Primary follicular dendritic cell sarcoma of the kidney – a case report of a rare tumor with emphasis on diagnostic pitfalls

Abstract Background Follicular dendritic cell sarcoma (FDCS) is a rare low-grade tumor of the lymph nodes, but roughly one-third of the cases emerge from extranodal sites, posing diagnostic challenges. Case presentation In this report, we present the case of a 59-year-old lady who complained of rena...

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Bibliographic Details
Main Authors: Tamás Pancsa, Borbála Dénes, Áron Somorácz, Dóra Kelemen, Ferenc Salamon, Fanni Sánta, Levente Kuthi
Format: Article
Language:English
Published: BMC 2024-01-01
Series:Diagnostic Pathology
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Online Access:https://doi.org/10.1186/s13000-024-01444-x
Description
Summary:Abstract Background Follicular dendritic cell sarcoma (FDCS) is a rare low-grade tumor of the lymph nodes, but roughly one-third of the cases emerge from extranodal sites, posing diagnostic challenges. Case presentation In this report, we present the case of a 59-year-old lady who complained of renal colic. During investigation, a kidney tumor was discovered. A radical nephrectomy was performed, and histological examination identified the tumor as a sarcomatoid renal cell carcinoma. The case was then referred to a genitourinary pathologist for further evaluation. The tumor cells exhibited positive staining for CD21, CD23, somatostatin receptor 2 A, and MDM2 expression. Additionally, MDM2 gene amplification was confirmed by the FISH study. Ultimately, the tumor was diagnosed as a primary renal FDCS. The patient was placed under active oncological surveillance and did not receive any further therapy. Remarkably, after 91 months of follow-up, she remains tumor-free. Conclusion This case represents a well-documented primary renal FDCS. Our aim in presenting this extremely rare tumor is to enhance awareness and highlight the importance of considering FDCS in the differential diagnosis.
ISSN:1746-1596