Interdigitating Dendritic Cell Sarcoma of the Small Intestine Presenting as Spontaneous Hemoperitoneum - A Rare Case Report.

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm arising from the antigen-presenting cells of the immune system. It usually involves the lymph nodes, and extranodal sites are rarely affected. Here, we report a first known case of spontaneous hemoperitoneum caused by the rupture of IDCS of the small bowel. A 61-year-old male presented with complaints of abdominal pain and fever for 3 days and breathlessness for 1 day. Ultrasound abdomen revealed a 15 cm × 7 cm heterogeneous collection with thick septations in the periumbilical region. Diagnostic peritoneal lavage revealed hemoperitoneum and gangrenous bowel. Emergency laprotomy was done and it revealed a friable mass arising from the ileum. Resection of 2 ft of the ileum and double-barrel ileostomy was done. Immunohistochemical analysis revealed a positivity of S100 and leukocyte common antigen). A diagnosis of IDCS was made. The patient had an uneventful postoperative recovery and planned for postoperative chemotherapy.