• Computed tomography
• Magnetic resonance imaging
• Mesenchymal
• Neoplasms
• Spleen
• Stroma

• Humans
• Diagnosis, Differential
• Magnetic Resonance Imaging/methods
• Splenic Neoplasms/diagnostic imaging
• Splenic Neoplasms/pathology
• Tomography, X-Ray Computed/methods
• Stromal Cells/pathology

• Case report
• Follicular dendritic cell sarcoma
• Spleen
• Surgery

• comprehensive treatment
• follicular dendritic cell sarcoma
• pathological diagnosis
• schizophrenia
• systematic review
• tonsil

• case report
• follicular dendritic cell
• hepatic
• inflammatory pseudotumor
• sarcoma

• Nantong Science and Technology Bureau
• Nantong Municipal Commission of Health and Family Planning

• EBV-positive inflammatory follicular dendritic cell sarcoma
• Histiocytic sarcoma
• Inflammatory pseudotumor
• Mesothelial cyst
• Sclerosing angiomatoid nodular transformation
• Spleen

• Humans
• Male
• Female
• Dendritic Cell Sarcoma, Follicular/pathology
• Herpesvirus 4, Human/genetics
• Epstein-Barr Virus Infections/complications
• Epstein-Barr Virus Infections/diagnosis
• Retrospective Studies
• Soft Tissue Neoplasms
• Hemangioma

• Clinicopathological features
• Epstein–Barr virus-associated tumor
• Follicular dendritic cell sarcoma
• Inflammatory pseudotumor variant
• Laparoscopic surgery
• Molecular mechanisms

Inflammatory pseudotumor (IPT)-like follicular dendritic cell sarcoma (FDCS) is a rare neoplasm referred to as the FDCS variant. Here we report a 66-year-old female patient suffering from hepatic IPT-like FDCS and summarize IPT-like FDCS reported in the literature. The patient presented with obvious abdominal pain without significant laboratory abnormalities and subsequently underwent surgical resection of a hepatic lesion. Postoperative pathological results demonstrated a vascular tissue-rich neoplasm (7.0-cm maximum diameter). The tumor cells expressed CD21 and CD35, and in situ hybridization detected Epstein–Barr virus-encoded RNA (EBER). Metastasis or recurrence was not detected during the 7-year follow-up.

• National Natural Science Foundation of China

• B cells
• FDCs
• dendritic cells
• immunity
• sarcoma

• diagnosis
• follicular dendritic cell sarcoma
• mutations
• personalized medicine

Inflammatory pseudotumor-like follicular dendritic cell sarcoma is a rare histological variant of follicular dendritic cell sarcoma involving typically the spleen and the liver, often linked to the presence of Epstein–Barr virus infection. Definite diagnosis of this type of sarcoma is difficult to make owing to nonspecific clinical and imaging findings and is based on histopathological features. Inflammatory pseudotumor-like follicular dendritic cell sarcoma is described as a low-aggressivity tumor with a favorable prognosis.

We report the case of a 34-year-old Caucasian woman, Epstein–Barr virus positive, diagnosed with hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma and surgically treated in November 2014, who developed 6 years later a recurrence for which she underwent once again surgical treatment. As far as we know, fewer than 30 reports of inflammatory pseudotumor-like follicular dendritic cell liver tumors have been reported in the English literature.

Although it is an uncommon tumor, inflammatory pseudotumor-like sarcoma is a diagnostic worth being taken in consideration, and surveillance is recommended owing to the possibility of recurrence.

• Case report
• Epstein–Barr virus
• Follicular dendritic cell sarcoma
• Hepatic tumor
• Inflammatory pseudotumor

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare tumor. This study aimed to reveal the radiological characteristics of IPT-like FDCS by radiologic-pathologic correlation.

We analyzed two cases of IPT-like FDCS in the liver, nine in the spleen, and two in both the liver and spleen concomitantly. IPT-like FDCS presented as well-defined iso- or hypodense masses on unenhanced computed tomography (CT) images in both the liver and spleen. Hyperintensities on T1-weighted images and hypointensities on T2-weighted images with hypointense rings were characteristic features in splenic cases. “Halo signs” were observed in two out of three liver tumors. Hepatic lesions showed significant enhancement, whereas splenic lesions showed only mild enhancement. Delayed annular enhancement was observed in both liver and spleen cases. On ultrasonographic examination, IPT-like FDCS presented as hypoechoic lesions with enhancement similar to that observed on CT. Hyaline fibrous pseudocapsules, which correlated with the hypointensities on T2-weighted images, were microscopically observed at the tumor edge. IPT-like FDCS was characterized by an abundance of small blood vessels and capillaries. Capillaries were also found in the fibrous capsule of some IPT-like FDCSs, which may explain the delayed annular enhancement.

The manifestations of IPT-like FDCS in the liver and spleen showed differences that warrant them to be approached differently during diagnosis. Characteristic radiological findings of IPT-like FDCS included different enhancement patterns between liver and spleen tumors and rim-like hypointensities on T2-weighted images, as well as annular enhancement on CT and magnetic resonance images. These imaging features correlated with tumor pathology.

• Computed tomography
• Histopathology
• Inflammatory pseudotumor-like follicular dendritic cell sarcoma
• Magnetic resonance imaging
• Ultrasonography

Inflammatory pseudotumor (IPT)-like follicular dendritic cell (FDC) sarcoma is rare. The 2017 World Health Organization classification of tumors of hematopoietic and lymphoid tissues noted that data on its clinical outcome are limited, but that the tumor appears to be indolent. The aim of this study was to summarize the clinical characteristics, treatment outcomes, and prognostic factors for IPT-like FDC sarcoma. A literature review was conducted on retrospective analyses of clinical data and prognostic information on IPT-like FDC sarcoma reported between 2001 and 2020. A total of 67 cases of IPT-like FDC sarcoma were retrieved from the literature, documenting that it occurs predominantly in middle-aged adults, with a marked female predilection. Six patients had a separate malignancy and five had an autoimmune disease. Typically involving the spleen and/or liver, it may also selectively involve the abdomen, gastrointes-tinal tract, pancreas, retroperitoneum, and mesentery. Necrosis, hemorrhage, noncaseating epithelioid granulomas, and fibrinoid deposits in blood vessel walls are often present. The neoplastic cells are predominantly positive for follicular dendritic cell markers such as cluster of differentiation 21 (CD21), CD23, CD35 and CNA.42 and are consistently Epstein-Barr virus (EBV)-positive. Mitoses were very rare in most cases. Most patients were treated by surgery alone. Disease status at the time of last follow-up was known for 57 patients with follow-up time ranging from 2 to 144 mo. Local and/or distant recurrence after initial treatment was seen in 15.8% of the patients. The 1- and 5-year progression-free survival for the entire group was 91.5% and 56.1%, respectively. Kaplan-Meier and multivariate analyses showed that age, sex, tumor size, and pathological features were not risk factors for disease progression. IPT-like FDC sarcoma appears to be mildly aggressive and requires annual surveillance. Surgery is the most effective treatment modality, and the role of adjuvant chemotherapy for postoperative management is unclear. EBV is likely to play an important role in the etiology of IPT-like FDC sarcoma.

• Inflammatory pseudotumor-like
• Follicular dendritic cell sarcoma
• Spleen
• Liver
• Prognosis
• Epstein-Barr virus

• EBV
• colonic
• follicular dendritic cell sarcoma
• inflammatory

• Extramedullary hematopoiesis
• Histiocytic
• Mastocytosis
• Myeloid
• Myeloproliferative neoplasm
• Spleen

Follicular dendritic cell (FDC) sarcoma/tumor is a rare malignant tumor of follicular dendritic cells, which is considered a low-grade sarcoma that can involve lymph nodes or extranodal sites. Conventional FDC sarcomas are negative for Epstein-Barr virus (EBV), whereas the inflammatory pseudotumor-like variant consistently shows EBV in the neoplastic cells.

We report two cases of inflammatory pseudotumor-like FDC sarcoma in the liver that received 3D laparoscopic right hepatectomy and open right hepatectomy separately.

EBV probe-based in situ hybridization and detection of immunohistochemical markers of FDC play an important role in the diagnosis and differential diagnosis of inflammatory pseudotumor-like FDC sarcoma. Complete surgical excision combined with regional lymphadenectomy may be effective in reducing the postoperative recurrence and metastasis and improving long-term survival rates.

• Inflammatory pseudotumor-like follicular dendritic cell sarcoma
• Epstein-Barr virus
• Liver
• Spleen
• Case report

Inflammatory pseudotumor-like follicular dendritic cell (IPT-like FDC) tumors of the liver is an uncommon tumor with extremely low incidence. To date, the radiologic findings of this tumor in multiphase computed tomography (CT) and magnetic resonance imaging (MRI) imaging have not been described.

Patient 1 is a 31-year-old Chinese female, whose complaining incidentally coincided with the finding of multiple liver masses. In the local hospital, an abdominal enhanced CT found two hypo-dense solid lesions, with heterogeneous sustained hypoenhancement, in the upper segment of the liver’s right posterior lobe. In our hospital, enhanced magnetic resonance imaging (MRI) with hepatocyte-specific contrast agents showed a similar enhanced pattern of lesions with patchy hyperintensity in the hepatobiliary phase (HBP). The patient underwent surgery and recovered well. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found on the regular re-examination. Patient 2 is a 48-year-old Chinese male admitted to our hospital for a huge unexpected hepatic lesion. A dynamic enhanced abdominal CT revealed a huge heterogeneous enhanced solid tumor in the right lobe of the liver with a size of 100 mm × 80 mm, which showed a heterogeneous sustained hypoenhancement. In addition, enlarged lymph nodes were found in the hilum of the liver. This patient underwent a hepatic lobectomy and lymph node dissection. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found upon regular re-examination.

When a hepatic tumor shows heterogeneous sustained hypoenhancement with a patchy enhancement during HBP, an IPT-like FDC tumor should be considered in the differential diagnosis.

• Magnetic resonance imaging
• Computed tomography
• Inflammatory pseudotumor-like follicular dendritic cell tumor
• Liver

• Adult
• China
• Dendritic Cells/metabolism
• Diagnosis, Differential
• Female
• Hepatectomy
• Hepatitis B, Chronic/complications
• Humans
• Incidence
• Inflammation
• Liver/diagnostic imaging
• Liver Neoplasms/diagnostic imaging
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Postoperative Period
• Respiratory Tract Infections/complications
• Respiratory Tract Infections/diagnostic imaging
• Tomography, X-Ray Computed

• Disseminated juvenile xanthogranuloma
• Erdheim-Chester disease
• Follicular dendritic cell sarcoma
• Histiocytic sarcoma
• Indeterminate dendritic cell tumor
• Interdigitating dendritic cell sarcoma
• Langerhans cell histiocytosis

• Anaplastic carcinoma
• Constitutional symptoms
• Follicular dendritic cell tumor
• Inflammatory myofibroblastic tumor
• Inflammatory pseudotumor
• Paraneoplastic syndromes
• Rhabdoid
• SWI/SNF
• Undifferentiated

Mediastinal follicular dendritic cell sarcoma (FDCS) is extremely rare. Due to potential under-recognization of this disease, it happens to be misdiagnosed, especially on core needle biopsy. We report 3 cases of mediastinal FDCS and provide a literature review to improve better understanding of the tumor and to reduce misdiagnosis.

Three cases of mediastinal FDCS in our clinic practice were studied, including their core needle biopsy and resected specimens, and those cases reported previously in English literature were retrieved and analyzed.

The core needle biopsy of case 1 showed a tumor reminiscent of classical Hodgkin’s lymphoma (CHL), while the resected mass was finally diagnosed with FDCS combined with hyaline-vascular Castleman’s disease. Both the biopsy and resected tissue of case 2 were constitutive of the clear epithelioid cells with marked atypia. In both cases, definitive diagnoses were not made on core needle biopsy. In case 3, there were some areas morphologically similar to CHL, and some areas contained ovoid to spindle-shaped tumor cells with fascicular pattern. The analysis of 43 cases of mediastinal FDCS showed the age of patients were from 16 to 76 years old, the male to female ratio was 1.5:1, the maximal tumor diameters were 3–17 cm. 18 cases were underwent preoperative biopsy, whereas 15 (83.3%) of which were misdiagnosed initially, often as lymphoma. 32 patients had available follow-up data, the rates of recurrence, metastasis, and mortality were 12.5, 18.8 and 28.1%, respectively. Current limited data suggested no statistical differences between adverse prognosis and gender, age, tumor size, necrosis, or different therapeutics, respectively.

Mediastinal FDCS is a rare malignancy that has yet not been fully understood and been often misdiagnosed, particularly when making a diagnosis on core needle biopsy. Increased awareness of this enigmatic tumor is crucial to avoid diagnostic pitfalls.

• Follicular dendritic cell sarcoma
• Mediastinum
• Pathological diagnosis
• Prognosis
• Radiology

• Anaplastic lymphoma kinase
• Familial adenomatous polyposis
• Gastric fundic gland polyposis
• Inflammatory myofibroblastic tumors

• cytology
• fine needle aspiration
• inflammatory pseudotumor-like follicular dendritic cell sarcoma
• spleen