Lymph nodes & spleen, nonlymphoma

Lymph node & spleen-nonlymphoid neoplasms

Follicular dendritic cell sarcoma (FDCS)

Editor-in-Chief: Debra L. Zynger, M.D.
Aishwarya Ravindran, M.B.B.S.
Karen L. Rech, M.D.

Last author update: 29 October 2019
Last staff update: 1 August 2023 (update in progress)

Copyright: 2003-2023,, Inc.

PubMed Search: Follicular dendritic cell sarcoma [title] lymph node "loattrfree full text"[sb]

Aishwarya Ravindran, M.B.B.S.
Karen L. Rech, M.D.
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Cite this page: Ravindran A, Rech KL Follicular dendritic cell sarcoma (FDCS). website. Accessed October 2nd, 2023.
Definition / general
  • Rare mesenchymal neoplasm arising from follicular dendritic cells of lymphoid follicles at nodal and extranodal sites
  • Nodal follicular dendritic cell sarcoma first characterized in 1986 (Am J Pathol 1986;122:562)
  • Extranodal follicular dendritic cell sarcoma (oral cavity, soft palate, tonsil) first described in 1994 (Am J Surg Pathol 1994;18:148)
Essential features
  • Presents as a painless solid mass involving nodal and extranodal sites
  • Surgical resection results in complete remission in a majority of cases; however, about a third of cases recur locally
  • Behaves as a low grade sarcoma; can metastasize by hematologic spread to bone, lungs, liver
  • Immunohistochemistry is essential for diagnosis; clusterin is a highly sensitive and specific marker
  • Previous designation as follicular dendritic cell tumor in WHO classification prior to 2008
ICD coding
  • ICD-10: C96.4 - sarcoma of dendritic cells (accessory cells)
  • Nodal sites: cervical (most common), second most common is axillary or supraclavicular lymph nodes
  • Extranodal involvement includes a wide variety of sites including head and neck, gastrointestinal tract, liver and spleen (Arch Pathol Lab Med 2008;132:1683)
  • Risk factors are unknown in most cases
  • May arise in the context of follicular dendritic cell proliferation in Castleman disease, hyaline vascular variant
  • Minor subset of cases involving the liver or spleen show association with Epstein-Barr virus (inflammatory pseudotumor-like follicular dendritic cell sarcoma) (Am J Surg Pathol 2001;25:721)
Clinical features
  • Nodal and extranodal involvement characterized by slow growing, painless solid mass
  • Abdominal masses may be associated with worsening abdominal pain
  • B symptoms are usually absent
  • Rarely, may be associated with paraneoplastic autoimmune multiorgan syndrome (PAMS) (Am J Surg Pathol 2018;42:1647)
Radiology images

Images hosted on other servers:

Small bowel and liver tumor

Cystic neck lesion

Liver mass

Prognostic factors
  • Low grade sarcoma that has significant recurrence rate (~40 - 50%) and can metastasize (Cancer 1997;79:294)
  • Poor prognostic factors include size of tumor (> 6 cm), nuclear pleomorphism, increased mitoses (> 5/10 HPF), necrosis and intra-abdominal location (Arch Pathol Lab Med 2017;141:596)
  • Inflammatory pseudotumor-like follicular dendritic cell sarcoma of the liver or spleen shows indolent behavior without recurrence (Am J Surg Pathol 2001;25:721)
  • Association with paraneoplastic autoimmune multiorgan syndrome follows an aggressive course related to respiratory morbidity and mortality (Am J Surg Pathol 2018;42:1647)
Case reports
Clinical images

Images hosted on other servers:

Neck swelling

Paraneoplastic pemphigus

Gross description
  • Usually round to ovoid, well circumscribed fleshy solid mass (Arch Pathol Lab Med 2016;140:186)
  • Size ranges from 1 - 15 cm, largely dependent on the site of the tumor
  • May show areas of hemorrhage and necrosis
Gross images

Images hosted on other servers:

Mesentery tumor

Small bowel and liver tumor

Well circumscribed neck tumor

Liver tumor

Microscopic (histologic) description
  • Oval to spindled cells with dispersed chromatin, small nucleoli, eosinophilic and fibrillar cytoplasm with syncytial borders arranged in fascicles, whorls or storiform patterns
  • Often binucleate or occasional multinucleate forms, nuclear pseudoinclusions
  • Perivascular lymphocyte cuffs and admixed population of lymphocytes, eosinophils, plasma cells or neutrophils may be present (Am J Surg Pathol 2004;28:988)
Microscopic (histologic) images

Contributed by Aishwarya Ravindran, M.B.B.S. and Karen L. Rech, M.D.

Storiform growth

Ovoid cells mixed with lymphocytes







Virtual slides

Contributed by Genevieve M. Crane, M.D., Ph.D.

With aggressive B cell lymphoma

Positive stains
Electron microscopy description

AFIP images

Numerous interdigitating processes

Molecular / cytogenetics description
  • Proposed molecular pathogenesis involves activation of nuclear factor κβ genes as a consequence of recurrent loss of function alterations in nuclear factor κβ regulatory genes (NFKBIA, CYLD), cell cycle progression genes (CDKN2A, RB1) and genes involved in immune evasion (CD274, PDCD1LG2) (Mod Pathol 2016;29:67)
  • Genetic alterations including copy number variations, somatic mutations involving oncogenes / tumor suppressors (ZBTB7A, SETD2), chromatin remodeling genes (CABIN1, NCAPH) and other genes have been reported (Blood Adv 2018;2:481)
  • BRAF V600E mutation present in ~19% cases (Histopathology 2014;65:261)
  • Cytogenetically adverse with abnormal karyotype (In Vivo 2013;27:211)
Sample pathology report
  • Lymph node, left neck, excisional biopsy:
    • Follicular dendritic cell sarcoma, completely excised (see comment)
    • Comment: Lymph node architecture is partially effaced by an abnormal population of epithelioid to spindle shaped cells in a whorling pattern. The neoplastic cells have ovoid nuclei, delicate chromatin, small nucleoli and abundant eosinophilic cytoplasm. They are variably admixed with small lymphocytes. Immunohistochemical stains were performed on paraffin sections of the left neck lymph node (CD21, CD23, CD31, CD34, CD35, CD45, clusterin, CXCL13, epithelial membrane antigen, melanA, keratin (AE1 / AE3), HMB45, S100 and terminal deoxynucleotidyl transferase). The abnormal cells are positive for CD21, CD23, CD35, clusterin and CXCL13. There are small numbers of terminal deoxynucleotidyl transferase positive (TdT) cells mixed with the tumor. The neoplastic cells are negative for the other markers tested. Morphology and immunohistochemical stains indicate the diagnosis of follicular dendritic cell sarcoma.
Differential diagnosis
  • Interdigitating dendritic cell sarcoma
    • Histologically may be indistinguishable from follicular dendritic cell sarcoma and immunohistochemical studies are required for a definite diagnosis
    • Positive for S100, negative or focally positive for clusterin (Am J Surg Pathol 2004;28:988)
  • Langerhans cell histiocytosis
    • Langerhans cells are oval and recognized by their grooved, folded or indented nuclei with fine chromatin, inconspicuous nucleoli and thin nuclear membrane with moderately abundant and slightly eosinophilic cytoplasm
    • Positive for CD1a and langerin
  • Kaposi sarcoma
    • Atypical spindled cells form slit-like vascular spaces containing red blood cells
    • Positive for HHV8
  • Spindle cell thymoma
    • Site involved is usually anterior mediastinum
    • Bland spindled cells with fascicular to whorling growth pattern
    • Positive for keratin (AE1 / AE3)
  • Metastatic carcinoma
    • Usually epithelioid cells in sheets, clusters or single cells with marked nuclear atypia
    • Positive for keratin (AE1 / AE3)
  • Metastatic melanoma
    • Variable cytology including epithelioid or spindled cells with nuclear atypia and prominent nucleoli; cytoplasm may contain brown pigment (melanin)
    • Positive for S100 and MelanA
  • Inflammatory myofibroblastic tumor
    • Spindled myofibroblasts and fibroblasts with bland nuclei
    • Positive for ALK1
  • Pleomorphic sarcoma
    • Pleomorphic cells with a spectrum of cytology and may include spindled, plasmacytoid, epithelioid or multinucleated forms
    • Negative for clusterin, CXCL13, CD21, CD23, CD35
Board review style question #1
An 88 year old man presented with significant snoring and increasing sleep apnea. Laryngoscopy revealed a pharyngeal mass. CT head and neck with IV contrast revealed a 6 cm enhancing mass in the right parapharyngeal space. An excisional biopsy was performed. Based on the immunophenotype, what is the diagnosis?
  1. Follicular dendritic cell sarcoma
  2. Interdigitating dendritic cell sarcoma
  3. Langerhans cell sarcoma
  4. Pleomorphic sarcoma
Board review style answer #1
Board review style question #2
Which of the following immunostains is highly sensitive and specific for follicular dendritic cell tumor?
  1. CD1a
  2. Clusterin
  3. Fascin
  4. S100
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