Interdigitating Dendritic Cell Sarcoma of the Rectum: A Case Report with Review of the Literature

Abstract Interdigitating dendritic cell sarcoma (IDCS) is a rare cancer that arises from dendritic cells, which function as antigen-presenting cells within the immune system. The manifestation of IDCS in the gastrointestinal tract, particularly the rectum, is exceedingly rare. We describe a case of extranodal IDCS in the rectum of a young female patient who presented with hematochezia for 18 months. Her clinical assessment was performed in August 2023 at a tertiary oncology center at Rajiv Gandhi Cancer Institute and Research Centre in New Delhi. Clinical workup included digital rectal examination, sigmoidoscopy, pelvic magnetic resonance imaging, and positron emission tomography/computed tomography. Biopsy via sigmoidoscopy suggested a spindle cell tumor of neural origin. The patient underwent transanal tumor excision. Histopathology and immunohistochemistry confirmed IDCS with S100 positivity. The patient was placed on regular surveillance with follow-up every 3 months. A comprehensive literature review was conducted to assess existing reports of gastrointestinal IDCS, especially rectal involvement. Very few cases have been documented, with only two other confirmed rectal IDCS cases reported to date. This case emphasizes the accurate diagnosis and prompt management of rectal IDCS, adding to the limited existing literature.