First pediatric case of follicular dendritic cell sarcoma in the parotid gland: a case report.

Background: Follicular dendritic cell sarcoma (FDCS) is an extremely rare malignancy originating from antigen-presenting dendritic cells of the B-cell follicles. While typically affecting adults and occurring in lymphoid tissues such as tonsils and the Waldeyer's ring, FDCS in the parotid gland is exceptionally rare, with only five adult cases reported to date. To our knowledge, this is the first documented pediatric case of FDCS of the parotid gland. Materials and methods: We present the case of a 13-year-old male with a progressively enlarging mass in the right parotid region. Diagnostic workup included imaging (MRI and CT), biopsy, and immunohistochemical staining positive for CD21 and CD23. The patient underwent systemic chemotherapy with a CCABE regimen (cisplatin, cyclophosphamide, bleomycin, etoposide, and doxorubicin), followed by external beam radiotherapy using LINAC at 40 Gy/20 fractions. Response to treatment was monitored through serial MRI and CT imaging. Results: The patient showed significant regression of both the primary tumor and pulmonary metastases following combined chemoradiotherapy. His quality of life markedly improved, and follow-up imaging confirmed resolution of the primary lesion. However, metastatic recurrence in the lungs was later observed, though the primary site remained disease-free. The patient was restarted on the same chemotherapy regimen. Conclusion: This case represents the first known pediatric FDCS of the parotid gland and demonstrates that a combination of systemic chemotherapy and targeted radiotherapy can achieve promising results, even in metastatic disease. Long-term follow-up is required to evaluate sustained response and monitor for recurrence or late treatment complications.