Curious Case of a Medullary Lesion following Pontine Cavernoma Resection

• Main Authors: Perikal J Parichay, Kiran Khanapure, T J Aniruddha, J V Mahendra, Krishna C Joshi, Sunil V Furtado, A S Hegde
• Format: Article
• Language: English
• Published: ADICHUNCHANAGIRI INSTITUTE OF MEDICAL SCIENCES 2017-07-01
• Series: Journal of Medical Sciences and Health
• Subjects: hemiparesis; degeneration; post-surgery
• Online Access: http://www.jmsh.ac.in/index.php?option=com_k2&view=item&id=79:curious-case-of-a-medullary-lesion-following-pontine-cavernoma-resection&Itemid=79
• ISSN: 2394-9481; 2394-949X

The patient was evaluated with MRI brain which showed a hyperintensity in the left inferior olivary nucleus (ION). With a precedent history of brainstem surgery, a rare manifestation of pathology in the Guillain-Mollaret triangle causing HOD was ascertained. Figure 4 depicts the Guillain-Mollaret triangle and its connections.[1,2] With unilateral hypertrophy of ION, pathology is either in the red nucleus or the central tegmental tract (CTT). In this case, it is more likely the CTT on the left side is affected following the surgery Figure 4: Illustrative diagram of Guillain-Mollaret triangle of the left pontine lesion.[3] There is transsynaptic transneuronal degeneration of the left ION. This degeneration is unique as it causes hypertrophy of the ION rather than atrophy. Focal signal changes seen in the inferior medulla are not pathognomonic for HOD. Non-enhancement on contrast MRI differentiates it from other likely causes such as infarction, demyelinating disease, malignancy, infections, and inflammatory processes could also produce similar signal changes.[3,4] Symptomatic patients are difficult to treat and rarely resolve, but successful management of symptoms with benzodiazepines and carbamazepine has been reported.