A Lateral Neck Myeloid Sarcoma Presenting as Acute Otitis Externa

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Myeloid sarcoma (MS) is an extramedullary tumor of myeloid cells, often associated with acute leukemia.
• Diagnosis requires pathological and immunohistochemical evaluation due to varied presentations.
• Isolated extramedullary relapse (iEMR) after allogeneic stem cell transplantation (allo-SCT) is rare and may not involve bone marrow.

Observation:

• This case report details a patient with a history of acute myeloid leukemia (AML) who underwent allo-SCT.
• The patient presented with a left lateral neck mass mimicking acute otitis externa.
• The mass was diagnosed as an isolated myeloid sarcoma.

Findings:

• Myeloid sarcoma can occur as an isolated extramedullary relapse post-allo-SCT, independent of bone marrow involvement.
• Leukemic cells can persist in extramedullary sites despite systemic therapy and graft-versus-leukemia effects.
• Accurate diagnosis relies on pathology and immunohistochemistry.

Implications:

• MS should be considered in patients with a history of acute leukemia, even with infectious-like symptoms.
• Timely diagnosis of iEMR is critical for patient survival.
• Combined therapeutic strategies (systemic, local, cellular) are recommended for managing iEMR post-allo-SCT.