H/O headaches and epistaxis.
There is evidence of an extra-axial mass lesion in the inferior frontal region. The lesion is hypointense with a few hyperintense areas within, on the T1W images. It is predominantly hyperintense on the T2W and FLAIR images. Multiple punctate and curvilinear hypointensities are seen within this lesion. After contrast administration the lesion shows heterogeneous but fairly intense enhancement, more so at it's periphery. It is seen to splay both the inferior frontal lobes and extend into the ethmoidal air cells, upper nasal cavity and frontal sinus on the right side. There is destruction of the cribriform plate of the ethmoid bone.
Esthesioneuroblastoma (olfactory neuroblastoma) is a slow growing malignant
neoplasm that originates from the olfactory neuroepithelium in the vicinity of
the cribriform plate. It usually occurs in the second and sixth decades of life.
Patients may present with nasal obstruction, episodic epistaxis,
hyposmia/anosmia, headaches and/or visual disturbances.
These lesions exhibit submucosal extension and invasion of the sinuses, orbits,
intracranial cavity and the brain.
Pathology:
On H/P they are seen as clusters of small round to ovoid cells with vascular septae and a neurofibrillary background.
On MRI:
Lesions are usually isointense to muscle and mucosa on the T1W images and heterogeneously hyperintense to muscle but hypointense to mucosa on the T2W images. Enhancement is minimal to moderate in all cases. T2W images help in differentiating sinonasal secretions from tumor. Edema in the inferior frontal lobes is highly suggestive of brain invasion.
The tumors also display a variety of imaging characteristics and aggressiveness. The expansile tendency of esthesioneuroblastomas is characterized by bowing of the sinus walls. The destructive aspect is manifested as tumor replacing the turbinates, septum, and sinus walls with extension into contiguous areas. Esthesioneuroblastoma should be suspected in all ages following identification of a mass in the superior nasal cavity demonstrating both expansile and destructive growth patterns. CSF spread and remote metastases may be seen in advanced cases.
CT usually provides the best information about the tumor and it's local invasion, especially into surrounding bony structures. MRI allows an estimate of tumor spread into surrounding soft-tissue areas, such as the anterior cranial fossa and the retro maxillary space.
Differential Diagnosis:
For a sinonasal mass with anterior skull base involvement:
Pediatric:
Lymphoma
Rhabdomyosarcoma
Carcinoma
Adults:
Squamous cell carcinoma
Lymphoma
Metastases
Meningioma
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