Follicular Dendritic cell sarcoma of caecum in a young boy presenting as Intussusception

Abstract

Background: Follicular dendritic cell sarcoma (FDCS) is a rare tumor derived from follicular dendritic cells (FDC) occurring in lymph nodes and extranodal sites. It is usually regarded as an indolent tumor with a tendency of local recurrence but a low risk of metastasis. Common extranodal sites are liver, lung, tonsil, spleen, soft tissue, and mediastinum. Extranodal FDCS of gastrointestinal tract (GIT) is exceedingly rare, with just 36 cases reported in the literature. Methods: We report an unusual case of FDCS of caecum in a 13-year-old boy who presented as intussuception. On histology, it posed a diagnostic challenge for us. An inconclusive initial immunohistochemistry (IHC) lead us to suspect FDCS which was confirmed by FDC markers. Conclusions: The diagnosis of FDCS at extranodal site like GIT is all the more challenging because of its rarity, morphologic heterogeneity, and lack of awareness.