Abstract
BACKGROUND: Primary adenocarcinomas of the vulva, particularly those from anogenital mammary-like glands, are exceedingly rare. These typically encompass a spectrum of cancers, including ductal, lobular, mixed ductal-lobular, tubular, and mucinous types, predominantly with invasive growth patterns. CASE DESCRIPTION: A 73-year-old woman reported an 8-year history of a slowly enlarging vulvar mass, the mass skin surface color of the tumor was normal and there was no ulceration, redness, heat and pain, no skin itching and abnormal secretions. Examination revealed a 3 cm cyst-like nodule on the left vulva. Surgical excision was performed. Pathology showed a 2.5 cm nodular mass with a soft, mucinous texture. Microscopic analysis revealed a uniform cell distribution with papillary and solid patterns. Immunohistochemical staining showed estrogen receptor (ER), progesterone receptor (PR), epithelial membrane antigen (EMA), pan-cytokeratin [CK(pan)], GATA-binding protein 3 (GATA3) expression, among others, with a Ki67 index around 10%, suggesting a specific tumor profile-encapsulated papillary carcinoma, originating from the vulva anogenital mammary-like glands. CONCLUSIONS: This article presents a unique case of anogenital mammary-like gland adenocarcinoma-encapsulated papillary carcinoma. It closely mirrors the morphology, immunohistochemistry, and biological behavior of its breast counterpart. Due to its slow progression and localized, encapsulated nature, the treatment approach for this carcinoma differs from other vulvar adenocarcinomas, aligning more with carcinoma in situ management similar to breast encapsulated papillary carcinoma.