A Rare Case of Spindle Cell Carcinoma of the Lung

Background: Spindle cell carcinoma (SCC) of the lung is a rare, poorly differentiated variant of non–small-cell lung cancer (NSCLC) with aggressive behavior and limited therapeutic options. Case Presentation: We report a 78-year-old man with a history of rectal cancer who presented with back pain, altered mental status, dyspnea, and chest pain. Laboratory findings revealed hypercalcemia of malignancy with metabolic encephalopathy and prerenal acute kidney injury. Imaging demonstrated a 7.6 × 5.1-cm right upper-lobe pulmonary mass with metastases to bone, liver, and adrenal gland. Endobronchial ultrasound showed >90% obstruction of the right upper-lobe bronchus. Transbronchial biopsy confirmed spindle cell carcinoma, positive for keratin AE1/AE3 and negative for HMB45 and CD45. Next-generation sequencing identified a MET exon 14 skipping mutation. The patient received palliative spine radiation and capmatinib 300 mg twice daily, with improvement of hypercalcemia after intravenous fluids and zoledronic acid. Given advanced disease, poor functional status, and clinical decline, care was transitioned to hospice. Conclusion: This case highlights the aggressive course of pulmonary SCC and the significance of identifying targetable alterations such as MET exon 14 skipping.