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131I scan plays a crucial role in the management of patients with differentiated thyroid cancer for the evaluation of remnant thyroid tissue, residual/recurrent metastatic disease, posttherapy tracer distribution, and response assessment to high-dose 131I therapy. Different causes secondary to physiological, pathological, and anatomical variations have been described for false-positive findings in the whole-body planar images. This case report of a patient of differentiated thyroid cancer with undocumented trauma to the left knee region a day before receiving the high-dose radioiodine therapy showed an interesting image finding of tracer uptake at unusual site in the posttherapy whole-body 131I scan.

Xanthogranulomatous inflammation in the spinal epidural space is extremely rare. We report a case of a 62-year-old man with a xanthogranulomatous inflammation in the spinal epidural space mistaken for lymphoma because of its avid F FDG uptake on PET/CT. This case emphasizes the need for caution when evaluating a spinal epidural mass using F FDG PET/CT as xanthogranulomatous inflammation can induce a false-positive reading on F-FDG PET/CT.

Kimura disease is a chronic inflammatory disorder that occurs mainly in Asians. We present a patient with pulmonary Kimura disease assessed by whole-body 18F-FDG PET/CT examination and proved by pathologic findings. Chest x-ray detected left pulmonary hilum enlargement in a 49-year-old Chinese man. CT showed a soft tissue mass with punctate calcifications in the left pulmonary hilum, which obviously and homogeneously accumulated tracer on FDG PET. Histopathology findings showed characteristic of Kimura disease. Kimura disease should be included in the differential diagnosis of a pulmonary hilar tumor.

PET/CT is a widely accepted imaging modality in the diagnosis and staging of lymphoma because of the increased FDG uptake commonly detected in malignant lesions. However, various causes of false-positive FDG localization have been described, including in nonmalignant lymph nodes. We report a patient with a history of Hodgkin lymphoma who presented with bilateral axillary lymphadenopathy, which was intensely FDG-avid on PET/CT imaging. Biopsy of lymph nodes from both axillae revealed benign follicular hyperplasia. Follicular hyperplasia is a potential false-positive finding on PET/CT imaging, and obtaining pathologic confirmation of malignancy should be considered before treatment.

Somatostatin receptor scintigraphy with In-111 octreotide has shown excellent accuracy in many neuroendocrine tumors, including carcinoid. Substantial gallbladder activity may be present on early images; however, the administration of a fatty meal and/or the effect of time generally results in littl