Morphological and Immunohistochemical Features of Angiomyofibroblastoma: A Case Report with Review of the Literature

Abstract

Angiomyofibroblastoma is a rare tumor seen predominantly in women of childbearing age.  Here we report a case of angiomyofibroblastoma with unusual immunohistochemical features in a 62-year-old woman.  The patient presented with a 9.5 cm mass in her left labium for one year.  Microscopic examination of surgically resected specimen showed a well-circumscribed mass with alternating paucicellular and hypercellular areas in the background of an edematous and collagenous stroma with vascular proliferation.  Tumor cells showed high nuclear/cytoplasmic ratio, oval nuclei with finely granular chromatin, inconspicuous nucleoli and a few mitoses (3/per 10 High Power Fields).  Immunohistochemically, these cells were positive for vimentin, estrogen receptors and progesterone receptors, and negative for CD34, S-100, HMB45, BerEp4, cytokeratins, synaptophysin and E-cadherin.  The above immunohistochemical findings helped us to rule out melanoma, adenocarcinoma, neuroendocrine tumors and metastases from the breast origin.  Considering the overall morphological features of the tumor, it was diagnostic of angiomyofibroblastoma.  Although a literature review shows that angiomyofibroblastomas are generally diffusely positive for desmin and focally positive for α-smooth muscle actin (SMA) with only very rare exceptions, desmin and SMA immunostains were negative in our case.  We like to emphasize that it is important to be aware of the potential variations in the immunophenotypes of angiomyofibroblastomas in order to make a correct diagnosis.