Congenital hydrocephalus in a stillborn Marwari foal: Dystocia management and histopathological characterisation

Summary Congenital hydrocephalus, a rare condition in Marwari foals, is characterised by excessive accumulation of cerebrospinal fluid within the cranial cavity. A full‐term pregnant mare with two fetal limbs protruding from the vulva was presented. Vaginal examination revealed an enlarged, soft fetal poll region with non‐fused frontal bones. Decompression of the fetal cranium using a Robert's knife led to the evacuation of fluid and subsequent collapse of the fetal head, facilitating delivery of a stillborn male foal through gentle traction. The post‐delivery postmortem examination and histopathology were performed, and grossly, the foal exhibited a markedly enlarged cranial cavity with a thin, membranous brain, confirming hydrocephalus. Histopathological examination revealed meningeal oedema, dilated blood vessels, cortical atrophy with glial cell aggregation and fibrin thrombi within vessels. The cerebellum showed areas of malacia, loss of Purkinje cells and thickening of the Cajal–Retzius layer. This report documents a rare case of dystocia in a mare caused by congenital hydrocephalus in a foal, along with detailed histopathological characterisation of the brain.