Importance of MRI in the diagnosis of a rare intracranial mucocele associated with frontal paranasal osteoma: Case report and literature review

Abstract

Osteomas and cystic mucoceles are well-known benign tumors, affecting the paranasal sinuses. However, the concomitant presence of both lesions represents a rare occurrence, with only a handful of reported cases. We report a case of a frontal sinus osteoma associated with an intracranial mucocele, in a 61-year-old male patient, with a 3-month history of intermittent headaches and subsequent generalized seizures. Post-contrast MRI showed a frontal heterogeneously enhanced lesion with an adjacent non-enhanced cyst. After surgical excision, histopathological examination established the diagnosis of osteoma with mucoid cyst. Mucoceles increase in size progressively and gradually. They are mostly asymptomatic, nevertheless, once they extend intracranially, complications like infections, seizures, or other neurological disturbances, may frequently occur, indicating the necessity for surgical treatment. Imaging modalities, in particular a head MRI is paramount while contemplating the differential diagnosis of a solid and cystic intracranial lesions, owing to its high sensitivity and specificity. The aim of this case report is to underscore the importance of considering intracranial mucoceles in the differential diagnosis of cystic lesions in the anterior cranial fossa when associated with a solid, possibly obstructing mass.

Diagnosis and Management of Craniofacial Osteomas

“…Osteomas of the skull base can lead to focal neurological motor deficits, headaches, 19,20,72,75 and global neurological dysfunction, including generalized seizures. 69,72 Exophthalmos can also arise from osteomas located in the orbital region. 76,77 On a more systemic level, large facial osteomas have been shown to present with fluctuating blood pressures, alterations of behavior, 78 forgetfulness, 78 and regressive hemiparesis 69 due to compression of brain parenchyma.…”

“…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.…”

“…Osteomas of the skull base can lead to focal neurological motor deficits, headaches, 19,20,72,75 and global neurological dysfunction, including generalized seizures 69,72 . Exophthalmos can also arise from osteomas located in the orbital region 76,77 .…”

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 ].…”