99mTc(V)-DMSA and 99mTc-MDP uptake and no 67Ga-citrate uptake in a case of primary pulmonary leiomyosarcoma

Pulmonary leiomyosarcoma presenting as a pancoast tumor

A patient presenting with Pancoast syndrome was definitely diagnosed to have pulmonary leiomyosarcoma. The patient underwent a right upper lobectomy combined with resection of the chest wall, including the 1st to 3rd ribs. The disease recurred rapidly at the local and distant sites. No previous reports about pulmonary sarcoma presenting as a Pancoast tumor were found in the literature. The possibility of primary pulmonary leiomyosarcoma should be considered, and early detection and surgical resection are necessary when a round or oval tumor with necrosis is observed in the apex of the lung.

Contrast-enhanced dynamic magnetic resonance imaging of primary pulmonary leiomyosarcoma

An abnormal opacity was found incidentally on chest radiography in a 19-year-old Japanese man with lumbago. Chest computed tomography (CT) revealed a 55 x 40 mm well-defined mass with smooth margins in the lower lobe of the right lung (S6). Contrast-enhanced dynamic CT showed that the lesion was not enhanced, suggesting a cystic lesion, such as a bronchogenic cyst. However, contrast-enhanced dynamic magnetic resonance imaging (MRI) revealed enhancement of the lesion, which had a clear margin and homogenous consistency, suggesting a benign pulmonary solid tumor. Video-assisted thoracoscopic surgery, S6 segmentectomy, was performed, disclosing the lesion to be solid. Histopathologically, the tumor consists of spindle cells with ample eosinophilic cytoplasm arranged in an interlacing pattern. Immunohistochemical staining revealed positive desmin reactivity but was negative for alpha smooth muscle actin and HHF-35 (muscle specific actin), indicating atypical phenotypic differentiation. The lesion was accordingly diagnosed as leiomyosarcoma with low grade malignancy, and right lower lobectomy was performed. The patient has remained free from recurrence for 18 months without any additional chemotherapy or radiation therapy. Contrast-enhanced dynamic MRI should be carried out to facilitate accurate preoperative diagnosis and selection of the correct surgical plan.