Cellular angiofibroma of the vulva: a clinicopathological study of two cases with documentation of some unusual features and review of the literature.

Abstract

Cellular angiofibroma (CA) of the vulva is a recently described condition, whose clinical and pathological features are poorly known. We have encountered two cases of this very unusual tumor. Their clinical and pathological features were analyzed and compared to those reported in the literature. Both patients were middle-aged women. In each case, the lesion had the clinical appearance of a vulvar cyst, located in the lateral aspect of the clitoris and the right labium majus, respectively. Microscopically, the lesions were well circumscribed but not truly encapsulated. Both were composed of small spindle cells arranged in short fascicles and mixed up with relatively abundant small- or medium-sized rounded vessels. While mitotic activity was perceptible in both cases, no cellular atypia could be demonstrated. A striking feature seen in one case was the presence of pseudoangiomatous changes in the stroma, similar to those occasionally found in spindle cell lipoma. Phenotypically, the tumor cells consistently expressed vimentin, CD99, and both estrogen and progesterone receptors. A discrete CD34 or smooth muscle actin immunoreactivity was also found in one case. No expression of S-100 protein, Bcl-2 protein, CD117 (c-kit gene product), epithelial membrane antigen, desmin, or h-caldesmon could be demonstrated. This study further illustrates that CA of the vulva has distinct clinical and pathologic features that set it apart from the other soft tissue conditions involving this area. However, like many soft tissue neoplasms, this tumor also exhibits some variation in its histological or immunohistochemical features.