Inflammatory myofibroblastic tumor masquerading as carcinoma.

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm that can closely mimic malignancy on imaging, particularly in the lung where spiculated, fluorodeoxyglucose-avid nodules frequently raise suspicion for non-small cell lung cancer (NSCLC). Because of its overlapping radiographic features and variable molecular alterations, IMT often requires surgical resection for definitive diagnosis and treatment. We report a 54-year-old man with a spiculated, PET-avid left upper lobe pulmonary nodule incidentally discovered on surveillance imaging. He was asymptomatic, with no smoking history but a family history of lung cancer. Percutaneous biopsy was nondiagnostic, prompting robotic-assisted wedge resection with lymph node dissection. Gross examination revealed a 10 mm well-circumscribed lesion, and histopathologic analysis demonstrated spindle-shaped myofibroblastic cells within a lymphoplasmacytic background. Immunohistochemistry was positive for ALK-1, desmin, actin, myosin, and STAT6, confirming IMT. Surgical margins and all mediastinal and hilar lymph nodes were negative for malignancy. The patient's postoperative course was uncomplicated, and he was discharged the following day with no residual symptoms. This case underscores the diagnostic challenge of IMT, which can radiographically and clinically resemble primary lung carcinoma. When noninvasive evaluation is inconclusive, surgical excision provides both diagnosis and cure. Clinicians should consider IMT in the differential diagnosis of solitary pulmonary nodules, particularly in nonsmokers, and incorporate molecular testing to guide management and avoid unnecessary aggressive interventions.