Lymphoma as a second malignancy in a patient with neuroendocrine tumor: mimicking dedifferentiation on dual-tracer PET/CT with 68Ga-DOTANOC and 18F-FDG.

Neuroendocrine tumors (NETs) are rare tumors which express somatostatin receptors (SSTRs). We here present a case of a 50-year-old female patient with metastatic bronchial carcinoid. She underwent 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT which suggested a diagnosis of poorly differentiated NET. Biopsy of the lesion, however, revealed a second malignancy in the form of diffuse large B-cell lymphoma. Thus, very rarely, other primary tumors can mimic NETs on dual-tracer PET/CT, and biopsy is advised in doubtful cases.