Intradural extension of mucocele secondary to giant frontal sinus osteoma: Diagnostic pitfalls

Abstract

Background: Paranasal sinus osteoma in association with intracranial mucocele is a rare entity while intradural extension is even rarer. Our aim of presenting this case is to highlight the diagnostic pitfalls and reiterate the importance of prompt treatment of expected complications. Case Description: A 35-year-old known epileptic, for the past 5 years, presented with altered sensorium for the past 2 days. Computed tomography (CT) of the brain plain showed ventriculomegaly and cystic lesion in the left frontal lobe adjacent to a calvarial osteoma. A ventriculoperitoneal (VP) shunt was done which resulted in tension pneumocephalus and led us to discover the origin of osteoma from the left frontal sinus on CT functional endoscopic sinus surgery (FESS) protocol. He underwent left frontal craniotomy. The osteoma and mucocele were excised completely and watertight primary dural closure was done. Postoperative meningitis was treated with antibiotics according to the culture report. Conclusion: Intracranial extension of mucocele led to meningitic hydrocephalus, prompting us for VP shunt. Resulting tension pneumocephalus revealed what was missed on preop CT, a small pocket of air adjacent to osteoma intracranially. Therefore, this case underscores the importance of obtaining a preoperative CT FESS to elaborate the origin of osteoma, thus planning approach differently.

Diagnosis and Management of Craniofacial Osteomas

“…The most common location for an osteoma to arise in the paranasal sinuses is the frontal sinus, which accounts for over 80% of paranasal sinus osteomas. 53,66 Due to interruption of mucus outflow, osteomas can present similarly to sinus infections with rhinosinusitis, 67,68 headache, 69 epistaxis, 70 parosmia, 71 facial swelling, 24,72,73 transient motor aphasia of the facial musculature, 69 nasal obstruction, and pain. 19,74 If untreated, obstructed sinuses can progress to abscess formation within the region of impaired outflow.…”

Craniofacial Osteomas: From Diagnosis to Therapy

“… Author N° Ref. Patient Gender Patient Age Osteoma Localization Clinic Imaging Comorbidity Ortega Beltrá [ 19 ] M 68 Mandibula Ankylosis of the temporomandibular joint CT No Alkhaldi [ 20 ] M 44 Ethmoid sinus, orbital cavity, ostium of the maxillary sinus Chronic rhinosinusitis CT Prior endoscopic sinus surgery Dedushi [ 21 ] M 61 Frontal sinus Headaches, generalized seizures, transient motor aphasia, regressive hemiparesis, and fluctuating blood pressure values MRI No Ali [ 22 ] M 35 Frontal sinus Altered Sensorium CT, MRI No Mlouka [ ...…”

“…As an osteoma is a dense bone lesion, its evaluation is faster and more effective via CT [ 57 ]. Nevertheless, MRI can be used as a supplement to CT in the assessment of adjacent soft tissues and complications associated with an osteoma, such as inflammatory changes in mucosa in the case of an osteoma arising in paranasal sinuses [ 21 , 22 , 25 , 28 , 31 , 35 , 37 ].…”