FDCS is an exceedingly rare neoplasm with very few cases reported in the literature. FDCSs are described as abnormal proliferation of accessory cells in the lymphatic system having low malignant potential.3,4 FDCS most commonly involves cervical nodes. However, one-third of cases are extranodal in origin, mainly involving the head and neck sites, gastrointestinal tract, soft tissue, and mediastinum.4,15
Extranodal intra-abdominal FDCS is an extremely rare entity, involving the liver and spleen, and it is rarer with tumors of the gastrointestinal tract and mesentery/omentum.5,6 FDCS typically affects middle-aged adults with no sex predilection. The most common clinical presentation is that of a painless, slow growing swelling.4 Imaging can be an initial tool for diagnosis and staging. Smaller homogeneous masses are usually seen on CT scan; however, heterogeneity as a result of necrosis or hemorrhagic areas have been reported in 80% of cases.7
Grossly, FDCSs are well-circumscribed pink or tan-gray nodular to bosselated solid masses with size ranging from 1 to 20 cm. Intra-abdominal tumors can measure up to 20 cm.8 Pathological diagnosis cannot be based solely on morphological grounds but must be confirmed by IHC and preferably supported by ultrastructural studies. Most widely used FDCS markers are CD21, CD23, CD35, and D2-40 (podoplanin), which can distinguish FDCS from other spindle-cell neoplasms.1,9–11 FDCSs have been regarded as low-grade indolent malignant neoplasms with local recurrences and low risk of metastasis, behaving like a low-grade soft-tissue sarcoma. Extrahepatic abdominal/pelvic lesions showed high recurrence and also higher mortality rates.12 Chan et al13 considered FDCS to be of intermediate grade with a substantial risk of metastasis to the lung, liver, peritoneum, and lymph node and also showed a higher recurrence rate in intra-abdominal locations. However, Perez-Ordonez et al8 considered FDCS to be more aggressive.
FDCS can often be misdiagnosed. There are reports of 30% to 58% misdiagnosed cases, especially when arising from extranodal sites. FDCS arising in the gastrointestinal tract commonly may be mistaken for kit-negative GIST, but dense lymphocytic infiltrates are uncommon in GIST; GIST is also negative for CD21 and CD35, whereas FDCS is negative for CD34 and DOG-1 (Table 1).10,14 Two most reliable IHC markers are CD21 and CD23, which have led to improve the accuracy of this rare entity underlying the importance of IHC in diagnosis. Recently, 2 novel, highly sensitive and specific markers for FDCS, follicular dendritic cell–secreted protein and serglycin, have been identified.15
Author contributions: A.M. Gupta wrote the manuscript. M. Goel and S. Patkar edited the manuscript. A. Sahay and S.P. Janjal interpreted the pathology slides. S. Patkar is the article guarantor.
Financial disclosures: None to report.
Informed consent was obtained for this case report.
1. Chan JK, Tsang WY, Ng CS. Follicular dendritic cell tumor and vascular neoplasm complicating hyaline-vascular Castleman's disease. Am J Surg Pathol. 1994;18(5):517–25.
2. Zhonghua B, Li X, Za Z. Clinicopathologic study of intraabdominal extranodal follicular dendritic cell sarcoma [Chinese]. Zhonghua Bing Li Xue Za Zhi. 2007;36(10):660–5.
3. Monda L, Warnke R, Rosai J. A primary lymph node malignancy with features suggestive of dendritic reticulum cell differentiation. A report of 4 cases. Am J Pathol. 1986;122(3):562–72.
4. Kairouz S, Hashash J, Kabbara W, McHayleh W, Tabbara IA. Dendritic cell neoplasms: An overview. Am J Hematol. 2007;82(10):924–8.
5. Moriki T, Takahashi T, Wada M, Ueda S, Ichien M, Yamane T, Hara H. Follicular dendritic cell tumor of the mesentery. Pathol Res Pract. 1997;193(9):629–2.
6. Li Z, Jin K, Yu X, Teng X, Zhou H, Wang Y, Teng L, Cao F. Extranodal follicular dendritic cell sarcoma in mesentery: A case report. Oncol Lett. 2011;2(4):649–52.
7. Li J, Geng ZJ, Xie CM, et al. Computer tomography imaging findings of abdominal follicular dendritic cell sarcoma: A report of 5 cases. Medicine. 2016;95(1):e2404.
8. Perez Ordonez B, Erlandson RA, Rosai J. Follicular dendritic cell tumor: Report of 13 additional cases of a distinctive entity. Am J Surg Pathol. 1996;20(8):944–55.
9. Wang RF, Han W, Qi L, Shan LH, Wang ZC, Wang LF. Extranodal follicular dendritic cell sarcoma: A clinicopathological report of four cases and a literature review. Oncol Lett. 2015;9(1):391–8.
10. Shia J, Chen W, Tang LH, et al. Extranodal follicular dendritic cell sarcoma: Clinical, pathologic, and histogenetic characteristics of an under recognized disease entity. Virchows Arch Int J Pathol. 2006;449(2):148–58.
11. Hollowood K, Stamp G, Zouvani I, Fletcher CD. Extranodal follicular dendritic cell sarcoma of the gastrointestinal tract. Morphologic, immunohistochemical and ultrastructural analysis of two cases. Am J Clin Pathol. 1995;103(1):90–7.
12. Li L, Shi YH, Guo ZJ, et al. Clinicopathological features and prognosis assessment of extranodal follicular dendritic cell sarcoma. World J Gastroenterol. 2010;16(20):2504–19.
13. Chan JK, Fletcher CD, Nayler SJ, Cooper K. Follicular dendritic cell sarcoma. Clinico pathological analysis of 17 cases suggesting a malignant potential higher than currently recognized. Cancer. 1997;79(2):294–313.
14. Wu A, Pullarkat S. Follicular dendritic cell sarcoma. Arch Pathol Lab Med. 2016;140(2):186–90.
15. Dutta A, Arun P, Roy P, Arun I. Cytological diagnosis of follicular dendritic cell sarcoma: A case report and review of literature. Cytopathology. 2018;29(5):461–7.
16. Saygin C, Uzunaslan D, Ozguroglu M, Senocak M, Tuzuner N. Dendritic cell sarcoma: A pooled analysis including 462 cases with presentation of our case series. Crit Rev Oncol Hematol. 2013;88(2):253–71.
17. Gounder M, Desai V, Kuk D, et al. Impact of surgery, radiation and systemic therapy on the outcomes of patients with dendritic cell and histiocytic sarcomas. Eur J Cancer. 2015;51(16):2413–22.
18. Sasaki M, Izumi H, Yokoyama T, Kojima M, Hosono A. Follicular dendritic cell sarcoma treated with a variety of chemotherapy. Hematol Oncol. 2017;35(4):905–8.
19. Conry RM. Response of follicular dendritic cell sarcoma to gemcitabine and docetaxel: Report of two cases and literature review. Clin Sarcoma Res. 2014;4:6.
20. Hensley ML. Update on gemcitabine and docetaxel combination therapy for primary and metastatic sarcomas. Curr Opin Oncol. 2010;22(4):356–61.