Myeloid sarcoma (MS), also known as granulocytic sarcoma or chloroma, is a rare extramedullary tumor composed of myeloblasts. It may occur de novo, concurrently with acute myeloid leukemia (AML), or as a relapse of previously treated AML. Oral cavity involvement is rare, and isolated presentations without bone marrow disease pose significant diagnostic challenges . MS is biologically considered equivalent to AML and should be treated accordingly, even in the absence of systemic disease .

A 51-year-old woman presented with left facial swelling and dysphagia. MRI revealed a large mass in the left retromolar trigone extending to the skull base and infratemporal region with associated mandibular bone destruction. Incisional biopsy showed sheets of immature myeloid cells. Immunohistochemistry was positive for CD117, CD34, myeloperoxidase (MPO), and CD99, with a Ki-67 proliferation index of ∼40%, confirming myeloid sarcoma. PET-CT revealed a hypermetabolic mass (SUVmax 7.27) and ipsilateral cervical lymphadenopathy but no systemic FDG-avid disease. Bone marrow biopsy showed no leukemic infiltration The patient was treated for acute myeloid leukemia and was started on a 7+3 chemotherapy protocol. The patient is being monitored during the post-treatment cytopenic period.

ConclusionThis case highlights the diagnostic complexity of isolated myeloid sarcoma in an unusual location. Comprehensive immunophenotypic analysis is essential for diagnosis. Although marrow was uninvolved, the patient was initiated on AML-type induction chemotherapy due to the high risk of progression . Early systemic treatment, rather than localized therapy alone, is critical to avoid transformation into overt leukemia . Systemic chemotherapy using AML-like regimens should be commenced early, even in nonleukemic disease. Surgery and/or radiotherapy may be indicated for symptomatic lesions or tumors causing local organ dysfunction or obstruction. Allogeneic hematopoietic stem cell transplantation has demonstrated promising results, particularly in patients who achieved complete remission with AML-induction protocols, and recent advances in genetic profiling may enable the development of novel targeted therapies . Clinicians should maintain a high index of suspicion for MS in atypical head and neck masses.