Complete response of a patient with advanced primary splenic histiocytic sarcoma by treatment with chemotherapeutic drugs selected using the collagen gel droplet-embedded culture drug sensitivity test.

A 69-year-old man presented with multiple nodules on the spleen and liver that had been detected by computed tomography (CT). A liver tumor biopsy was performed, and the patient was diagnosed to have histiocytic sarcoma (HS). Splenectomy was performed, and the chemosensitivity of the spleen tumor was measured using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST). Hepatic arterial infusion chemotherapy was administered, based on the results of the CD-DST. The patient achieved complete remission (CR) after this therapy and remained alive without recurrence at the final follow-up. This is the first known case of CR in response to chemotherapy for advanced splenic HS.