Rare metastatic primary intra-abdominal follicular dendritic cell sarcoma poorly responsive to chemotherapy: A case report

ABSTRACT

Background@#Follicular dendritic cell sarcoma (FDCS) accounts for about 0.4% of soft tissue sarcomas. Approximately onethird of cases occur in extranodal sites and about 28% of extranodal FDCS may metastasize. Intra-abdominal occurrence is rare and there is limited published data to guide oncologists on how to best treat this malignancy.@*Case Presentation@#This is a case of a 33-year-old female who came in due to incidental finding of a left supraclavicular mass with 2-year history of early satiety. Neck node biopsy revealed a poorly differentiated malignant tumor with positive staining for CD21, CD23, vimentin and S100 consistent with FDCS. PET-CT revealed an intensely FDG-avid large mass in the left upper abdomen with signs of necrosis and mass effect. The patient was given three different chemotherapy regimens that included (1) gemcitabine/docetaxel, (2) single agent doxorubicin and (3) ifosfamide/etoposide, but she progressed on all these. Off-label use of bendamustine was then offered and after just the first cycle, the patient reportedly regained strength and was able to get up from wheelchair with noted interval decrease in size of the cervical mass. Unfortunately, the patient deteriorated and succumbed to infection and multiple pulmonary embolisms.@*Conclusion@#Intra-abdominal FDCS is a rare malignancy with heterogenous outcomes with no uniform treatment strategy at present. Molecular tumor board discussion and multi-disciplinary approach in extranodal FDCS is important in the diagnosis and management. Patients with multiple poor prognostic factors are at risk for tumor recurrence, metastasis, and death.