Follicular Dendritic Cell Sarcoma
Follicular dendritic cell sarcoma that presented as a small bowel mass and was thought to be a gastrointestinal stromal tumor clinically and on imaging studies. Immunohistochemically, it was strongly positive for CD21, CD23, and CD35. The negative markers included CD117, CD34, CD68, CD163, CD20, CD3, CD43, S-100, and desmin.
The image shows epithelioid cells with moderate amount of fibrillar eosinophilic cytoplasm and indistinct borders. The nuclei show moderate pleomorphism with irregular shapes and vesicular chromatin. The tumor cells are admixed with a few small lymphocytes and plasma cells.