BMJ Case Reports: first published as 10.1136/bcr-2012-008273 on 7 February 2013. Downloaded from Images in… Hypothalamic Reuben Grech, Seamus Looby, John Thornton, Paul Brennan

Department of Neuroradiology, DESCRIPTION Beaumont Hospital, Dublin, A 9-year-old girl presented with an 8-month Ireland history of gelastic seizures and . Correspondence to Clinical evaluation including full neurological Dr Reuben Grech, assessment was otherwise unremarkable. Endocrine [email protected] tests were normal and there was no family or surgi- cal history of note. Hypothalamic or hamartoma is a rare non-neoplastic heterotrophic lesion, which forms part of the spectrum of grey matter heteroto- pias. It is composed of a disorganised mass of neur- onal cells within the tuber cinereum of the Figure 2 The lesion (arrows) also appears isointense on . It may occur either as a sessile or as coronal (A) and axial (B) T2-weighted images. It lies a pedunculated lesion. centrally within the suprasellar cistern and is just Presentation occurs in the first decade and mani- posterior to the (arrowhead). fests with isosexual precocious puberty owing to luteinising hormone releasing hormone secretion, gelastic seizures, hyperactivity, visual deficits and ant for radiological diagnosis and distinguishes the neurodevelopmental delay. Gelastic seizures are tumour from commoner regional pathologies characterised by uncontrollable bursts of laughter including hypothalamic , germ cell lasting between 2 and 30 s, and affected children tumours and Langerhans cell histiocytosis.2 may rarely enter into ‘status gelasticus’.1 Treatment with luteinising hormone receptor Hypothalamic are typically isolated agonists is often effective with surgery being lesions but may also occur in the setting of reserved for refractory cases. Pallister-Hall syndrome. They are seen as well-defined round masses on imaging, which measure up to 4 cm in diameter Learning points and project inferiorly into the suprasellar or inter- peduncular cisterns. The hamartoma is isodense on ▸ http://casereports.bmj.com/ CT and follows grey matter signal on both Gelastic seizures are short epileptic events T1-weighted (figure 1) and T2-weighted sequences characterised by bouts of laughter and are (figure 2). Lack of contrast enhancement is import- classically associated with hypothalamic hamartomas. ▸ Hypothalamic hamartomas are isodense on CT, follow grey matter signal on MRI and do not enhance. ▸ Differential diagnoses include hypothalamic astrocytomas, germ cell tumours and Langerhans cell histiocytosis. on 27 September 2021 by guest. Protected copyright.

Competing interests None. Patient consent Obtained. Provenance and peer review Not commissioned; externally peer Figure 1 Coronal (A) and sagittal (B) reviewed. contrast-enhanced T1-weighted sequences show a pedunculated lesion (arrows) arising from the floor of the REFERENCES and projecting into the suprasellar cistern. 1 Striano S, Santulli L, Ianniciello M, et al. The gelastic It is isointense to grey matter, does not enhance with seizures-hypothalamic hamartoma syndrome: facts, hypotheses, contrast and lies between the pituitary stalk and the and perspectives. Behav 2012;24:7–13. mammillary bodies. The imaging features are compatible 2 Dähnert W. Radiology review manual/Wolfgang Danert. with a hypothalamic hamartoma. Philadelphia: Lippincott Williams Wilkins, c2007; 2007.

To cite: Grech R, Looby S, Thornton J, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2012- 008273

Grech R, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2012-008273 1 BMJ Case Reports: first published as 10.1136/bcr-2012-008273 on 7 February 2013. Downloaded from Images in…

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2 Grech R, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2012-008273