Atypical Association of Ethmoidal Encephalocele and Hydrocephalus in an Adult Patient with Autosomal-Dominant Osteopetrosis Type I (ADO-I): A Case Report

BACKGROUND: Osteopetroses are a heterogeneous group of heritable disorders characterized by increased bone density as the result of defective osteoclast-mediated bone resorption. The autosomal-dominant osteopetrosis type I (ADO-I) is defined by the presence of osteosclerosis involving mainly the skull bones, variably associated with compression of the foramina of cranial nerves and vascular structures, hypertelorism, exophthalmos, and less commonly with hydrocephalus, pseudotumor, and Chiari malformation type I. CASE DESCRIPTION: We describe an adult patient with ADO-I presenting with an atypical association of clinical manifestations that required a tailored management. On admission, the patient complained about chronic headache, recurrent sinusitis, and postnasal drip. Findings of the examination didn't show clear signs of increased intracranial pressure, whereas imaging studies revealed thickening of the skull bones and an unexpected fistula associated with anterior ethmoidal meningoencephalocele. Some days after endoscopic transnasal closure of the fistula, a severe hypertensive hydrocephalus developed, which required a prompt ventriculoperitoneal shunt placement, complicated by a diffuse subarachnoid hemorrhage. The 6-month follow-up showed complete recovery. CONCLUSIONS: After reviewing the literature, we can confirm that ours was the second case of an adult ADO-I patient associated with anterior ethmoidal meningoencephalocele, the first one needing a combined treatment of the encephalocele and hydrocephalus. Because ADO-I is a rare disease with a wide spectrum of clinical manifestations, our case can represent a prototype for the future management of similar cases.