MUC5AC and mesonephric adenocarcinoma: Mesonephric adenocarcinoma, one of the rarest tumors of the female genital tract, is defined by the World Health Organization (WHO) as a tumor with tubular glands lined by mucin-free cuboidal epithelium, luminal eosinophilic hyaline secretions with solid papillary, ductal or retiform architectural arrangements deriving from remnants of mesonephric (Wolffian) ducts.5These ducts run along the Mullerian ducts.