No significant immunohistochemical differences exist between preretinal tissues taken from myopic traction maculopathy (MTM) patients and patients with idiopathic epiretinal membranes, according to findings published in Retina. In MTM, the formation of outer retinal schisis-like changes and neurosensory retinal detachment is likely due to axial elongation and preretinal traction, not a uniquely abnormal cellular process according to the report.
MTM is now used to describe the condition known as myopic foveoschisis or myopic macular schisis. Despite being present in up to 34% of patients with high myopia with staphylomas, MTM’s pathophysiology is unclear. To learn more, researchers in Miami studied preretinal tissue specimens from eyes with MTM removed during pars plana vitrectomy and a control group of 6 idiopathic epiretinal membranes for comparison.
They found that outer retinal schisis-like thickening was present in 100% of preoperative optical coherence tomography (OCT) images, and 4 of the 6 eyes had subfoveal neurosensory retinal detachment. Postoperative OCT images demonstrated complete resolution of the schisis-like appearance in all eyes, and a full-thickness macular hole occurred in 2 of the 6 eyes.
Histopathologic examination revealed fibrocellular tissue that was strongly positive for glial fibrillary acidic protein, weak to moderately positive for cytokeratin, and weakly positive for smooth muscle actin and CD68. The researchers noted no apparent histopathologic or immunohistochemical differences between preretinal tissues from eyes with MTM and idiopathic epiretinal membranes from control eyes.
“Because the cellular composition of [preretinal tissues] in MTM is histopathologically similar to PRTs in idiopathic [epiretinal membrane] cases, we propose, therefore, that the predominant mechanism in the development of MTM is cellular contraction, perhaps exacerbated by axial elongation and persistent vitreomacular attachment, rather than a unique cellular milieu,” the study says.
Russell JF, Naranjo A, Dubovy SR, et al. Clinicopathologic correlation of preretinal tissues in myopic traction maculopathy. Retina. 2021;41(7):1512-1517. doi:10.1097/IAE.0000000000003045