Hemorrhagic hereditary telangiectasia (HHT)

Case contributed by Frank Gaillard
Diagnosis certain

Presentation

Seizure

Patient Data

Age: 40 years
Gender: Male

Initial non-contrast examination demonstrates a small cluster of serpiginous mildly hyperdense structure is in the right frontal lobe superiorly. There is a small region of surrounding gliosis. No acute hemorrhage. Remainder of the brain has normal appearances. No hydrocephalus.

CT angiogram Circle of Willis - Arterial phase contrast enhanced scans from arch to vertex demonstrates a bovine configuration of the aortic arch.The common and internal carotid arteries and vertebral arteries in the neck are normal. No intracranial stenosis or occlusion.

Nidus of tortuous vessels in the right superior frontal sulcus measures approximately 11 mm, supplied from a branch of the right anterior cerebral artery and draining to the superior sagittal sinus. There are at least 2 rounded enhancing structures lurched of the nidus which may represent intra nidal aneurysms or (more likely) venous varices. Note made of hypoplastic right A1 segment and large anterior communicating artery. A 2.8 centimeter pulmonary arteriovenous malformation is identified in the right upper lobe. There is mild surrounding groundglass opacity.

Conclusion: Small right frontal arteriovenous malformation with either intranidal aneurysm or varix but no evidence of deep drainage. No evidence of recent bleed. Presence of a right apical pulmonary AVM suggests underlying hereditary hemorrhagic telangiectasia (HHT).

A well defined arteriovenous malformation is demonstrated within the apical segment of the right upper lobe. Two enlarged vessels are seen entering the malformation, presumably the artery and vein feeding artery. There is mild surrounding ground-glass opacity.

Small 3 mm calcified nodule adjacent to the right horizontal fissure, likely granuloma. 

Small cluster of serpiginous flow voids is seen in the right superior frontal gyrus. Limited MRA confirms a nidus of tortuous vessels derived from an incompletely imaged arterial feeder (which on CTA was seen to arise from the right anterior cerebral artery). There is a minimal surrounding FLAIR hyperintensity consistent with gliosis but no evidence of hemorrhage. No mass effect is demonstrated.

There are multiple (three) punctate foci of diffusion restriction in the cortex of the left superior frontal lobe, left occipital lobe and left parietal lobe. Old left thalamic lacunar infarct. No other signal abnormality identified. Mega cisterna magna is incidentally noted.

Conclusion: Right frontal arteriovenous malformation with no evidence of hemorrhage. Given the co-existence of a pulmonary arteriovenous malformation, hereditary hemorrhagic telangiectasia is the likely underlying etiology as previously stated.

Three punctate foci of diffusion restriction in the left cerebral hemisphere are consistent with acute ischemia. These are most likely embolic, with the pulmonary arteriovenous malformation a possible cause of paradoxical embolism.

Small red lesions on the tongue and lip are typical of oral cavity telangiectasias. 

Case Discussion

Right frontal cerebral arteriovenous malformation (AVM) in the setting of associated apical pulmonary AVM and mucosal changes are characteristic of underlying hereditary hemorrhagic telangiectasia (a.k.a. Osler–Weber–Rendu disease), which was subsequently confirmed. 

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