Case of the Season: Primary Pulmonary Collision Tumor Consisting of Carcinoid and High-Grade Spindle-Cell Sarcoma

Abstract

61-year-old man self referred to our institution for a second opinion of an incidentally detected mass on a chestradiographobtainedaspartofaroutineannualphysical examination. The patient, an asymptomatic nonsmoker, had a noncontributory medical history. Chest radiograph demonstrated a well-defined mass in the right upper lobe. Computed tomography (CT) of the chest revealed a 4.5 x3.4-cm well-circumscribed, homogeneous and smooth right upper lobemassprotrudingintotherightmainstembronchus(Fig. 1). Positron emission tomography (PET)/CT demonstrated the mass to be hypermetabolic with a standard uptake value of 17.7. A right upper lobectomy with lymph node dissection was performed via video-assisted thoracoscopic surgery. The histopathologic diagnosis was a primary collision tumor of the lung consisting of carcinoid and high-grade malignant spindle cell sarcoma, predominantly spindle cell sarcoma with a small carcinoid component (5% of the overall volume of the lesion). A peribronchial and an intralobar lymph node were positive for metastatic carcinoid. All sampled mediastinal lymph nodes were negative. The patient was clinically staged as having a T2AN1MO carcinoid and isolated sarcoma. No further therapy was recommended because the spindle cell sarcoma was localized. Only the carcinoid component, considered an indolent tumor, had metastasized to lymph nodes. Complete surgical resection was considered the treatment for the carcinoid component. Chemotherapy was not recommended because it has not been shown to significantly improve the mortality rate of a high-grade sarcoma. The patient was subsequently closely monitored with serial CTs. Approximately 1.5 years after surgery, the patient developed symptomsofdysequilibrium.Magneticresonanceimagingof the brain demonstrated a bone metastasis from the sarcoma inthetuberculumsellaandleftclivus.BrainPET/CTrevealed a hypermetabolic intrasellar lesion with a standard uptake value of 9.9 (Fig. 2). A CT of the chest demonstrated a new left upper lobe pulmonary nodule consistent with a metastasis (Fig. 3). Our diagnosis was primary pulmonary collision tumor consisting of carcinoid and high-grade spindle cell sarcoma.