Benign müllerian glandular inclusions in men undergoing pelvic lymph node dissection

Benign müllerian-type glandular inclusions in lymph nodes are commonly seen in women, but to our knowledge, there have only been 4 reported cases in men. Distinction of these glandular structures from metastatic adenocarcinoma is crucial for proper staging, prognosis, and treatment of the patient. We report 3 cases of benign müllerian-type glandular inclusions in men undergoing either prostatectomy or cystoprostatectomy with lymph node dissection for treatment of prostatic adenocarcinoma and/or urothelial carcinoma. None of the patients were receiving hormonal therapy. All 3 cases showed benign glands with ciliated cuboidal to columnar cells and rare secretory cells, morphologically comparable with endosalpingiosis in women. These glands were diffusely positive for PAX-8, WT-1, estrogen receptor, and progesteron receptor consistent with müllerian origin. Our study is the first to confirm müllerian origin of these glands by PAX-8 and WT-1 positivity. This finding of müllerian glands in men identical to endosalpingiosis in women supports the theory that this entity can result from müllerian metaplasia of the peritoneal mesothelium rather than displacement of tubal-type epithelium. Pathologists should also be aware that müllerian-type glands can rarely occur in men to prevent the incorrect diagnosis of metastatic adenocarcinoma involving a lymph node.