Unicentric Castleman’s Disease Revealed by 18F-FDG PET/CT and Somatostatin Receptor Scintigraphy With 99mTc-HYNIC-TOC

A Rare Case of Follicular Dendritic Cell Tumor of the Abdominal Cavity Visualized by 18 F-AlF-NOTA-Octreotide PET/CT

ABSTRACT

Positivity of follicular dendritic cell tumor in somatostatin receptor imaging is rare. A 68-year-old woman underwent ultrasound in health examination. The results showed abnormal echoes in the pancreatic head region, suggestive of a neuroendocrine tumor of the pancreatic head. 18 F-AlF-NOTA-octreotide PET/CT was performed for staging. 18 F-AlF-NOTA-octreotide PET/CT revealed an irregular mass between the caudate lobe of the liver and the pancreatic head with heterogeneously increased uptake, which was later confirmed as follicular dendritic cell tumor by pathological examination.

Hypermetabolic Unicentric Castleman Disease of Kidney on FDG PET/CT

ABSTRACT

A 62-year-old man presented with a huge lesion of left kidney on ultrasound in a health examination 1 month ago. The mass showed hypervascularity on enhanced CT and intense FDG uptake on FDG PET/CT in the lower pole of kidney, which suggested renal malignancy. The histopathological result after surgical resection of the mass confirmed the diagnosis of Castleman disease, the hyaline vascular variant.

A 10-year observational single-center study of retroperitoneal unicentric Castleman disease

Diagnosis of unicentric Castleman disease (UCD) is not easy before the resection and obtainment of pathological result. We retrospectively summarized 10-year experience of clinical evaluation and management for retroperitoneal UCD in Peking Union Medical College Hospital (PUMCH) between December 1, 2009 and December 31, 2019. Seventy two UCD patients with pathological diagnosis after resection were screened out. Among them 25 patients had retroperitoneal UCD. The average age of the 25 patients was 43.80 ± 12.79, and 52.00% were male. No patients had systemic symptoms, and 1 patient got preoperative treatment. The average size of masses was 5.59 ± 2.86 cm. The UCD sites included kidney, adrenal area, perinephric area, pancreas, peripancreatic area, area of descending part of duodenum, periaortic area or beside iliac artery, and others. The masses presented different degree of enhancement on CT scans and hypoecho or isoecho on ultrasound. Increased metabolism could be found on 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT). Some patients had positive results on somatostatin receptor imaging, but none had positive results on 131I-metaiiodo-benzylguanidine (131I-MIBG). Some patients presented the elevated level of interleukin-6 (IL-6), 24hour-urinary catecholamine and tumor markers. All the patients received complete resection of masses and 96.00% had hyaline-vascular type pathology except 1 patient (plasma cell-type). Ninety two percent patients received a long-term follow-up with an average follow-up time of 35.48 ± 33.90 months. No patients died or experienced relapse during follow-up. Differential diagnosis of retroperitoneal UCD may be difficult according to imaging and laboratorial examinations. Differential diagnosis with pheochromocytomas/paragangliomas should be taken into special consideration. Different imaging examinations, such as CT/MRI, 18F-PET/CT, somatostatin receptor imaging and 131I-MIBG, can be combined for differential analysis. Complete resection is the best treatment and could provide a final pathological diagnosis.

Adrenal Castleman Disease on 99mTc-HYNIC-TOC Scan and FDG PET/CT

Adrenal Castleman disease is very rare. We reported image findings of a right adrenal mass in a 75-year-old man on Tc-HYNIC-TOC scan and FDG PET/CT. There was obviously elevated Tc-HYNIC-TOC activity, but the intensity of FDG activity was remarkable. Pheochromocytoma was initially suspected. However, pathology from resected specimen showed adrenal Castleman disease.

The value of multiparameter 18F-FDG PET/CT imaging in differentiating retroperitoneal paragangliomas from unicentric Castleman disease

The aim of this study was to investigate the value of multiple parameters retrieved from the FDG PET/CT studies, including SUVmax, SUVmean, SUVpeak, MTV, TLG, tumour size in differentiating retroperitoneal paragangliomas from UCD. 28 patients with solitary retroperitoneal masses who had undergone preoperative 18F-FDG PET/CT were retrospectively evaluated. Histopathology by surgical resection confirmed 17 paragangliomas and 11 UCDs. SUVmax, SUVmean, SUVpeak, MTV, TLG, and tumour size of 18F-FDG PET/CT were measured for each patient. Mann-Whitney U-test was used to assess differences in multiple parameters between paragangliomas and UCDs. The ROC curve analysis was performed to determine the differential diagnostic value of these parameters. Paragangliomas presented significantly higher SUVmax (P < 0.001), SUVmean (P = 0.001), SUVpeak (P < 0.001), and TLG (P = 0.024) than UCDs, whereas no significant difference was observed in MTV. The AUCs for differentiating paragangliomas and UCDs were 0.920, 0.888, 0.909, and 0.765 for SUVmax, SUVmean, SUVpeak, and TLG, respectively. The SUVmax cut-off of 7.75 yielded 82.4% sensitivity and 100% specificity for predicting paragangliomas. This study indicated that 18F FDG PET/CT-derived multiple metabolic parameters are useful in distinguishing between paragangliomas and UCDs. SUVmax showed the best result for the differential diagnosis of these two diseases among multiple metabolic parameters.

99mTc-Labeled Native RBC Scintigraphy in Distinguishing Polysplenia From Abdominal Masses in a Patient With Situs Inversus Totalis

A 39-year-old previously healthy woman presented possible hematuria. An ultrasound examination showed right adrenal mass and suggested pheochromocytoma. A Tc-HYNIC-TOC SPECT/CT was performed, which incidentally detected situs inversus totalis and suspicion of polysplenia without definite normal spleen in the right upper abdomen. In order to differentiate the polysplenia from other etiologies, a heat-damaged Tc RBC scintigraphy was performed. The images showed significant activity in the multiple soft tissue nodules in the posterior right abdomen, consistent with ectopic polysplenia.