Aggressive giant pontine capillary telangiectasia with hypertrophic olivary degeneration and brainstem atrophy: illustrative case.

BACKGROUND

The clinical and radiological evolution of large capillary telangiectasias is largely unknown.

OBSERVATIONS: A 30-year-old female presented with progressive ataxia and nystagmus. She was found to have a large, diffuse enhancing pontomedullary lesion with associated hypointensity on susceptibility-weighted imaging consistent with a large capillary telangiectasia. In addition, she had a second capillary telangiectasia in the right frontal lobe, hypertrophic olivary degeneration (HOD), and multiple susceptibility lesions throughout the brain. The patient's condition continued to deteriorate and she became nonambulatory over 8 years, with right-sided hemiparesis and hemiataxia, nystagmus, palatal myoclonus, and a left abducens palsy. Over the follow-up period, serial MR images showed increased cavitation of the lesion and significant brainstem atrophy.

LESSONS: Capillary telangiectasias are generally small, benign lesions composed of dilated capillaries. However, when large (≥ 1 cm), they can be symptomatic. The authors present the case of a diffuse capillary telangiectasia of the pons with HOD and a progressively declining course due to brainstem atrophy and enlarging cavitation of the lesion. The radiological evolution of an aggressive capillary telangiectasia has not been previously reported. https://thejns.org/doi/10.3171/CASE24746.