Primary Vaginal Adenocarcinoma with Intestinal Differentiation: Diagnostic Complexity and Individualised Radiation Planning

Abstract

Primary vaginal cancer is a rare entity, accounting for 1% - 2% of gynaecological malignancies, with squamous cell carcinoma and adenocarcinoma comprising 80% - 85% and < 10% of cases, respectively. Adenocarcinoma is generally a clear cell histology, with intestinal differentiation being an exceptionally rare neoplasm, representing one of the least common histological variants of vaginal cancer. Owing to its morphological and immunophenotypic resemblance to metastatic colorectal adenocarcinoma, establishing a diagnosis requires meticulous clinicopathological correlation and exclusion of a gastrointestinal primary. Given its rarity, evidence regarding the optimal management of vaginal adenocarcinoma remains inconclusive. We present a case highlighting the diagnostic complexity using immunohistochemistry, clinicopathological features, and multidisciplinary management, including chemotherapy and radiation, which required individualised planning in the setting of treatment-limiting toxicity.