The vulva is heavily involved by well to moderately differentiated neoplastic glands. Note the arrow pointing to squamous epithelium of the vulva.
Typical neoplastic colonic glands with dark columnar nuclei.
The neoplastic glands are immunopositive for CK20, as expected.
Metastatic tumors to the vulvovaginal region may arise from Mullerian organs (ie. endometrial, ovarian and tubal carcinomas as well as carcinosarcomas) or from epithelia of distant organs such as breast, bladder, kidney, melanomas and colorectum.
This is an interesting case of a patient with history of colorectal carcinoma who presented with a mass in the vulva. Immunohistochemical studies (CK7 negative, CK20 positive) supported the histologic features of colorectal carcinoma.