Pulmonary large cell neuroendocrine carcinoma (LCNEC) with confirmed liver metastases negative on (18)F-FDG and (68)Ga-DOTATATE PET

Lung neuroendocrine neoplasms (NENs) encompass the low-, intermediate-, and high-grade entities. Differentiated NENs overexpress somatostatin receptors, which are targeted by (68)Ga-DOTA-conjugated peptides in molecular imaging with positron emission tomography. Less differentiated NENs may have lost their expression of somatostatin receptors and thus show lower uptake of (68)Ga-DOTA-peptides; however, these tumors express GLUT-1 and can be imaged with (18)F-fluordeoxyglucose (FDG). We report the case of a 72-year-old patient with a poorly differentiated, high grade lung NEN, which was (18)F-FDG-positive at initial diagnosis. After treatment and remission, the patient had histologically confirmed relapse in the liver. Interestingly, these hepatic metastases did not demonstrated radiopharmaceutical uptake at neither (18)F-FDG nor (68)Ga-DOTATATE positron emission tomography/computed tomography.