A Rare Case of Follicular Dendritic Cell Sarcoma of Tonsil-Clinical Report.

Follicular dendritic cells (FDC) are mesenchymal-derived dendritic cells in B-cell follicles. They play a crucial role in initiating and maintaining the adaptive immune response of B-cells. In 1986, Dr. Juan Rosai first reported a series of neoplasms showing features of FDC and defined it as a Follicular Dendritic Cell Tumor, subsequently renamed as "sarcoma" (FDCS). The diagnosis of FDCS is based on a combination of clinical examination, histopathologic features, electron microscopy, and confirmation through immunohistochemical studies. Here, we report a case of a 55-year-old female who presented to our OPD with complaints of recurrent throat pain and difficulty during swallowing for the past 2 years, along with a foreign body sensation in the throat with occasional minimal bleeding from the left tonsillar region. Left ECA ligation with left tonsillectomy by cauterization method was done under GA. The Histopathological report came to be Follicular Dendritic Cell Sarcoma of the tonsil after IHC confirmation. After the diagnosis, the patient received post-operative radiotherapy. The patient is on a six-month follow-up, which is uneventful. FDCS is a rare tumor, particularly in extranodal sites. The diagnosis must be kept in mind when confronted with uncommon histological features in lymphoid tissue, and the final diagnosis can be rendered only after proper immunohistochemical examination.