Severe complication after administration of formalin for treatment of progressive ethmoidal hematoma in a horse

Large progressive ethmoidal hematomas can deform normal soft and osseous tissues of the head. Treatment of the lesion with formalin can result in severe complications if the cribriform plate is fenestrated by the chronic presence of a large progressive ethmoidal hematoma. Three-dimensional imaging is recommended before formalin treatment of large progressive ethmoidal hematomas to determine the extent of the lesion and local destruction of normal tissues.