18F-FDG PET/CT imaging features of patients with multicentric Castleman disease

A variant of KSHV-associated inflammatory cytokine syndrome in elderly men of Mediterranean descent

The spectrum of HHV-8-associated disorders includes Kaposi's sarcoma, primary effusion lymphoma, multicentric Castleman's disease, and the recently described KSHV inflammatory cytokine syndrome (KICS), a life-threatening disorder complicating HIV infection. There have been no reports in the literature concerning non-immunosuppressed individuals affected with KICS. We report here a KICS-like illness occurring in two elderly Greek men without HIV infection or other recognizable cause of immunosuppression.

Overview of F18-FDG uptake patterns in retroperitoneal pathologies: imaging findings, pitfalls, and artifacts

INTRODUCTION

Retroperitoneum can be the origin of a wide variety of pathologic conditions and potential space for disease spread to other compartments of the abdomen and pelvis. Computed tomography (CT) and magnetic resonance imaging (MRI) are often the initial imaging modalities to evaluate the retroperitoneal pathologies, however given the intrinsic limitations, F18-FDG PET/CT provides additional valuable metabolic information which can change the patient management and clinical outcomes. We highlight the features of retroperitoneal pathologies on F18-FDG PET/CT and the commonly encountered imaging artifacts and pitfalls. The aim of this review is to characterize primary and secondary retroperitoneal pathologies based on their metabolic features, and correlate PET findings with anatomic imaging.

CONCLUSION

Retroperitoneal pathologies can be complex, ranging from oncologic to a spectrum of non-oncologic disorders. While crosse-sectional imaging (CT and MRI) are often the initial imaging modalities to localize and characterize pathologies, metabolic information provided by F18-FDG PET/CT can change the management and clinical outcome in many cases.

Case report: detection of multiple sporadic gastrointestinal stromal tumors by dual-time 18 F-FDG PET/CT

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors affecting the gastrointestinal tract. Typically, GISTs are solitary; however, in rare cases, they may be multiple and appear in one or more organs. Multiple GISTs can appear in familial GISTs, children, or certain tumor syndromes such as neurofibromatosis type 1, Carney syndrome, and Carney-Stratakis syndrome. However, the diagnosis of primary multiple sporadic GISTs is often more difficult than that of these diseases. Herein, we report a case of multiple primary sporadic GISTs in a 64-year-old man, affecting the abdominal cavity and retroperitoneum, as identified through dual-time point positron emission tomography (PET) with 18F-labeled fluoro-2-deoxyglucose (18F-FDG) and computed tomography (18F-FDG PET/CT). Notably, the dual-time-point PET/CT revealed the migration of masses near the lower abdomen into the abdominal cavity. Furthermore, a significant increase in radioactive uptake of the mass 3 h after 18F-FDG injection compared with that 1 h after injection may be an important cue for its diagnosis.

Imaging of Castleman Disease

Castleman disease (CD) is a group of rare and complex lymphoproliferative disorders that can manifest in two general forms: unicentric CD (UCD) and multicentric CD (MCD). These two forms differ in clinical manifestation, imaging appearances, treatment options, and prognosis. UCD typically manifests as a solitary enlarging mass that is discovered incidentally or after development of compression-type symptoms. MCD usually manifests acutely with systemic symptoms including fever and weight loss. As a whole, CD involves lymph nodes throughout the chest, neck, abdomen, pelvis, and axilla and can have a wide variety of imaging appearances. Most commonly, lymph nodes or masses in UCD occur in the chest, classically with well-defined borders, hyperenhancement, and possible characteristic patterns of calcification and/or feeding vessels. Lymph nodes affected by MCD, while also hyperenhancing, tend to involve multiple nodal chains and manifest alongside anasarca or hepatosplenomegaly. The polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) subtype of MCD may demonstrate lytic or sclerotic osseous lesions in addition to features typical of MCD. Since a diagnosis of CD based solely on imaging findings is often not possible, pathologic confirmation with core needle biopsy and/or surgical excision is necessary. Nevertheless, imaging plays a crucial role in supporting the diagnosis of CD, guiding appropriate regions for biopsy, and excluding other potential causes or mimics of disease. CT is frequently the initial imaging technique used in evaluating potential CD. MRI and PET play important roles in thoroughly evaluating the disease and determining its extent, especially the MCD form. Complete surgical excision is typically curative for UCD. MCD usually requires systemic therapy. ^©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Unmet Clinical Needs in the Management of Idiopathic Multicentric Castleman Disease: A Consensus-based Position Paper From an ad hoc Expert Panel

Castleman disease describes a group of heterogeneous clinicopathological disorders now included in the tumor-like lesions with B-cell predominance of the World Health Organization classification. Managing idiopathic multicentric Castleman disease (iMCD) is challenging, because few systematic studies or comparative randomized clinical trials have been conducted. International, consensus evidence-based guidelines for iMCD were published in 2018, but gaps in the therapeutic options for difficult-to-treat patients, who do not respond to siltuximab and other conventional therapies, still exist. This article presents the results of group discussion among an ad hoc constituted Panel of Italian experts to identify and address unmet clinical needs (UCNs) in managing iMCD. Recommendations on the appropriateness of clinical decisions and proposals for new research concerning the identified UCNs were issued through formalized multiple-step procedures after a comprehensive analysis of the scientific literature. The following key UCNs were addressed: strengthening the diagnostic certainty in iMCD patients before planning first-line therapy; management of siltuximab therapy; choice and management of immune-modulating, or chemotherapy agents in patients resistant/intolerant to siltuximab therapy. While most of the conclusions reached by the Panel are consistent with the existing guidelines, some alternative therapeutic options were stressed, and the discussion contributed to bringing forth the issues that need further investigation. Hopefully, this comprehensive overview will improve the practice of iMCD and inform the design and implementation of new studies in the field.

18F-FDG PET/CT and contrast-enhanced CT in the diagnosis of Castleman disease

OBJECTIVE

Castleman disease (CD) is a rare group of lymphoproliferative disorders, which is easily confused with lymphoma or other solid tumors. Hence, this study aimed to investigate the diagnostic role of ¹⁸F-FDG PET/CT and contrast-enhanced CT (CECT) in patients with CD.

METHODS

Clinicopathological characteristics, and ¹⁸F-FDG PET/CT and CECT findings and parameters were retrospectively reviewed in 32 patients with CD.

RESULTS

These 32 patients (12 males, 20 females; median age, 41 years) consisted of 17 unicentric CD (UCD) patients and 15 multicentric CD (MCD) patients. Compared with MCD, UCD had a higher prevalence in female (82.4% vs. 40.0%) and hyaline vascular subtype (94.1% vs. 40.0%) (P < 0.05). FDG uptake was avid in all cases, including moderate uptake in 7 cases and intense uptake in 25 cases. The median SUVmax, SUVmean, MLV, and TLG of all cases were 4.4 (range, 1.4-23.6), 2.7 (range, 1.1-15.2), 26.6 (range, 4.8-393.0), and 78.8 (range, 9.4-1545.6), respectively. The lesions of 29 cases showed homogeneous enhancement, and marked enhancement was observed in 27 cases. ¹⁸F-FDG PET/CT corrected 6.3% CECT diagnoses, while CECT corrected 37.5% PET/CT diagnosis. The accuracy of combined PET/CT and CECT was superior to PET/CT or CECT alone (78.1%, 31.3%, and 62.5%). Besides, higher SUVmax and SUVmean were found in male subjects, MCD, and plasma cell subtype (P < 0.05), while higher MLV and TLG were observed in larger lesion size and volume (P < 0.05).

CONCLUSION

Castleman disease most commonly appears as marked and homogeneous enhancement meanwhile with moderate or intense FDG uptake. ¹⁸F-FDG PET/CT combined with CECT was the effectively diagnostic modality for CD. The glucose metabolism of CD was associated with gender, clinical classification, histopathological classification, and lesion size and volume.

Case Report: A rare case of primary hepatic Castleman’s disease mimicking a liver tumor

Castleman’s disease (CD) is a primary lymphoproliferative disorder of the lymph nodes with rare extra-nodal primary affection. Solid organ involvement is rare, and isolated liver involvement is extremely rare. Here we presented a case of a 59-year-old woman with a hepatic lesion accidentally found by ultrasound. The MRI result indicated primary liver malignancy or liver metastases. ¹⁸F-FDG PET/CT could not exclude hepatic malignant tumor due to its high metabolism. Finally, the hepatic CD was confirmed by postoperative pathology.