Cytological features of inflammatory pseudotumor-like follicular dendritic cell sarcoma of spleen: A case report

Cytomorphology of follicular dendritic cell sarcoma: a report of 7 cases with an emphasis on the diagnostic challenges

BACKGROUND

Follicular dendritic cell sarcoma is a malignant neoplasm derived from germinal center follicular dendritic cells, which both share a characteristic immunophenotype (namely CD21, CD23, and CD35). Cytomorphologic descriptions are few, consisting of only 26 prior cases from 24 publications. Identification by cytologic means appears challenging as the majority of previous reports disclose an erroneous or indeterminate initial cytologic diagnosis. Herein, we present the largest cytology series to date with the aim of expanding upon this small body of literature and discuss possible factors resulting in misinterpretation.

MATERIALS AND METHODS

A retrospective search was conducted from 2 academic medical centers to identify histologically confirmed cases of follicular dendritic cells with an associated cytologic component. Clinicopathologic data were tabulated and a comparative analysis of cytomorphologic and immunohistochemical features was performed.

RESULTS

Seven separate cases were identified. All cases showed cohesive tumor cells with a characteristic voluminous, ill-defined cytoplasm with interconnecting fibrillary processes and intimately admixed mature lymphocytes. Features were maintained across various cytologic preparations, including conventional smear, liquid-based cytology, and touch imprint. Unusual immunohistochemical profiles were noted in a subset of cases.

CONCLUSIONS

Cytomorphology is highly conserved across cases and preparations; however, a propensity for aberrant immunoexpression may contribute to diagnostic errors. Cytomorphologic features, supported by immunohistochemistry, suggest fine-needle aspiration as a reasonable diagnostic modality. Tumors with these features should include CD21, CD23, and/or CD35 in the workup.

Surgical treatment of liver inflammatory pseudotumor-like follicular dendritic cell sarcoma: A case report

BACKGROUND

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is rare with a low malignant potential. Hepatic IPT-like FDCS has similar clinical features to hepatocellular carcinoma (HCC), making it extremely difficult to distinguish between them in clinical practice. We describe the case of a young female patient diagnosed with HCC before surgery, which was pathologically diagnosed as IPT-like FDCS after the left half of the liver was resected. During 6 mo of follow-up, the patient recovered well with no signs of recurrence or metastasis.

CASE SUMMARY

A 23-year-old female patient with a 2-year history of hepatitis B presented to the Affiliated Hospital of Guizhou Medical University. She was asymptomatic at presentation, and the findings from routine laboratory examinations were normal except for slightly elevated alpha-fetoprotein levels. However, ultrasonography revealed a 3-cm diameter mass in the left hepatic lobe, and abdominal contrast-enhanced computed tomography revealed that the tumor had asymmetrical enhancement during the arterial phase, which declined during the portal venous phase, and had a pseudo-capsule appearance. Based on the findings from clinical assessments and imaging, the patient was diagnosed with HCC, for which she was hospitalized and had undergone laparoscopic left hepatectomy. However, the tumor specimens submitted for pathological analyses revealed IPT-like FDCS. After surgical removal of the tumor, the patient recovered. In addition, the patient continued to recover well during 6 mo of follow-up.

CONCLUSION

Hepatic IPT-like FDCS is difficult to distinguish from HCC. Hepatectomy may provide beneficial outcomes in non-metastatic hepatic IPT-like FDCS.

Case report: Hepatic inflammatory pseudotumor-like follicular dendritic cell sarcoma: A rare case and minireview of the literature

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.

Imaging and pathological comparison of inflammatory pseudotumor-like follicular dendritic cell sarcoma of the spleen: A case report and literature review

Background

Inflammatory pseudotumor-like follicular dendritic cell sarcoma (IPT-like FDCS) is a rare subtype of follicular dendritic cell sarcoma (FDCS) that is mainly located in the liver and spleen (1). Splenic IPT-like FDCS is a rare low-grade malignancy with non-specific clinical manifestations and laboratory findings. Herein, we reported the pathological and imaging features of a case with splenic IPT-like FDCS.

Case presentation

A 57-year-old woman was found to have a mass in the spleen during a physical examination and was hospitalized for further treatment. Her laboratory results were within the normal range. Unenhanced and contrast-enhanced computed tomography scans of the whole abdomen showed a round mass in the spleen, with a diameter of about 5 cm. After further examination with enhanced MRI, a provisional diagnosis of splenic hemangioma or splenic hamartoma was made. The patient underwent splenectomy, and the pathological diagnosis was splenic IPT-like FDCS. No tumor recurrence or metastasis was found during the 1-year follow-up after the operation.

Conclusions

Herein, we reported a case of splenic IPT-like FDCS. Although the clinical examination and laboratory examination lack specificity, the imaging of this case showed that the lesion was a solid mass with progressive enhancement, and the central scar showed the characteristics of delayed enhancement, which facilitated the diagnosis.

Follicular dendritic cells

Follicular dendritic cells (FDCs) are unique accessory immune cells that contribute to the regulation of humoral immunity. They are multitasker cells essential for the organization and maintenance of the lymphoid architecture, induction of germinal center reaction, production of B memory cells, and protection from autoimmune disorders. They perform their activities through both antigen-driven and chemical signaling to B cells. FDCs play a crucial role in the physiological regulation of the immune response. Dis-regulation of this immune response results when FDCs retain antigens for years. This provides a constant antigenic stimulation for B cells resulting in the development of immune disorders. Antigen trapped on FDCs is resistant to therapeutic intervention causing chronicity and recurrences. Beyond their physiological immunoregulatory functions, FDCs are involved in the pathogenesis of several immune-related disorders including HIV/AIDS, prion diseases, chronic inflammatory, and autoimmune disorders. FDCs have also been recently implicated in rare neoplasms of lymphoid and hematopoietic tissues. Understanding FDC biology is essential for better control of humoral immunity and opens the gate for therapeutic management of FDC-mediated immune disorders. Thus, the biology of FDCs has become a hot research area in the last couple of decades. In this review, we aim to provide a comprehensive overview of FDCs and their role in physiological and pathological conditions.

Inflammatory pseudotumor-like follicular dendritic cell sarcoma: Literature review of 67 cases

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: A brief report of two cases

BACKGROUND

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.

CASE SUMMARY

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

CONCLUSION

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 of the Spleen: Computed Tomography Imaging Characteristics in 5 Patients

OBJECTIVES

The purpose of this study was to retrospectively review the computed tomography (CT) and clinicopathological characteristics of inflammatory pseudotumor (IPT)-like follicular dendritic cell sarcoma (FDCS) of the spleen in 5 patients.

METHODS

Clinical, pathologic, and CT imaging findings of 5 patients with IPT-like FDCS of the spleen were reviewed and analyzed. Computed tomography imaging and pathologic features were compared.

RESULTS

Abdominal unenhanced CT revealed a well-defined hypodense mass in the spleen with complex internal architecture with focal necrosis and/or speckle-strip calcification. On postcontrast CT, slightly delayed enhancement was observed in 5 cases. Four patients had a normalized spleen. The fourth patient had lung metastasis. The fifth patient had 2 relatively small lesions as well as metastases to the spine.

CONCLUSIONS

Computed tomography imaging features of IPT-like FDCS of the spleen are distinctly different from other hypovascular splenic neoplasm; however, the definitive diagnosis requires further confirmation with needle biopsy or surgery. Inflammatory pseudotumor-like FDCS of the spleen should be suggested by using the CT imaging features of the splenic mass with evidence of metastatic disease.