Atypical Localization and Clinical Presentation of a Hypothalamic Hamartoma in an Adult with Epilepsy
A B S T R A C T
Epilepsy in patients with Hypothalamic hamartomas (HH) have a typical semiology (gelastic or dacrystic seizures), but there is also secondary epileptogenesis that can explain why some of them have “pseudotemporal” seizures. We present a case report of an atypical localization and clinical presentation of HH in an adult with a rare presentation of secondary epileptogenesis.
Keywords
Hypothalamic hamartoma, focal epilepsy, temporal lobe epilepsy, secondary epileptogenesis
Introduction
Hypothalamic hamartomas (HH) are non-neoplastic heterotopic tissues which contains normal neurons and glia including oligodendrocytes and fibrillary astrocytes but in an abnormal distribution. Even though they are rare and don't have a neoplastic evolution, they grow as fast as the tissue around them [1]. Munari et al., have already demonstrated with stereoEEG studies the role of the HH in generating seizure activity [2]. “Epileptic” HH are usually sessile and closely connected to the mammillary bodies [3]. The epilepsy syndrome noted in adult patients with HH appears to be different from the catastrophic epilepsy noted in children. The epilepsy syndrome is usually restricted to one or two focal seizure types, commonly focal onset with impaired consciousness (“pseudotemporal”) seizures, or tonic seizures, with a variable expression of gelastic seizures (less frequent than in children), and occasional generalized seizures. Also, learning difficulties and behavioural problems are less frequent [4]. In this case report, we present a patient with focal onset and impaired consciousness seizures and a HH originating in the left mammillary body.
Case Report
A 45-year-old, right handed, male patient, with a history of thyroid dysfunction, initiates at the age of 36, with focal with impaired consciousness seizures characterized as unresponsive period with oral and bilateral hand automatisms, especially during sleep. His seizure frequency was variable, from daily to weekly. Interictal EEG showed left temporal anterior spikes and sharp waves. Ictal EEG showed late left anterior temporal slow activity in alfa/theta range (Figure 1). In the magnetic resonance imaging (MRI) we observed a sub-centimetric nodular expansion of the left mamillary body, with isointense signal in respect to the contralateral, suggestive of hamartoma. It was isointense to the gray matter on T1- and T2-weighted (W) imaging and showed no enhancement on post gadolinium T1W series (Figure 2). DTI sequences revealed an asymmetric anisotropy fraction in both temporal lobes, being smaller in the left side. The patient did not develop cognitive dysfunction, behavioural problems or gelastic seizures. He received medical treatment with LEV, BRV, VPA, LCM without clinical response.
Figure 1: A) Interictal EEG: Left anterior temporal spikes and sharp waves. B) Ictal EEG: Alfa/theta range slowing in left anterior temporal area.
Figure 2: A) Coronal; B) Sagital; C) Axial three-Dimensional T1-weighted images fast spoiled gradient echo (FSPGR) (TR/TE= 9/3) shows a sub-centimetric nodular expansion of the left mamillary body, with isointense signal with respect to the contralateral, suggestive of hamartoma (arrows in A, B and C).
Discussion
Mammillary tract is an unusual localization of HH. Although there is evidence of the intrinsic epileptogenicity of the HH´s, we usually see typical clinical presentations with gelastic or dacrystic seizures, in the majority of these patients [2]. In a series of 5 patients, Kahane et al. studied with stereoEEG HH´s with refractory epilepsy and he proposed whether 4 of them had interictal and ictal discharges coming from HH´s, there was another type of seizures in which the HH wasn't involved. So, he proposed a theory of secondary epileptogenesis in which through the mammillary tract -Thalamus-cingulate gyrus, it can reach the cortex [5]. But these kinds of seizures were late in the evolution of epilepsy and they were happening at the same time as gelastic seizures. So, in our case we present a patient who only have clinically pseudo temporal lobe seizures and in EEG we can see interictal discharges in left temporal lobe and an ictal EEG which does not show a clear localization but we can see some late slow waves in the left hemisphere. As Kahane et al. described, the secondary epileptogenesis, if present, tends to be on the same side of the HH. So, we think this is an atypical presentation of an HH with secondary epileptogenesis.
Conflicts of Interest
None.
Article Info
Article Type
Case ReportPublication history
Received: Mon 17, Jan 2022Accepted: Sat 29, Jan 2022
Published: Mon 21, Feb 2022
Copyright
© 2023 Marone Abril Maria. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hosting by Science Repository.DOI: 10.31487/j.SCR.2022.01.06
Figures & Tables
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