MYSTERY CASE RESPONSES

The Mystery Case series was initiated by the Neurology® Resident & Fellow Section to develop the clinical reasoning skills of trainees. Residency programs, medical student preceptors, and individuals were invited to use this Mystery Case as an educational tool. Responses were solicited through a group e-mail sent to the American Academy of Neurology Consortium of Neurology Residents and Fellows and through social media. All the answers that we received came through social media, from individuals rather than groups. Most of the respondents (61%) indicated a putative diagnosis of tuberous sclerosis (TS) as the most likely etiology. Other considerations included focal cortical dysplasia, as well as demyelinating or infectious processes. The most complete answer came from Dr. Pedro Serrano Castro (Spain). In his response, he pointed out that the left parietal cortex is dysplastic and that the cutaneous lesions are suggestive of mTOR pathway dysfunction as seen in CS.

The cortical and subcortical tubers seen in TS have a different appearance on brain MRI with a low T1 and a high T2/fluid-attenuated inversion recovery signal. Other MRI diagnostic criteria for TS include the presence of subependymal nodules, subependymal giant cell astrocytomas, and cerebral white matter migration lines.

This Mystery Case illustrates the rare finding of a focal cortical dysplasia in a patient with CS.

Dragos A. Nita, MD, PhD

The Hospital for Sick Children, University of Toronto, Canada.