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Abstract: A 61-year-old man presented with papillary thyroid cancer in radioiodine-refractory status after high-activity 131 I treatments following thyroidectomy. FDG-avid neck and pulmonary metastases but without 131 I-uptake were detected. CCDC6-RET fusion was identified from the tumor lesion. He was treated with pralsetinib, a RET inhibitor, followed by another high-activity 131 I therapy. Posttherapeutic scan displayed restoration of 131 I avidity at those lesions only shown on previous FDG PET/CT. Reduced FDG avidity of those lesions and decreased serum antithyroglobulin antibody titer were also noticed. This case illustrated successfully reinduced 131 I avidity in papillary thyroid cancer through redifferentiation with target therapy to suppress tumor RET overexpression., Competing Interests: Conflicts of interest and sources of funding: The authors declare that they have no conflicts of interest. This work was supported in part by the following research grants: KSVGH21-CT12-19 from Kaohsiung Veterans General Hospital, Taiwan and VAC111-004 from Veterans Affairs Council, Taiwan., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: We presented here a 71-year-old man with a history of thyroid cancer post total thyroidectomy and 131I ablation and right renal cell carcinoma post right partial nephrectomy. He reported persistent chest tightness and pain after the first dose of the Moderna COVID-19 (mRNA-1273) vaccine. Thus, coronary heart disease was suspected, and the patient was referred for MPI (myocardial perfusion imaging). Focal 201Tl uptake in the left axillary region was found incidentally on MPI, and SPECT/CT revealed enlarged benign-looking lymph nodes. The diagnostic is in favor of reactive hyperplasia after the intramuscular injection of vaccine into left deltoid muscle., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

A 77-year-old man with lung cancer underwent fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). Cervical FDG uptake of variable intensity was detected corresponding to enlarged masses in the bilateral parotid and left submandibular regions. We suspected metastases from primary lung cancer or coexisting salivary gland neoplasms. Histopathological examination of the FDG-avid parotid mass revealed Mikulicz disease, an uncommon autoimmune disease involving the salivary glands. We present this case of Mikulicz disease with "quasi-symmetric" FDG avidity in the major salivary glands. We believe that salivary FDG uptake can lead to erroneous interpretation of tumor staging using PET.

A female patient aged 75 years presented with an incidental pulmonary nodule without FDG uptake when undergoing FDG PET/CT. Without obtaining histologic diagnosis, the follow-up FDG PET/CT 2 years later demonstrated intense FDG avidity within previously FDG-negative tumor. After surgery, the pathologic diagnosis is pulmonary lymphoepithelioma-like carcinoma (LELC). LELCs are unique because of histologic similarities with undifferentiated nasopharyngeal lymphoepithelioma and with a better prognosis as compared with other lung malignancies. However, the expression of FDG uptake in LELC has never been discussed. Herein, we describe a pulmonary LELC manifesting as a slowly growing tumor displaying conversion from FDG-negative to -positive avidity.

A 61-year-old uremic male under hemodialysis underwent Tc-99m sestamibi scintigraphy due to suspicious secondary hyperparathyroidism. The images showed increased uptake in the right forearm, left shoulder, right knee and, to a lesser extent, in the left hip and the right thigh. Subsequent Tc-99m MDP bone scintigraphy and x-ray studies revealed intense extraosseous uptake and calcified masses in areas corresponding to those found in Tc-99m sestamibi scintigraphy, suggesting tumoral calcinoses. We demonstrate the rare case in which Tc-99m sestamibi was taken up by tumoral calcinoses.

A 76-year-old man with previous sigmoid colon resection for adenocarcinoma had low back pain for 2 months. Whole-body bone scintigraphy showed multiple focal Tc-99m methylene diphosphonate (MDP)-avid lesions in both rib cages and 3 lumbar vertebrae, indicating metastases. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging was performed for further evaluation of this possible metastatic disease and demonstrated the lumbar and costal metastases and several hypermetabolic areas in the pelvic bones, multiple thoracic vertebrae, both shoulders, and the right femur. Histopathologic examination of the right-sided iliac crest, however, revealed multiple myeloma.