Stable large enhancing subependymal nodule
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Patient with family history of tuberous sclerosis, mild mental retardation, affected child, and confirmed genetic test. Patient also had tuberous sclerosis in the kidney with an angiomyolipoma resected previously.
2002 MRI study showing subependymal nodule adjacent to foramen of Monro. Consistent with patient's history of tuberous sclerosis. A 1.2 x 0.9 x 1.3 cm subependymal nodule is noted in the right lateral ventricle.
1 case question available
2016 MRI study: Multiple cortical and subcortical tubers were noted (not shown), which are highly consistent with the patient's previous diagnosis of tuberous sclerosis.
Patient was reimaged to determine stability of lesion, presence or absence of obstructing hydrocephalus, and whether mass demonstrated characteristics of subependymal giant cell astrocytoma (SEGA).
Only 15% of patients with tuberous sclerosis have subependymal giant cell astrocytoma (SEGA), with the majority located at the foramen of Monro (Vézina).
In this case, there is a subependymal nodule in right lateral ventricle on the 2016 MRI that has remained unchanged compared to 2002 MRI. The patient was lost to follow-up for fifteen years. Importantly, this patient's subependymal nodule, which was located near the foramen of Monro, did not grow in the interval.
The differential here is between a large enhancing subependymal nodule and a subependymal giant cell astrocytoma. The location, size (larger than 1 cm) and background Tuberous Sclerosis might suggest that this is a subependymal giant cell astrocytoma. However, the lack of growth over 14 years makes this much less likely.
The stability of lesion and lack of obstructing hydrocephalus warrant no immediate treatment but continued imaging surveillance. In this case, follow-up MRI has been scheduled for twelve months.
Study dictated by Paul P. Pan, M.D. and presented by Rakesh Shah, M.D. Case courtesy of Paul P. Pan, M.D. and Rakesh Shah, M.D.