Adrenal ganglioneuroma with nodal metastases on 123I-MIBG SPECT/CT and 18F-FDG PET/CT.

Ganglioneuroma is a well-differentiated tumor originating from neural crest cells of the sympathetic nervous system. Although benign, a few cases have been reported that ganglioneuroma can metastasize to other sites. We report a case of adrenal ganglioneuroma with para-aortic nodal metastases with low FDG and MIBG uptake. In order to avoid unnecessary wide excision or aggressive medication, it is important to consider the possibility of ganglioneuroma preoperatively even if with metastases.

"Bloomy rind sign" in varicella-zoster virus brainstem meningoencephalitis.

The bloomy rind sign, characterized by band-like abnormalities along the surface of the brainstem on magnetic resonance imaging without contrast enhancement, has been considered a specific imaging marker for leptomeningeal metastasis from lung adenocarcinoma. In this study, we describe the case of an 85-year-old male with a 3-week history of headache, fever, and progressive cognitive impairment. The patient was diagnosed with varicella-zoster virus brainstem meningoencephalitis and magnetic resonance imaging revealed hyperintensities along the brainstem surface on fluid-attenuated inversion recovery and diffusion-weighted imaging that mimicked a bloomy rind sign. However, the patient showed no signs of lung cancer or meningeal carcinomatosis. This case suggests that the bloomy rind sign is not exclusive to leptomeningeal metastasis but can also be observed in other conditions, such as central nervous system infections.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography revealed the course of granulocyte-colony stimulating factor-associated aortitis: A case report.

A 72-year-old man with diffuse large B-cell lymphoma underwent fluorine-18 fluorodeoxyglucose (FDG) PET/CT, revealing lymphoma lesions and no evidence of aortitis. The patient received chemotherapy and was treated with granulocyte colony-stimulating factor (G-CSF) for neutropenia. During chemotherapy, the patient underwent PET/CT again, revealing FDG accumulation and wall thickening at the aortic arch, which suggested aortitis. The patient was only experiencing fatigue. G-CSF-associated aortitis was suspected, and the original G-CSF was switched to another G-CSF while continuing chemotherapy. Three months later, the third round of PET/CT showed that FDG accumulation and wall thickening of the aortic arch vanished. PET/CT may be useful for not only the diagnosis but follow-up of G-CSF-associated aortitis. Radiologists should recognize incidental aortitis on PET/CT in patients receiving G-CSF administration.

Differentiating Brown Tumor From Bone Metastasis in Parathyroid Cancer Using 18 F-FDG PET and 99m Tc-MIBI SPECT.

ABSTRACT: A 69-year-old woman presented with a right clavicle pain. CT revealed a pathological fracture of the right clavicle, multiple osteolytic lesions, and a left cervical mass. 18 F-FDG PET/CT demonstrated a marked FDG uptake in the cervical mass and osteolytic lesions indicative of metastatic parathyroid cancer. 99m Tc-MIBI SPECT/CT revealed either faint or no uptake in the osteolytic lesions. However, a histopathological analysis after a parathyroidectomy and right clavicle biopsy confirmed the diagnosis of parathyroid cancer and the presence of benign brown tumors secondary to hyperparathyroidism. Postoperative imaging showed sclerotic change and a decreased FDG uptake in the bone lesions.

Steroids May Be Associated With Extensive Skeletal Muscle Uptake of 18 F-FDG.

PURPOSE: The possibility of steroid administration inducing the extensive skeletal muscle uptake (ESMU) of FDG in PET scans was investigated. METHODS: From 8923 consecutive 18 F-FDG PET/CT scans taken at our hospital, 23 scans (15 patients) met adult age and ESMU-positive inclusion criteria. Among the 15 patients, 13 with both ESMU-positive and -negative scans were examined for association with steroid administration. RESULTS: Extensive skeletal muscle uptake was associated with a history of steroid administration ( χ2 test: P = 0.001). Notably, 20 ESMU-positive scans and 11 ESMU-negative scans were significantly different, with 0 to 95 days (median, 18.5 days) and 0 to 708 days (median, 319.0 days) since the last steroid administration, respectively (Mann-Whitney U test, P = 0.003). A significant correlation was observed between mean skeletal muscle SUV max and the number of days since the last steroid administration (Spearman rank correlation coefficient, ρ = -0.501, P = 0.004). Specifically, the degree of ESMU tended to decrease over time, after steroid administration. From multiple regression analysis, the number of days since the last steroid administration was significantly associated with mean SUV max ( P = 0.007), but the blood glucose level was not significant ( P = 0.204), revealing that the number of days since the last steroid administration was an independent risk factor. Multicollinearity was low (the variance inflation factor was 1.007 for both the number of days since the last steroid administration and blood glucose levels). CONCLUSIONS: Steroid administration within months before PET may be one cause of ESMU.

A Von Hippel-Lindau Disease-Associated Microcystic Adenoma of the Ethmoid Sinus Mimicking Metastatic Clear Cell Renal Cell Carcinoma.

ABSTRACT: A 38-year-old man with von Hippel-Lindau (VHL) disease and a history of renal cell carcinoma presented with a 2-month history of recurrent epistaxis. MRI revealed a microcystic tumor in the left ethmoid sinus with strong contrast enhancement. 18 F-FDG PET/CT showed FDG uptake (SUV max , 4.2) in the lesion. Under the suspicion of renal cell carcinoma metastasis, the patient underwent 2 surgical resections. However, based on the morphological and immunohistochemical findings, the patient was finally diagnosed with a VHL-associated microcystic adenoma of the ethmoid sinus, which is an extremely rare tumor that occurs in VHL disease.

Stepwise synaptic plasticity events drive the early phase of memory consolidation.

Memories are initially encoded in the hippocampus but subsequently consolidated to the cortex. Although synaptic plasticity is key to these processes, its precise spatiotemporal profile remains poorly understood. Using optogenetics to selectively erase long-term potentiation (LTP) within a defined temporal window, we found that distinct phases of synaptic plasticity play differential roles. The first wave acts locally in the hippocampus to confer context specificity. The second wave, during sleep on the same day, organizes these neurons into synchronously firing assemblies. Finally, LTP in the anterior cingulate cortex during sleep on the second day is required for further stabilization of the memory. This demonstrates the precise localization, timing, and characteristic contributions of the plasticity events that underlie the early phase of memory consolidation.