**6. Conclusion**

REAHs and REAH-like lesions are relatively new clinical entities. Despite numerous publications they are still underdiagnosed. These lesions are located in the olfactory clefts. They can be isolated or in association with nasal polyposis typically in the case of recurrence after FESS.

The clinicians and pathologists must know these lesions. They are usually benign, but in some cases they are associated to frontal sinus blockage and widening of the nasal vault; loss of smell is common. The differential diagnosis includes diseases with more severe morbidities such as inverted papilloma, seromucinous hamartomas, and low-grade non-intestinal adenocarcinoma.

Histological examination of all the surgical specimens is necessary. The treatment is dictated by the disease.

The extent of the surgery depends on the type and size of the REAHs and the associated disease.

It consists of a limited polypectomy or a complete exenteration of the olfactory cleft associated or not to a full house ethmoidectomy and even a Draf III procedure.
