Location and appearances are typical of olfactory neuroblastoma, which was proven histologically. Differential to consider would be a sinonasal carcinoma and meningioma/hemangiopericytoma.
Some relevant aspects of olfactory neuroblastoma:
- peaks in young adult patients (~2nd decade) and another peak in the 5th to 6th decades
- nasal stuffiness and rhinorrhea or epistaxis are also referred as primary symptoms
- arises from the basal layer of the olfactory epithelium in the superior recess of the nasal cavity
- slow-growing tumor
- tends to destroy surrounding bone, and can extend in any direction
- on imaging, they usually present as a soft tissue mass in the superior olfactory recess involving the anterior and middle ethmoid air cells on one side and extending through the cribriform plate into the anterior cranial fossa
- contrast enhancement is often marked in both CT and MRI studies
- treatment usually involves combined chemotherapy and/or radiotherapy with surgical excision
- prognosis is significantly affected by the presence of distant metastases