Esthesioneuroblastoma (Olfactory neuroblastoma)

Findings

Large enhancing mass with epicenter at the level of the cribriform plate with postobstructive non-inflammatory mucosal disease. Mass invades left orbit, anterior ethmoidal air cells, medial aspect of the left maxillary sinus and frontal sinuses bilaterally. Intracranial, extradural extension with bifrontal mass effect and moderate dural enhancement. Edema or infiltration of the subcutaneous soft tissues of the frontal scalp.

Differential diagnosis:
- Esthesioneuroblastoma
- Squamous cell carcinoma of the nasal cavity
- Lymphoma
- Ewing sarcoma
- Embryonal rhabdomyosarcoma


Diagnosis: Esthesioneuroblastoma (Olfactory neuroblastoma)


Key points

Rare, highly malignant tumors composed of small round cells encircled by vascularized connective tissue.
Usually occurs in young men with second occurrence peak at ~50-60 years.
Most commonly arise superolaterally in the nasal cavity (between the middle turbinate and cribriform plate) from neuroendocrine cells within the olfactory mucosa.
Locally invasive within the nasal cavity and paranasal sinuses with frequent intraorbital and intracranial extension (squamous cell carcinoma and lymphoma often demonstrate less aggressive pattern of bony destruction).
Non-inflammatory sinusitis often accompanies disease due to obstruction.
Distant metastases in approximately 20% of cases.


Radiology

MRI:
- Hypointense to brain on T1-weighted images.
- Hyperintense to brain on T2-weighted images.
- Heavily T2-weighted images help to differentiate mass from associated obstructed sinus secretions, which usually appear brighter than the tumor.

CT: Enhancing mass with associated bony expansion and destruction.