Cavernous malformations (cavernomas) are rare vascular anomalies characterized by clusters of abnormally dilated capillary-like vessels, prone to repeated hemorrhages due to their fragile endothelial lining. Cavernous malformations may be sporadic or familial with autosomal dominant inheritance involving mutations in CCM1 (KRIT1), CCM2, or CCM3 (PDCD10) genes.1 Cavernomas predominantly involve the central nervous system, where their proximity to critical neural pathways can result in significant neurological deficits. Approximately 20%–35% of cerebral cavernous malformations are located in the brainstem. Brainstem cavernomas are prone to symptomatic hemorrhage, and even minor bleeds may produce significant neurological deficits.2 Isolated sixth nerve palsy is rare and can occur due to intralesional hemorrhage or local mass effect from a pontine cavernoma along the intra pontine course of the abducens nerve. We report a case illustrating this rare presentation. A 36-year-old female presented with headache persisting for 3 days, followed by the sudden onset of binocular double vision. Ophthalmic evaluation showed 15° esotropia of the left eye on Hirschberg’s test, with a −4 limitation of abduction Fig. 1. Diplopia charting demonstrated uncrossed horizontal separation of images Fig. 2, which increased in the left gaze. Neuroimaging: MRI Figs. 3 and 4 of the brain and orbits with contrast revealed a focal lesion with intralesional hemorrhage located in the dorsal aspect of the left hemipons, consistent with a cavernous malformation. Given the neurological involvement, the patient was referred to a neurologist for further evaluation and management. Prognostic factors such as initial neurological status, lesion accessibility, and recurrent hemorrhage significantly influence treatment decisions.3 Cavernous malformations are managed conservatively in stable cases, while surgical resection is reserved for symptomatic hemorrhage or progressive neurological decline. Early neuroimaging is recommended in young patients presenting with cranial nerve palsies to identify rare but potentially serious brainstem pathologies such as cavernomas.Figure 1: 9 Gaze picture showing 15 degree esotropia in the primary gaze and limitation of abduction in the left eyeFigure 2: Schematic diplopia chart showing binocular horizontal diplopia with maximal separation in the left gaze, consistent with left lateral rectus palsyFigure 3: MRI brain and orbit – Axial T2-weighted MRI showing a lesion with scattered intralesional T2 hypointense foci, suggestive of internal hemorrhagic component (arrow)Figure 4: MRI brain and orbit – Axial susceptibility-weighted imaging (SWI) of the brain demonstrating a focal area of signal drop-out (blooming) in the dorsal aspect of the left hemipons (arrow), suggestive of intralesional hemorrhageAuthors’ contributions Shivam Goyal: Clinical studies, data acquisition, manuscript preparation, manuscript editing, manuscript review. Virna Shah: Concept, design, manuscript review. Nivetha R.: Definition of intellectual content, clinical studies, manuscript review. All authors have read and approved the manuscript. Each author certifies that this submission represents original and honest work. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.
Goyal et al. (Wed,) studied this question.