-
Erickson Finnegan posted an update 6 months, 1 week ago
Pembrolizumab was ceased, and a repeat FDG PET/CT scan showed regression of uptake in the thyroid gland and colon, in keeping with resolution of inflammatory change. Immune-related adverse events induced by Immune checkpoint inhibitors, such as pembrolizumab, should be recognized-cessation of treatment often leads to resolution.We report the case of a 57-year-old man who presented with a 6-year history of yellowish plaques on his left buttock and right medial knee, as well as ulcerating subcutaneous nodules on his forearms bilaterally. Skin biopsy, bone biopsy, and serum protein electrophoresis confirmed the diagnosis of necrobiotic xanthogranuloma with associated monoclonal gammopathy. Necrobiotic xanthogranuloma is a rare form of non-Langerhans histiocytosis characterized by development of chronic cutaneous nodules that enlarge over time to form plaques. Navitoclax The author discusses necrobiotic xanthogranuloma’s presentation and the utility of F-FDG PET/CT in disease staging, localizing optimal biopsy sites, and assessing treatment response.A patient with multiple episodes of gastrointestinal bleeding underwent Tc-labeled red blood cell scintigraphy to detect the source of bleeding, which showed a focally increased activity in the upper midabdomen. SPECT/CT demonstrated that the activity was located in the pancreatic head. Angiography confirmed the diagnosis of pancreatic arteriovenous malformation. After transarterial embolization therapy, the patient no longer had bleeding episode. Based on the present case, pancreatic arteriovenous malformation should be included as differential diagnosis during Tc-red blood cell scintigraphy.Ga-prostate-specific membrane antigen (PSMA) PET/CT for primary staging of high-risk prostate cancer revealed increased Ga-PSMA uptake in a known periappendicular abscess in a patient, who had undergone surgical drainage of the abscess 1 month earlier. The case presents another example of Ga-PSMA uptake in a benign infectious and inflammatory condition.F-FDG is the most widely used PET tracer worldwide. Before the examination, recommendations are given to patients to avoid muscular activities, with the goal to limit F-FDG uptake in muscles. Here, we report the case of a 36-year-old man with Hodgkin disease referred to our department to perform an F-FDG PET/CT for immunotherapy assessment. The PET images showed a homogeneous, symmetric, and very intense uptake of the masticatory muscles. The medical examination exhibited a trismus, and the patient revealed to have been using cocaine 15 minutes before injection of F-FDG.Extrapulmonary tuberculosis (TB) is difficult to diagnose. Here, we report a case of extrapulmonary TB in a 68-year-old woman presented with mental fatigue, poor appetite, and weight loss. F-FDG PET/CT revealed elevated F-FDG uptake in the left inferior cervical, left supraclavicular, mediastinal, and splenic hilum lymph nodes and spleen, which were suspected of malignant tumor. To further differentiate benign and malignant diseases, Ga-FAPI PET/CT was performed. Ga-FAPI PET/CT also showed intense Ga-FAPI uptake in the previously mentioned FDG-avid lesions. However, biopsy of the left supraclavicular lymph node demonstrated the presence of TB.A 61-year-old woman diagnosed with left breast cancer underwent a bone scan for the evaluation of possible bone metastases. Multiple foci of elevated activity were noticed in the spine and pelvis. In addition, a focus of intense activity was observed in the right lung on the SPECT/CT images without corresponding anatomic abnormality.A 35-year-old woman with rectal neuroendocrine tumor, Ki-67 proliferation index less than 2%, and a mediastinal mass on CT postoperatively was referred for restaging with PET/CT Ga-DOTATATE. The examination showed uptake on the pelvic lymph node and mediastinal mass. Because of differences in lesions’ SUVs and clinical presentation, the hypothesis of lymphoma for the mediastinal mass was raised, and F-FDG PET/CT was performed, which showed glycolytic hypermetabolism in the mediastinal mass and absence of hypermetabolism in pelvic lymph nodes. Transthoracic biopsy of the mass revealed atypical large-cell lymphoid proliferation, and immunohistochemistry study was compatible with Castleman disease.Malignant peripheral nerve sheath tumor (MPNST) originates from Schwann cells or pluripotent perineural cells, which is an extremely rare tumor that occurs in the kidney. We report a case of MPNST in transplanted kidney that was diagnosed in a 32-year-old man with a history of kidney transplantation. Contrast-enhanced MRI and F-FDG PET/CT features of MPNST are described, which can accurately discriminate MPNST from infection and benign tumors. These features could potentially provide valuable information to distinguish it from other renal malignancies. F-FDG PET/CT may be a useful tool for the primary diagnosis and the initial staging of MPNST.A 68-year-old man with sarcoidosis showed high F-FDG uptake in the mediastinal and hilar lymph nodes on F-FDG PET, suggesting active inflammation. F-fluoro-boronophenylalanine (FBPA) PET showed no significant uptake in the mediastinal and hilar lymph nodes, suggesting its cancer specificity as a substrate of L-type amino acid transporter 1. F-fluoro-boronophenylalanine PET can be used for precise evaluation in oncology when the differentiation between inflammation and metastasis is inconclusive on F-FDG PET.Pleural and pericardiac effusion could have radioiodine accumulation and be potential pitfall on posttherapeutic I whole-body scintigraphy. However, the volume of the effusion was relatively massive in the previous publications. We report a case of pleural effusion with a very small volume also had radioiodine uptake in a 37-year-old man.Recent PET/CT systems permit short acquisition with acceptable image quality. In addition, continuous-bed-motion mode is available for whole-body PET imaging with some PET cameras providing better uniformity and reproducibility throughout the field of view. We demonstrate a case with patient motion during the dynamic scan. Although the total summation of serial whole-body scan showed image artifact, the first 15 minutes’ summation of the serial scans provided high-quality images by eliminating the frames with motion. This acquisition mode seems to be particularly useful to perform for those who may likely to move during PET scan.