Subcutaneous Soft Tissue Metastases in Lung Adenocarcinoma: A Surprising Initial Presentation on Bone Scintigraphy

Initial disease presentations are often surprising compared with expected clinical trajectories. We present a case of metastatic lung adenocarcinoma where the initial presentation was masquerading as a musculoskeletal soft tissue mass. Initial concern was for a hematoma after light trauma, but due to a pacemaker, MRI was contraindicated. Workup included a 99mTc-MDP bone scan where the lesion demonstrated activity. Further workup imaging was serendipitous, revealing a left upper lobe mass. Biopsy demonstrated poorly differentiated adenocarcinoma of lung origin. Soft tissue metastasis can occur with lung adenocarcinoma, and although it constitutes a less frequent metastatic route, it is nevertheless clinically important.