Unilateral Proptosis as the Initial Manifestation of Acute Myeloid Leukemia in a Young Adult.

A 22-year-old male presented with progressive unilateral proptosis, conjunctival chemosis, and vision loss in the right eye over the course of one month, without associated systemic symptoms such as fever, fatigue, or infections. Initial imaging, including CT and MRI, suggested benign orbital conditions like cavernous hemangioma or orbital pseudotumor. Despite the absence of systemic signs, hematological investigations revealed anemia, thrombocytopenia, and leukocytosis. A peripheral blood smear raised suspicion of a hematologic malignancy, which was confirmed by bone marrow biopsy, diagnosing acute myeloid leukemia (AML) with the t(8;21) translocation, a favorable cytogenetic subtype associated with AML with maturation. The patient was promptly started on induction chemotherapy with cytarabine and daunorubicin, resulting in a significant reduction of proptosis, improved extraocular movement, and partial restoration of vision. This case illustrates the unusual presentation of AML with initial ocular involvement, a rare but critical manifestation, and emphasizes the importance of considering hematological malignancies in young patients presenting with unexplained proptosis. Multidisciplinary collaboration led to a timely diagnosis and effective treatment. Early recognition and prompt initiation of chemotherapy are essential for both systemic remission and ocular recovery in such atypical cases.