Primary Large Cell Neuroendocrine Carcinoma: A Cause of Extracardiac Uptake Site of Tc99m Tetrofosmin Tamer Atasever, GLilin Vural, Klvdclm Ayla, and Can Oztfirk T C-99M TETROFOSMIN, like TC99m ses- tamibi is a lipophilic cationic myocardial imaging agent. This agent also has been used in the detection of various tumors. A case of extracardiac Tc99m tetrofosmin uptake is presented in this report. CASE REPORT A 37-year-old man was admitted with a 1-month history of cough, dyspnea, sputum, and chest pain. Chest radiography showed bilateral parahilar en- largement (Fig 1). Thorax computed tomography (CT) demonstrated heteregenous lobulated mass measured 13 • 8 cm in the anterior mediastinum adjacent to the main vascular structures. TC-99m Tetrofosmin myocard perfusion scan was performed before mediastinoscopy and pear- shaped increased activity accumulation was seen above the heart (Fig 2). Mediastinoscopic biopsy was performed and histopathology revealed pri- mary large cell neuroendocrine carcinoma. The patient was referred for chemotherapy. Sites of Extracardiac TC99m Tetrofosmin Uptake: COMMON AND UNCOMMON 1. Breast carcinoma 1,2,3 2. Benign breast diseases a. Fibroadenoma 4,5 b. Fibrocystic disease4 c. Mastitis3 3. Lymph node metastases 1 4. Lymph node uptake (nonspecific) 6 5. Lung carcinoma (squamous, adeno, small cell Ca)7,8 6. Lung metastases9,1~ 7. Benign lung diseases a. Pneumonia 7 b. Tbc 7 c. Bronchiolitis obliterans7 8. Malign pleural mesotheliomaH 9. Thyroid cancers a. Differentiated thyroid cancers ]~ b. Medullary thyroid Ca 14 Fig 1. Chest radiography shows bilateral parahilar enlarge- ment suggesting mediastinal mass. 10. Benign thyroid diseases a. Thyroid adenomas 15-17 b. Thyroiditis17 11. Parathyroid 1s,19 12. Bone and soft tissue turnouts 2~ 13. Bone metastases ]2,21-23 14. Brain tumors (primary and metastatic)24,25 15. Hypopharyngeal carcinoma9 16. Esophageal carcinoma9 17. Maxillary carcinoma9 18. Primary large cell neuroendocrine carcinoma From the Gazi University Faculty of Medicine, Departments of Nuclear Medicine and Pulmonary Diseases, Ankara, Turkey. Address reprint requests to Tamer Atasever, MD, Rafet Canitez Caddesi Akin 1Apt. 2/25, Oran (06450), Ankara, Turkey. Copyright 9 1998 by W.B. Saunders Company 0001-2998/98/2802-000958.00/0 Fig 2. Tc99m Tetrofosmin scintigraphy shows pear-shaped activity accumulation above the heart, 196 Seminars in Nuclear Medicine, Vol XXVlII, No 2 (April), 1998: pp 196-197