A 16-year-old male presented with recurrent nasal bleeding. Imaging revealed a large mass along the left nasal fossa with lobulated contours and extension into multiple compartments including the nasal cavity, sinuses, and intracranial space. The mass showed intermediate signal intensity on T2-weighted imaging with a macrocyst along the periphery of the intracranial component. These features are characteristic of an olfactory neuroblastoma, also known as esthesioneuroblastoma, which arises from the olfactory epithelium and commonly involves multiple nasal compartments with cyst formation along the intracranial periphery.

2. Macrocyst along the periphery of the intracranial component of the lesion.

3. Interspread haemorrhage , microcysts in the core of the lesion.

4. Epicentre along the left nasal fossa with more of the longitudinal than horizontal extension. MERCURY IMAGING INSTITUTE SCO 172-173 SEC 9C CHANDIGARH MERCURY IMAGING CENTRE SCO 16-17 SEC 20D CHANDIGARH

5. Esthesioblastoma a brief.............. Esthesioneuroblastomas are histologically similar to adrenal or sympathetic ganglionicneuroblastomas and retinoblastomas. Originally descried by Bergen et al. in 1924 as esthesioneuroepitheliomaolfactif . Incidence peaks once in 11-20 years of age group and again in 50-60 years age group :However, age of these patients ranges from 3-88 years. It occurs equally in men and women. Synonyms include olfactory esthesioneuroma, neuroesthesioma and olfactory neurocystoma.

7. Nasopharyngeal carcinoma.

8. Pitutarymacroadenoma

10. T2w SEQUENCE – large macrocyst with intermediate signal core contents in the intracranial part of the Mass . Multicompartmentinvolvement extending from the nasal cavity to sinuses to intracranial compartment. ESTHESIONEUROBLASTOMAIS ALMOST ALWAYS UNILATERAL . ONLY NEGLECTED CASES MAY PRESENT AS BILATERAL NASAL FOSSA MASSES.

11. T2w sequence – Macrocyst with variegated intermediate signal core contents . Appreciate the buckling of the adjacent brain parenchyma

12. No inversion of the cystic component of the mass lesion on FLAIR sequence.

13. SAGITTAL PLANE

14. INTERMEDIATE TO HYPERINTENSE SIGNAL ON t1w SEQUENCE No inversion of the core contents on the fat sat sequence.

15. No pathological restriction of diffusion . Interspread bloom on GRE sequence suggestive of haemorrhage / calcification

16. Points of interest.................. Multicompartment involvement. Usually unilateral lesion. Longitudinal pattern of extension. Macro/ microcysts along the periphery of the intracranial part of the lesion.