© 2020 Greater Poland Cancer Centre Introduction: We describe a 35-year-old male patient showing a myeloid sarcoma (MS) of the tongue as the first manifestation of acute promyelocytic leukemia (APL). The MS can appear in all parts of the human body, but it is extremely rare in the tongue. Clinical case: The main symptoms were a pain in the tongue, asthenia, gingivorrhagia, fever. We found a tumor in the tongue, which was irregular in size and located in the posterior region of the right lateral edge of the tongue. The diagnosis of MS was made by the anatomopathological and immunohistochemical study, while the definite diagnosis of APL was confirmed by the molecular test. The treatment of APL was based on the administration of trans-retinoic acid 45 mg/m2 daily continuously and daunorubicin 60 mg/m2 every other day for 4 doses, with a favorable therapeutic response to APL and MS. Conclusion: Promyelocytic myeloid cells can infiltrate many organs extramedullary, such as the tongue, and this might precede bone marrow infiltration. The early identification of myeloid sarcoma allows to carry out an early treatment of the APL.