Cytomorphological Findings of Follicular Dendritic Cell Sarcoma on Fine-Needle Aspiration Cytology

Abstract

Background: Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm arising from follicular dendritic cells of germinal centers. The most common site of origin is lymph nodes and it may mimic a variety of tumors at that location, including carcinomas and sarcomas. Diagnosis is frequently missed on cytology as there are very few case reports describing the cytological characteristics of the lesion. Even on histology, a high degree of suspicion is required for an appropriate diagnosis. Case: A 60-year-old male presented with a gradually increasing left submandibular mass that had been present for 3 months. Fine-needle aspiration cytology (FNAC) was performed, showing many clusters as well as scattered epithelioid cells with spindled to oval nuclei, nuclear pleomorphism, grooves, inclusions, and uniformly dispersed mature lymphocytes throughout the smears. The diagnosis of FDCS was suspected and was confirmed on histopathology and immunohistochemistry. Conclusion: FNAC can be a cheap, easy, and helpful tool in obtaining a diagnosis of FDCS as there are few characteristic cytological features that are better recognized than histology.

Follicular dendritic cell sarcoma: Cytomorphologic features and diagnostic challenges

“…The diagnosis of FDSC on cytology fine needle aspiration (FNA) is challenging and misdiagnosis is common. Ojha et al, found that out of 15 FNA cases of FDCS, only three cases were diagnosed on cytology 9 . Ren et al, also showed similar findings in their study; only two of ten cases of FDCS were diagnosed on cytology, both of which had a prior known history (one was recurrent and the other was metastatic) 10 …”

Fine needle aspiration of an intranodal follicular dendritic cell sarcoma: A case report with molecular analysis and review of the literature

“…The diagnosis of FDCS may be challenging as its cytologic, histologic, and immunohistochemical features overlap with other entities in the differential diagnosis. A recent literature review of 15 FNA cases of FDCS is a testament to this, as it found that only three cases were diagnosed on cytology 14 . It therefore requires a high index of suspicion to prompt the appropriate workup with FDC‐specific markers.…”

Follicular dendritic cell sarcoma of the cervical lymph node diagnosed on fine needle aspiration cytology

“…Follicular dendritic cell sarcoma tumours are defined as histiocytic and dendritic cell tumours which develop in nodal and extranodal lymphoid tissue 3 . Physiologically, follicular dendritic cells serve as antigen‐presenting cells to B‐lymphocytes and provide structural support to lymphoid follicles.…”

“…The tumour cells are positive for CD21, CD23, CD35, clusterin, fascin and vimentin, and variably express EMA, S100 and CD68 immunostaining. A recent review of literature found 22 cytological reports of FDCS, and only five cases were diagnosed correctly on cytology, three of which were known cases of FDCS 3,6‐9 …”