Here we report 2 patients presenting with bulky lymphadenopathy in the abdominopelvic region.

The first patient was a 64 yr old man and a lymph node biopsy from inguinal region revealed a CD23-positive, CD20-negative, CXCL13-positive and Ki67 40% positive follicular dendritic cell sarcoma. The patient received 6 courses of chemotherapy combined with PD-1 MoAb (pembrolizumab. A gemcitabine plus docetaxel regimene (GemDoc) combined with 200 mg pembrolizumab. At the end of 6 courses, PET/CT presented a metabolic CR. We continue the same cheomoimmuno regimene as maintenance treatment.

The second patient is a 44 year old man who has an intraabdominal bulky tumor and multiple hepatic metastasis. Core biopsies from liver lesions and intra-abdominal mass revealed FDCS. The patient took the first course of the same regimene of chemoimmunotherapy composed of a GemDoc+pembrolizumab and felt comfortable because of the decrease in tumor sizes.

A very rare entity, FDCS has no a standart treatment, yet. We combine a second line sarcoma regimen (GemDoc) with Anti-PD1 Ab, pembrolizumab as induction systemic treatment and followed by a maintenance Pembrolizumab. This chemoimmunotherapy regimen suggest that it will work in FDCS patients who have intermediate PD-L1 expression in tumor cells.