Methylene Blue “Avatar” Brain

Abstract

Methylene blue is a safe and effective therapeutic agent used in a variety of different clinical settings, including as treatment for methemoglobinemia, reversing ifosfamide-induced encephalopathy, severe hepatopulmonary syndrome, and as a pressor during catecholamine-refractory septic shock (1). Of more relevance to neuropathologists, it has recently been experimentally tested as a dye in multimodal confocal imaging of brain tumors for intraoperative detection of brain tumors (2), for ischemic/reperfusion injury (3), and, because it seems to prevent aggregation of tau and β-amyloid, as a potential therapeutic agent for neurodegenerative disorders such as Alzheimer disease (4) and Huntington disease (5, 6). As such, neuropathologists may encounter patients at autopsy treated with methylene blue. Methylene blue generates a clinically innocuous, self-limiting, but striking blue-green discoloration to the urine, skin, and mucosa of treated individuals as a by-product of its use (1, 7, 8). This systemic tissue discoloration is more well known than is discoloration of brain tissues, which, to our knowledge, has only been reported once previously (9). The tissues were reported to transform into a bright blue-green color when the colorless leukomethylene blue molecule undergoes oxidation to methylene blue on exposure to air (9). We share our recent experience with brain tissue discoloration and methylene blue use, capturing the transition from colorless to colorful during a very short time interval at the time of autopsy. A 20-year-old woman with asthma and surgically repaired coarctation …