Rome: Roma defender Leandro Castan will undergo neurosurgery next month after complaining of dizziness during a Serie A match.
Castan, 28, has been sidelined since the second game of the season, a 1-0 win away to Empoli in September.
Tests revealed the Brazilian suffers from "a congenital vascular alteration in his brain, a condition more commonly known as a cavernoma", according to a club statement.
Roma added: "Inside the cavernoma, the tests revealed a small edema and, as a consequence, temporary swelling.
"This was the cause of the symptoms reported by the player, which subsided of their own accord within a few days."
Roma said because Castan is "at risk of reoccurrences", it has been decided he will "undergo neurosurgery at the beginning of December in order to definitively cure the problem".
"This will allow him to resume regular competitive sporting activity."
Roma sit second in Serie A three points behind leaders and champions Juventus.