Inverted papilloma associated with esthesioneuroblastoma

Ill defined large lobulated solid lesion is seen within both nasal cavities (predominantly involving the right). There is distortion of normal turbinate anatomy within bilateral nasal cavity. The nasal septum is visualized in the midline. The lesion appears heterogeneously hyperintense signal on T2W and STIR images, which turns hypointense on T1W images with multiple areas of T1 W hyperintensity.  This represents internal hemorrhage / paramagnetic substance deposition.  On post contrast scan the lesion shows heterogeneous intense enhancement and central non enhancing components.

Laterally the lesion is extending into the both maxillary sinuses (more on right). There is pent up secretions within the bilateral maxillary sinuses.

Superiorly the lesion extends into the ethmoid air cells, fronto ethmoid recesses & frontal sinuses.  There is erosion & destruction of the lamina papayracea on right side with extension of lesion into right orbit extraconally, causing mass effect over the medial rectus muscle and adjacent orbital fat, however no definite involvement seen. There is thinning of left lamina papayracea with mass effect over orbital structure, however no definite intra orbital extension seen on left side.  The optic nerves are unremarkable. There is erosion and thinning of cribriform plate, however no obvious intracranial extension noted.

Posteriorly the lesion is extending upto the posterior choana & reaches upto the posterior naso-pharyngeal wall.  

Anteriorly there is lobulated soft tissue extension within the subcutaneous soft tissue near the orbital region.

Inflammatory changes are seen in sphenoid sinus.