Doughnut sign (orbit)
Citation, DOI & article data
The doughnut sign of optic nerve sheath meningioma refers to the appearance of this tumor on coronal CT/MRI. The meningioma forms a thick cuff of enhancing tumor around the central non-enhancing optic nerve, mimicking the appearance of a ring doughnut. It is the coronal equivalent of the tram-track sign.
Neither the tram-track sign, nor - by extension - the doughnut sign appearance of the optic nerve, are by any means pathognomonic 2.
Other described causes of this sign include 2,3:
- demyelinating optic neuritis
- idiopathic orbital inflammation
- perioptic hematoma
- Erdheim–Chester disease
- leukemic infiltration of the optic nerve
- leptomeningeal metastases to the optic nerve 2
History and etymology
The doughnut sign of optic nerve sheath meningioma was first described, on CT, in 1983 1.
- 1. Peyster RG, Hoover ED, Hershey BL, Haskin ME. High-resolution CT of lesions of the optic nerve. (1983) AJR. American journal of roentgenology. 140 (5): 869-74. doi:10.2214/ajr.140.5.869 - Pubmed
- 2. Nair AG, Iyer VR, Gopinathan I. Revisiting the "Tram-Track" sign. (2017) Indian journal of ophthalmology. 65 (11): 1217-1218. doi:10.4103/ijo.IJO_510_17 - Pubmed
- 3. Johns TT, Citrin CM, Black J, Sherman JL. CT evaluation of perineural orbital lesions: evaluation of the "tram-track" sign. (1984) AJNR. American journal of neuroradiology. 5 (5): 587-90. Pubmed