Cystic Encapsulated Papillary Carcinoma in the Male Breast: An Unusual Feature With a Diagnostic Challenge

Papillary carcinoma in the male breast is uncommon. Here, we report a case of a large encapsulated papillary carcinoma (EPC) in a 62-year-old male. The patient presented with a left breast mass of 1-year duration and bloody nipple discharge for several days. Mammography and breast ultrasonography showed a large left breast mass. The initial biopsy demonstrated fat necrosis with acute and chronic inflammation only. Due to clinical suspicion, a repeat biopsy was performed and revealed scant fragments of papillary carcinoma in a background of inflammation. The patient underwent left total mastectomy. Grossly, the breast contained a 9.0 cm entirely cystic lesion lined by a hemorrhagic thick fibrotic wall. No solid area was identified in the cyst. The entire cyst wall was examined under microscopy; only a few sections with papillary carcinoma were identified. The lesion was confined to the cyst wall; so, a diagnosis of EPC was made. Compared to the previously reported EPC cases of male breast, the lesion of this case was unusually cystic, which making the diagnosis challenging. Therefore, awareness of this unusual feature, repeat biopsy when the pathology result is discordant, and extensive sampling of the lesion are essential for making the correct diagnosis and guiding patient management.