A 24-year-old man, previously healthy, presented to the hospital emergency in February 2021, complaining of pain in the back region radiating to the flanks and hips for 12 days. He had previously sought care on three occasions, without relief with anti-inflammatory drugs. On admission, his physical examination was normal, and laboratory tests showed 23900 leukocytosis and 70% blasts, no anemia or thrombocytopenia, normal renal and liver function tests, and negative serologies. Chest radiography and ultrasound of the abdomen plus urinary tract showed no particularities. Immunophenotyping was requested, which diagnosed maturation acute myeloid leukemia; the patient was hospitalized for therapy. He still complained of intermittent pain crises in the lumbar region, evolving with bladder dysfunction, weakness, and paresthesia in both lower limbs. Upon starting protocol with Cytarabine + Daunorubicin on the fourth day of hospitalization, the man evolved with proprioceptive loss and paraplegia of the lower limbs. Urgent magnetic resonance was requested, showing an expansive formation in the posterior epidural space at the level of T9-T11, suggestive of granulocytic sarcoma. Lesion biopsy was not performed. A course of dexamethasone was carried out and a response to chemotherapy was observed; the patient had a partial return of strength in both lower limbs and completed the systemic treatment.

Acute myeloid leukemia (AML) is the most prevalent acute leukemia in adults, representing about 1% of all neoplasms, 10% of which are of the subtype called AML with maturation. This is the subtype most associated with granulocytic sarcoma, also called chloroma. Granulocytic sarcoma is a solid tumor of granulocyte precursor cells located in various extramedullary sites, which can cause a copious constellation of symptoms. In this case, MRI showed a highly suspicious lesion for infiltrative chloroma in the CNS, causing a medullary compression syndrome with serious clinical repercussions. In other tissues, local management of the tumor can be performed with surgical resection or radiotherapy, which were unfeasible therapeutic options for the case presented.

Although rare, granulocytic sarcoma should be considered a differential diagnosis in patients with acute leukemia, who present with compressive symptoms. In some cases, it may represent a hematological urgency, even before the primary neoplasm diagnosis, and its correct management is essential in such situations.