Follicular Dendritic Cell Sarcoma



Follicular Dendritic Cell Sarcoma


Sa A. Wang, MD










Lymph node involved by follicular dendritic cell (FDC) sarcoma. The neoplastic cells have indistinct cell borders, a moderate amount of eosinophilic cytoplasm, and oval or elongated bland nuclei.






Papanicolaou-stained scrape preparation of FDC sarcoma. The neoplastic cells are large and oval or spindle-shaped, with inflammatory cells in the background.


TERMINOLOGY


Abbreviations



  • Follicular dendritic cell (FDC) sarcoma


Synonyms



  • FDC tumor


  • Dendritic reticulum cell sarcoma


Definitions



  • Neoplastic proliferation of follicular dendritic cells



    • Immunophenotype supports FDC lineage


ETIOLOGY/PATHOGENESIS


Normal FDCs



  • Localized to B-cell areas in primary and secondary lymphoid follicles



    • Form a meshwork via cell to cell attachments and desmosomes


    • Do not migrate


  • Trap and present antigens to B cells that are involved in B-cell proliferation and differentiation



    • Store antigen on cell surface as immune complexes


  • Closely related to bone marrow stromal progenitors



    • Have features of myofibroblasts


Etiology of FDC Sarcoma



  • Unknown in most cases


  • Small subset of cases of FDC sarcoma are associated with Castleman disease (CD)



    • Hyaline-vascular variant


    • FDC “dysplasia” has been reported in hyaline-vascular CD


  • Inflammatory pseudotumor-like variant of FDC sarcoma



    • Consistently associated with Epstein-Barr virus (EBV)


    • EBV is present in monoclonal form


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare


  • Age



    • Adults; median age: 40-50 years


  • Gender



    • Overall, no gender preference



      • Inflammatory pseudotumor-like variant shows female predominance


  • Ethnicity



    • No known predisposition


Presentation



  • Often presents as slow-growing, painless mass



    • Lymph nodes



      • Cervical lymphadenopathy is most common


      • Other lymph node groups: Axillary, mediastinal, mesenteric, and retroperitoneal may or may not present


    • Extranodal sites



      • Waldeyer ring is most common, such as tonsil, oral cavity


      • Gastrointestinal tract


      • Soft tissue, skin


      • Thyroid, breast, mediastinum


      • Liver and spleen


    • Inflammatory pseudotumor-like variant FDC sarcoma



      • Often arises in intraabdominal sites: Liver, spleen, and peripancreatic area


  • Systemic symptoms



    • Uncommon in most patients with FDC sarcoma


    • Systemic symptoms are common in patients with inflammatory pseudotumor-like variant



      • Weight loss and fever


    • Paraneoplastic pemphigus can occur rarely



Treatment



  • Most patients are treated by complete surgical excision



    • With or without adjuvant radiotherapy or chemotherapy



      • Various chemotherapy regimens have been used with limited success


      • Adjuvant radiotherapy may prolong disease-free survival


Prognosis



  • Most cases behave like low- to intermediate-grade soft tissue sarcoma



    • Local recurrences occur in > 50% of patients


    • Metastases occur in ˜ 25% of patients



      • Lymph nodes, lung, liver


    • 10-20% of patients ultimately die of the disease after many years


  • Poor prognostic indicators



    • Large tumor size (> 6 cm)


    • Intraabdominal location



      • Often in liver, spleen, or peripancreatic or retroperitoneal lymph nodes


      • Inflammatory pseudotumor-like variant of FDC sarcoma is more indolent


    • High-grade histologic features


IMAGE FINDINGS


General Features



  • FDC sarcoma cannot be distinguished from other malignant processes by imaging


  • CT and MR



    • Mass lesion, expansile


    • ± invasion of surrounding structures


  • Positron emission tomography (PET) shows abnormal radiotracer uptake


MACROSCOPIC FEATURES


Size



  • Mean: 5 cm; range: 1-21 cm


MICROSCOPIC PATHOLOGY


Histologic Features

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Follicular Dendritic Cell Sarcoma
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