Abstract:
Breast cancer is the most commonly diagnosed malignancy among women worldwide, accounting for approximately 30% of all new cancers in females annually. Risk factors include prolonged estrogen exposure (e.g., early menarche, late menopause, hormone replacement therapy), advancing age, and genetic predispositions such as BRCA1/BRCA2 mutations.
We present the case of a 51-year-old woman who initially presented with a chronic cough and was diagnosed with presumed metastatic lung adenocarcinoma in June 2024. She received chemotherapy from August to November 2024. Subsequently, she developed scalp lesions, which upon excision and pathological analysis revealed breast tissue. In January 2025, she was hospitalized for bilateral deep vein thromboses and pulmonary emboli, suggestive of a paraneoplastic hypercoagulable state. By February 2025, she developed painful oral lesions of unclear etiology—infectious, nutritional, or metastatic. Imaging revealed a right lower lobe mass with extensive metastases to the liver, lymph nodes, muscle, and bone, as well as a cardiac mass concerning for intracardiac metastasis. A liver biopsy confirmed the diagnosis of metastatic breast adenocarcinoma.
While breast cancer frequently metastasizes to bone, liver, lungs, and brain, involvement of the scalp, oral cavity, and cardiac valves is exceptionally rare. This case highlights a uniquely aggressive presentation of breast adenocarcinoma, initially misdiagnosed as a primary lung malignancy. Although scalp metastases have been sparsely documented in the literature, the combination of cutaneous, mucosal, and cardiac involvement is exceedingly uncommon.
This case underscores the importance of maintaining a broad differential diagnosis in patients with metastatic disease, especially when imaging findings are incongruent with clinical progression. It also emphasizes the value of thorough physical examination, repeated tissue sampling, and immunohistochemical analysis in identifying the true primary malignancy. Early recognition of unusual metastatic patterns can prevent diagnostic delay and facilitate timely, appropriate management.
