Interdigitating dendritic cell sarcoma presenting in the sigmoid colon mesentery: A case report and literature review

RATIONALE: Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare disease. It commonly occurs in middle-aged males and mainly involves the lymph nodes. Pathological examination plays an important role in differentiating from other tumors, but far less published literature focuses on the imaging characteristics of IDCS. PATIENT CONCERNS: Here, we reported a case of IDCS in a 52-year-old male involving the pelvis with medical imaging and pathologic findings. DIAGNOSES: Preoperative unenhanced CT scan revealed a 6.0 × 6.3 × 8.0 cm mass with density equal to that of adjacent muscle, located in the pelvis. On contrast-enhanced CT images, the tumor presented apparent homogeneous enhancement. CT angiography showed that the tumor was supplied by the branches of inferior mesenteric artery. Pelvic magnetic resonance imaging manifested a lobulated solid mass with low signal on T1-weighted and intermediate to high signal on T2-weighted images. Simultaneously, significantly high signal intensity was exhibited on the diffusion-weighted images. This patient underwent operative resection of the tumor. The pathologic diagnosis was IDCS. INTERVENTIONS: This patient underwent operative resection of the tumor. The resection margins were negative for the neoplastic proliferation and no distant metastases were found. The patient did not receive advanced radiotherapy or chemotherapy. OUTCOMES: Three months after surgery, the follow-up CT scan did not reveal any recurrence or metastases. LESSONS: This case adds to the experience with IDCS by summarizing its characteristics as well as reviewing the literature.