Uncovering an uncommon diagnosis: Encapsulated papillary carcinoma of the male breast in a Jordanian patient-A case report.

Male breast cancer is rare. Encapsulated Papillary Carcinoma (EPC) is an uncommon, low-grade subtype that presents as a solitary cystic tumor. EPC comprises 2%-3% of male breast cancers and is difficult to diagnose due to challenges in biopsy and its similarity to benign lesions. We present a case of EPC in an middle-aged male with complicated preoperative imaging findings. A 58-year-old male presented with a stable, non-painful left breast mass noticed six years ago. Initially diagnosed as a lipoma, the ultrasound revealed a suspicious BIRADS 4 mass. CT imaging showed a mass with small lymph nodes. An intraoperative frozen section raised suspicion of malignancy, and the diagnosis of EPC was confirmed on definitive paraffin-section histopathology. The patient underwent surgery, and histopathology revealed positive hormone receptors and negative surgical margins. Postoperative recovery was uneventful except for a minor hematoma. EPC is an uncommon breast cancer subtype that arises from the cystic wall, with a low recurrence rate after surgery. Diagnosis is challenging due to low atypia and difficulty obtaining biopsy samples. EPC, often hormone receptor-positive, is typically treated with surgical resection, and mastectomy may be needed depending on tumor location. After complete excision with clear margins, pure EPC is managed analogously to ductal carcinoma in situ and does not routinely require systemic adjuvant therapy; endocrine therapy is considered on an individualized basis, and adjuvant treatment is otherwise guided by any invasive component. EPC is an uncommon and diagnostically challenging malignancy with a favorable prognosis when confined to the cyst wall. Complete surgical excision with clear margins is the primary treatment; for pure EPC, no systemic adjuvant therapy is routinely required, and endocrine therapy is considered on an individualized basis. With management aligned to current guidelines, EPC generally results in favorable outcomes.