Paget's disease of the male breast: a case report.

The patient was a 91-year-old man with change in nipple appearance, itching and redness, and a palpable breast mass. At presentation, mammary Paget’s disease (PD) was clinically suspected. Skin biopsy was performed and showed epidermis invaded by Paget cells, characterized by hyperchromatic nuclei and abundant pale-staining cytoplasm. Computed tomography and mammary ultrasonography confirmed the absence of an underlying invasive carcinoma, and the patient underwent right mastectomy and sentinel lymph node biopsy (SLNB). Both sentinel lymph nodes were found to be negative perioperatively, and further axillary dissection was not performed. Pathological results revealed no malignancy under the nipple, yet the Paget cells were more widely spread than expected. The patient was followed up without the need of postoperative chemotherapy. Male mammary PD is an extremely rare breast cancer, and there is no standard preoperative assessment or operative procedure. Mammography is many times unable to detect possible underlying breast carcinoma in female patients with mammary PD, and previous studies have reported that the detection rate was less than 50 %. However, some researchers reported that magnetic resonance imaging (MRI) might be more detectable to confirm the extent of the cancer. The extent of the skin change around the nipple is often different from the actual perimeter of Paget cells. In extra-mammary PD, mapping biopsy is known to be useful to determine areas free of cancer. The benefits of SLNB have also been demonstrated for the management of less invasive breast cancers, and previous reports have shown that the use of SLNB is reasonable for treatment of mammary PD without underlying invasive cancer. MRI, mapping biopsy, and SLNB are all less invasive procedures and thus may be suitable for treatment of male mammary PD.