Mediastinum
Other malignancies
Follicular dendritic cell tumor

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 21 June 2018, last major update December 2012

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Follicular dendritic cell tumor mediastinum

Cite this page: Gulwani, H. Follicular dendritic cell tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumfolliculardendriticcell.html. Accessed October 17th, 2018.
Terminology
  • 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
Sites
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)
Diagnosis
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