Rare Presentation of Relapsed Acute Myeloid Leukemia Infiltrating Peripheral Nervous System: A Case Report

Acute monocytic leukemia is a subtype of acute myeloid leukemia (AML) characterized by aberrant proliferation and poor differentiation of monocytic cells and common tissue infiltration. Although very rare, AML can infiltrate peripheral nerves as an extramedullary presentation. In this case, a male patient in his 60s with a history of AML was admitted due to progressive neuropathic pain in bilateral upper extremities. Although the initial neurologic examination created a high clinical suspicion for Guillain-Barre syndrome, further testing showed an extramedullary relapse of AML with leukemia cutis and nerve and muscle invasion on a PET scan. This case highlights the unique propensity of monocytic AML to infiltrate tissue as well as the rarity of an extramedullary presentation and its associated challenges.