Atypical Vulvovaginal Postradiation Vascular Lesion

Cancers of the endometrium, cervix, and anus are frequently treated with radiation therapy (RT), which carries a risk for secondary malignancies. RT causes vaginal atrophy, dryness, and increased mucosal friability, predisposing to ulcers. Here, we describe "atypical vulvovaginal postradiation vascular lesion" (AVPRVL), a benign post-RT vascular lesion that histologically mimics angiosarcoma. Fifteen cases were retrospectively identified in patients aged 44 to 77 years (median: 70 y) who presented 3 to 23 years post-RT (median: 14 y), usually with vaginal bleeding. Histologically, AVPRVL demonstrated papillary endothelial hyperplasia (Masson change), mild-to-moderate nuclear atypia, and direct juxtaposition to squamous epithelium. Atypical vessels were located in fibrin and were not distributed in the native lamina propria. MYC immunohistochemistry demonstrated only scattered, weak expression in 5 tested lesions. Fluorescence in situ hybridization was negative for MYC amplification in 11 tested lesions. Five sequenced lesions lacked recurrent pathogenic alterations or copy number changes. Clinical follow-up was available for 11 patients (73%; median length: 3.3 y; range: 1 to 21.7 y). None developed metastases. Six patients (55%) experienced persistent or recurrent lesions, although sometimes it was not possible to distinguish true recurrence from new lesions developing in the RT field. At the most recent follow-up, 9 patients were alive with no evidence of disease, and 2 were alive with recurrent lesions. Ultimately, most lesions resolved with excision or cautery. Unlike RT-associated angiosarcoma, AVPRVL lacked MYC amplification, showed indolent clinical behavior, and usually resolved with conservative management. Unlike cutaneous atypical postradiation vascular proliferation, AVPRVL did not show vessels distributed within native subepithelial tissue. Instead, it more closely resembled a Masson change with nuclear atypia. We conclude that AVPRVL represents a distinctive, benign, possibly reactive vascular proliferation of the vulvovaginal mucosa occurring years after pelvic RT. The distinction between AVPRVL and angiosarcoma is critical to avoid overtreatment.