Angiotropic

Because of its predilection for spread along vessel walls, mucor is sometimes called “angiotropic” Intracranial extension may occur due to this angiotropic spread or due to distal mycotic emboli or contiguous meningeal inflammation.[ 4 ] Thorough search of the literature revealed very few cases of diffusion-weighted MRI demonstration of optic ischemic neuropathy.[ 5 ] Out of these, MRI demonstrated ischemic optic nerve involvement due rhino-orbito-cerebral mucormycosis in only three case reports.[ 6 7 8 ] MRI findings confirming the infarction of the optic nerve are high signal intensity along the optic nerves on diffusion-weighted imaging, with corresponding low signal on apparent diffusion coefficient map with normal fluid-attenuated inversion recovery (FLAIR) and gadolinium-enhanced images.[ 6 7 ] These imaging findings and ensuing blindness may result from the invasion of the blood vessel walls by the organisms leading to occlusion or thrombosis of the central retinal artery or ophthalmic artery or direct optic nerve infiltration by mucormycosis.[ 6 9 ] Diffusion-weighted imaging is vital for early diagnosis of ischemic optic neuropathy and it shows the abnormality when other MR sequences are normal.[ 6 8 ] Various head and neck malignancies, such as adenoid cystic carcinoma, squamous cell carcinoma and lymphoma, are well known to spread in perineural fashion, the trigeminal nerve and its branches being the common site.[ 10 ] Perineural extension has been uncommonly reported in invasive mucormycosis.