Follicular Dendritic Cell Sarcoma with Nodal Involvement in A Young Woman: A Case Report

Follicular Dendritic Cell Sarcoma (FDCS) is a rare tumour that develops from follicular dendritic cells, which are essential to the immune system. It is more frequently seen in adults, with lymph node involvement being common, while extra-nodal occurrences are rare. This case report describes a 17-year-old female who presented with a four-year history of a progressively enlarging, painless swelling on the right side of the neck. Clinical examination indicated a soft, fluctuant, mobile, non-tender mass situated below the right mandibular angle, without regional lymphadenopathy. Imaging studies, including Magnetic Resonance Imaging (MRI) and cerebral angiography, identified a well-defined lesion in the right submandibular region with heterogeneous hyperintensity and internal cystic changes, abutting the salivary gland and carotid vessels, but without vascular invasion. Fine Needle Aspiration Cytology (FNAC) suggested differential diagnoses of paraganglioma and lymphoproliferative disorder. The patient underwent a wide local excision and biopsy under general anaesthesia. Intraoperatively, the tumour was well-encapsulated but near critical vascular structures, necessitating careful dissection. Histopathological and Immunohistochemical (IHC) evaluation confirmed the diagnosis of FDCS, a rare low-grade malignancy of histiocytic/dendritic cell origin, with nodal involvement. Postoperative Positron Emission Tomography-Computed Tomography (PET-CT) revealed no evidence of residual or metastatic disease. The patient’s recovery was uneventful, and no recurrence was detected during follow-up.