male cases). Mild cytologic atypia (5 cases/5例微小的非典型性) and frequent mitoses (3 cases/3例可见较高的核分裂) were infrequent; significant nuclear atypia and abnormal mitoses were absent. By immunohistochemistry, 29 of 48 tumors (60%) expressed CD34, 10 of 48 (21%) SMA, 4 of 48 (8%) desmin, but none expressed S-100 protein. Follow-up information was available for 40 patients (range 4-168 months; mean 31.2 months) and no patient has developed recurrence or metastasis to date.

Cellular angiofibroma with atypia or sarcomatous transformation: clinicopathologic analysis of 13 cases.(细胞性血管纤维瘤伴有非典型性或肉瘤转化：13例的临床病理分析）