Anal phyllodes tumor in a male patient: a unique case presentation and literature review

Lesions of anogenital mammary-like glands are rare, and only 44 female cases have been reported. Herein, we describe a particularly rare case of phyllodes tumor of anogenital mammary-like glands in a 41-year-old male presenting anal bleeding. Papillectomy was performed. The excised tumor was circumscribed in shape, and after it was sliced into sections, it was noted that there were leaf-like slits on the surface of cut side. Under the microscope, the tumor was found to be biphasic, with a bland glandular epithelium and low-to-intermediate cellular stroma, which together created the leaf-like slits. Gynecomastoid hyperplasia was evident at the periphery. The epithelium showed immuno-activity for ER, PR(focal), AR, and GCDFP-15. The stromal cells showed positive staining for CD34 and vimentin. The morphology and immunophenotype were similar to benign phyllodes tumors of breast. To the best of our knowledge, this case report represents the first case of phyllodes tumor of anogenital mammary-like glands with gynecomastoid hyperplasia at the periphery in a male patient. To make a diagnosis, we had to differentiate this lesion from hidradenoma papilliferum of skin appendage, phyllodes tumor of ectopic prostatic tissue, and other tumors of anogenital mammary-like glands analogous to the breast tumor (e.g., fibroadenoma phyllodes, periductal stromal sarcoma, and spindle cell carcinoma). While gynecomastia of male breast is usually a result of hormone imbalance, our patient's tumor did not seem to be related to peripheral hormone status in the anogenital mammary-like glands. Nevertheless, because hormone imbalance has been strongly related to male breast cancer, hormone levels may need to be followed in male patients who have this rare malady.