RESUMEN
Interdigitating dendritic cell sarcoma (IDCS) is a very rare disease around the world and its prognosis is known to be aggressive. This reports a case diagnosed as IDCS of the axillary region treated in Soonchunhyang University Hospital. A 57-year-old female visited Soonchunhyang University Hospital with a left axillary mass. The mass was hard and fixed. Computed tomography observed a 7 cm lymph node at the left axilla, and core biopsy suspected sarcoma. In another study, there was no specific finding except the axillary lesion. Left axillary lymph node dissection (level I, II) was conducted and the pathologic report finally showed IDCS. The patient was treated with only radiotherapy and followed up without recurrence for 13 months up to now. IDCS is a very rare sarcoma that is hard to diagnose and progresses fast. Thus, treatment is very difficult. Proper treatment can be better established after more experiences.