Hematopoietic / dendritic
Follicular dendritic cell sarcoma

Topic Completed: 1 December 2012

Revised: 23 January 2020

Copyright: 2003-2019,, Inc.

PubMed Search: Follicular dendritic cell sarcoma mediastinum

Hanni Gulwani, M.B.B.S.
Page views in 2019: 1,099
Page views in 2020 to date: 81
Cite this page: Gulwani H. Follicular dendritic cell sarcoma. website. Accessed January 26th, 2020.
  • Also called follicular dendritic reticulum cell tumor, follicular dendritic cell sarcoma
  • Reticulum cells (reticulum means netlike formation or structure) are nonlymphoid, nonphagocytic cells that capture and present antigens and immune complexes
  • Follicular dendritic reticulum cells are found in B cell zones, particularly in germinal centers
  • Interdigitating reticulum cells are found in T cell zones and are related to Langerhans cells
  • Fibroblastic reticulum cells are found in the parafollicular and deep cortex areas
Clinical features
  • Usually low grade malignant behavior, with local recurrence common and occasional distant metastases to liver or lung
  • Inflammatory pseudotumor-like FDC tumor represents a distinctive variant of FDC tumor (Am J Surg Pathol 2001;25:721)
Prognostic factors
  • Poor prognostic factors: intraabdominal location, size > 6 cm, 6 or more mitotic figures/10 HPF, atypia and coagulative necrosis
Case reports
Gross description
  • Well circumscribed, light tan and solid
  • Variable hemorrhage and necrosis
Microscopic (histologic) description
  • Fascicles, sheets, storiform or whorled patterns of a syncytium of oval and spindled cells, with pale to eosinophilic cytoplasm, oval nuclei with finely dispersed chromatin and small nucleoli
  • Often multinucleated tumor giant cells
  • Variable lymphocytes and plasma cells, often with perivascular cuffing
Microscopic (histologic) images

Images hosted on PathOut server:

Case of the Week #1:

CD21 / CD35 stain highlights ovoid spindle cells

Images hosted on other servers:

Haphazard, bland spindle cells

CD21 staining

Positive stains
Negative stains
Electron microscopy description
  • Numerous interwoven long cytoplasmic processes joined focally by desmosomes
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