Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 56 11 2019 01 16 726 728 EN Flavia Faria Pediatric Oncologist, Children’s Hospital of Brasília José Alencar, Brasília-DF, Brazil. Vitorino Modesto dos Santos Department of Internal Medicine, Armed Forces Hospital and Catholic University of Brasília, Brasília-DF, Brazil. Lara Vieira da Silva Meira Department of Internal Medicine, Ex-Intern, Catholic University of Brasília, Brasília-DF, Brazil. 2017 04 24 2017 04 30 Histiocytic sarcoma is a rare hematopoietic malignancy that originates from histiocytes, and may involve lymph nodes and extranodal sites such as the spleen, head and neck, skeleton, liver, breast, bone marrow, mediastinum, pancreas, skin, lung, kidney, central nervous system, testis, gastrointestinal tract, and uterus. The involvement of the nasal cavity is considered extremely rare. The prognosis is poor, even with chemotherapy, and the survival time is usually two years. We report the case of a 16-year-old-male with primary histiocytic sarcoma of the nasal cavity. The diagnosis was based on classical histopathology and immunohistochemical findings. This malignancy has not shown consistent satisfactory responses to chemotherapy regimens. https://acta.tums.ac.ir/index.php/acta/article/view/6396 https://acta.tums.ac.ir/index.php/acta/article/download/6396/5185