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Splenic biopsies for cytology remain challenging due to the inherent difficulty in obtaining adequate samples and the paucity of literature on rare entities arising in the spleen. Among these, are tumors arising from blood vessels, lymphomas and rarely, mesenchymal dendritic cell neoplasms. An important but rarely considered entity primarily arising in the spleen is Epstein-Barr virus-positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS). EBV+ IFDCS is an indolent neoplasm with useful cytomorphologic and distinct biologic characteristics that can be evaluated on fine-needle aspiration (FNA) cytology and small biopsies. In this report, we present a challenging case with the final diagnosis facilitated by cytomorphology and diagnostic markers in an ambiguous initial presentation., (© 2024 Wiley Periodicals LLC.)

Objective: The present study aims to explore the clinicopathological characteristics of Epstein-Barr virus (EBV)-positive inflammatory follicular dendritic cell sarcoma (IFDCS; EBV+ IFDCS)., Case Report: The case involved a 32-year-old woman who underwent surgical resection of a splenic nodule. Histological examination and immunohistochemistry were performed using cluster of differentiation (CD) markers, and in-situ hybridization was conducted to detect EBV-encoded RNA (EBER)., Results: A microscopic analysis revealed neoplastic cells with various morphologies, including round, ovoid, or spindled shapes, dispersed within a prominent lymphoplasmacytic infiltrate. The tumor cells exhibited nuclear atypia, with some resembling Reed-Sternberg cells. The immunohistochemistry demonstrated focal positivity for follicular dendritic cell markers, such as CD21, CD23 and CD35, and focal negativity for other markers, including CD3, CD34, CD20, CD79a, myeloperoxidase and HMB45. Additionally, the EBER staining showed strongly positive results. The patient showed no local recurrence or metastasis during the 13-month follow-up., Conclusion: A comprehensive understanding of EBV+IFDCS, including its clinicopathological features and immunohistochemical characteristics, is crucial for accurate diagnosis and differential diagnosis of this rare tumor., (© 2024 by the Association of Clinical Scientists, Inc.)

Background: Spleen Epstein-Barr Virus (EBV)-positive inflammatory follicular dendritic cell sarcoma (FDCS) is rare, and the imaging signs are unclear. The COVID-19 has been confirmed to be the cause of pneumonia and can cause a variety of diseases including myocarditis. However, it has not been reported to be the cause of the exacerbation or activation of EBV-positive inflammatory FDCS., Objective: The objective is to extract the imaging features of EBV-positive inflammatory FDCS in the spleen and analyze the reasons for the special features of this case., Methods: By analyzing the patient's treatment process and imaging examinations (A 77-year-old female was admitted to the hospital due to generalized discomfort and pain symptoms. When she was admitted to the hospital a year earlier with COVID-19 pneumonia, a chest CT scan showed that she had a splenic tumor. During this admission, CT scans showed two irregularly shaped and unevenly dense soft tissue density masses within the spleen, with uneven enhancement on contrast-enhanced im-aging within the solid components and along the edges. PET/CT scans revealed elevated glucose metabolism in the masses. Postoperative pathological diagnosis confirmed splenic EBV-positive inflammatory FDCS.), reading the literature, sorting out the disease cognitive process, epidemiology, and pathological data of EBV-positive inflammatory FDCS, we discussed the imaging manifestations and possible differential diagnosis of the disease., Results: The patient was finally diagnosed with splenic EBV-positive inflammatory FDCS., Conclusions: Imaging features of EBV-positive inflammatory FDCS in the spleen include a high incidence of hemorrhage and necrosis, persistent moderate enhancement of the solid portion, a "capsular-like enhancement" structure at the tumor edge, and possibly active glucose metabolism with high Standardized Uptake Values (SUVs). COVID-19 infection and long-term COVID-19 sequelae may exacerbate and activate EBV-positive inflammatory FDCS in the spleen, and the mechanism remains to be further studied.

Inflammatory pseudotumor-like follicular/fibroblastic dendritic cell sarcoma (IPT-like FFDCS) is a rare, indolent neoplasm that occurs in the spleen or liver and harbors Epstein-Barr virus (EBV) integrated into the host genome. The molecular genetic characteristics of IPT-like FFDCS have not been well studied and there are no established and actionable molecular features to guide treatment decisions or diagnosis beyond the recognition of viral genome integration. We subjected two cases of IPT-like FFDCS to a comprehensive next-generation sequencing analysis. Several variants of uncertain clinical significance were detected in both tumors. No variants of potential or strong clinical significance were detected within the targeted regions of the evaluated genes. Additionally, no fusion events were detected involving the genes in either tumor. The performed molecular analysis identified no genetic aberrations in IPT-like FFDCS and its genomic landscape remains, with the exception of a monoclonal EBV gene, largely undefined.

Inflammatory pseudotumor (IPT)-like follicular dendritic cell (FDC) sarcoma is a recently described rare tumor and considered a unique entity, with different histologic appearances and behavior from those of the classical FDC sarcoma. This study analyzed the clinical and pathological findings of two such cases that the authors encountered and 36 previously reported cases identified in the literature. Assessment of all 38 cases showed a slight female predominance (2.2:1) with a median age of 56.5 years. Seventeen patients complained of abdominal discomfort or pain, while fifteen patients had no clinical symptom. Almost all cases occurred in liver (n=20) or spleen (n=17). Except in one case, all patients underwent surgical resection of the tumor alone. Histologic features showed a mixture of chronic inflammatory cells and variable amounts of spindle cells with vesicular nuclei and distinct nucleoli. The tumor cells expressed conventional FDC markers such as CD21 (75%), CD35 (92%), CD23 (62%), clusterin (75%), and CNA.42 (100%). EBV was detected in thirty-five cases (92.1%) by Epstein-Barr virus (EBV)-encoded RNA in situ hybridization, and EBV-latent membrane protein-1 was expressed in 90% of the cases. With a median follow-up of 21 months, 29 patients (85.3%) were alive and well, 4 (11.8%) were alive with disease, one patient (2.9%) died of disease. Only four patients with hepatic tumors underwent recurrence or metastasis after initial treatment. Epstein-Barr virus is thought to play a role in the development of the tumor; however, the pathogenesis of the disease and the origin of tumor cells remain unclear.

Inflammatory pseudotumor (IPT)-like follicular dendritic cell (FDC) sarcoma is a rare neoplasm typically occurring in the spleen or liver. We present six cases of EBV(+) IPT-like FDC sarcoma of the spleen among Koreans along with their clinicopathologic features and IHC results. Most patients presented with an asymptomatic, incidentally detected single splenic mass and were successfully managed by splenectomy alone. Concomitant disease was found in one case, showing EBV(+) gastric carcinoma with lymphoid-rich stroma. Histologic features showed fibro-inflammatory lesions that were often accompanied by necrosis and epithelioid histiocytic collection, which are barely distinguishable from IPT. Tumor cells did not frequently express conventional FDC markers, including CD21 (3/6 positive cases), clusterin (4/6), and D2-40 (2/6), but showed uniform positivity for smooth muscle actin (SMA). Noticeably, significant numbers of IgG4(+) plasma cells were found within all six tumors. We suggest that the diagnosis of IPT-like FDC sarcoma should be made by the application of a panel of FDC markers, and CD21 negativity or SMA positivity cannot be the criterion for exclusion of IPT-like FDC sarcoma. Relationship of IPT-like FDC sarcoma of the spleen and IgG4-related sclerosing disease should be investigated in further studies., (© 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Various splenic inflammatory pseudotumours are reported to be infected with Epstein-Barr virus (EBV), which is thought to be associated with the pathogenesis of the lesion. The term "inflammatory pseudotumour (IPT)-like follicular dendritic cell tumour", all cases of which are also EBV positive, has recently been proposed. Here, we describe the imaging findings of these splenic tumours and present the cases of an IPT-like follicular dendritic cell tumour and two EBV-positive inflammatory pseudotumours in two female patients and one male patient. These splenic lesions were found incidentally on pre-operative or post-operative screening or at medical check-up. CT performed on all three patients revealed low-density solitary masses in the spleen. MRI was performed on one patient; the solitary mass demonstrated isointensity on T(1) weighted images and low intensity on T(2) weighted images relative to the surrounding splenic parenchyma. Dynamic MRI study revealed that the mass did not enhance on the early phase but enhanced to the same degree as the surrounding splenic parenchyma on the delayed phase. The imaging findings are almost identical to those found in conventional IPT because the morphology is similar in both cases; however, attention should be paid to this new entity in the diagnosis of splenic lesions because of its neoplastic nature. Longer follow-up is also necessary for these patients compared with those with conventional IPT.