Complete Remission of Follicular Dendritic Cell Sarcoma with Adjuvant Pazopanib

Follicular Dendritic Cell Sarcoma (FDCS) is a rare neoplasm of non-hematopoietic mesenchymal origin, with less than 1000 cases documented worldwide. Pathogenesis and treatment for FDCS are not well defined. Typically, treatment involves surgical resection and radiotherapy but data on chemotherapy treatment is limited. We present a patient with FDCS of the neck who was treated surgically with adjuvant Pazopanib. The patient presented at 47 years old with a large asymptomatic neck mass and underwent surgical resection. Pathology of the mass was consistent with follicular dendritic cell sarcoma arising in association with hyaline vascular Castleman disease, with positive staining for CD21 and CD23 and variable staining for CD163 and CD68. The patient was successfully treated with adjuvant Pazopanib, a tyrosine kinase inhibitor that acts on multiple growth factor receptors. This case highlights the importance of targeting angiogenesis in the treatment of FDCS but also the importance of ascertaining the role of new immunotherapies in the targeting of soft tissue sarcomas. In the past, chemotherapy for soft tissue sarcoma has involved toxic agents such as adriamycin, gemcitabine with taxane and dacarbazine, but more research is needed into the differential sensitivity of soft tissue sarcomas to new immunotherapy treatments such as Pazopanib.