A Breast Mass That Was Not Breast Cancer: Chest Wall-Invading Non-small Cell Lung Carcinoma Presenting as a Retroareolar Tumor in a Male Patient.

A painful retroareolar mass in a male patient may initially suggest a primary breast process, but in rare cases it may reflect contiguous spread from an intrathoracic malignancy. Distinguishing between these possibilities is essential because delayed recognition may affect staging, resectability, and treatment planning. We present the case of a 50-year-old man with a history of tobacco use who presented with a progressively enlarging and painful right retroareolar mass. Physical examination revealed a firm, fixed, tender subareolar lesion measuring approximately 5 cm. CT of the chest demonstrated a heterogeneous soft tissue mass involving the right anterior chest wall, with extension through the intercostal space and intrathoracic involvement. Surgical exploration revealed a tumor extending through the chest wall deep to the pectoralis major muscle, with contiguous growth into the subareolar region. Debulking and biopsy were performed. Frozen section analysis was suspicious for squamous cell carcinoma, and final histopathologic evaluation demonstrated non-small cell lung carcinoma (NSCLC) with immunophenotypic features of hepatoid differentiation. The lesion was deemed unresectable because of extensive local invasion into surrounding structures. A permanent venous access port was placed, and the patient was referred for systemic platinum-based chemotherapy with immunotherapy after multidisciplinary staging and oncology evaluation. This case highlights a rare clinical presentation of lung malignancy manifesting as a retroareolar mass in a male patient and emphasizes the importance of maintaining a broad differential diagnosis when evaluating fixed, painful chest wall and breast-region lesions.