Objectives: The objective of this study was to determine the characteristics of medially originated inverted papilloma (MOIP) and compare them with laterally originated inverted papilloma (LOIP).
Methods: A retrospective review of the charts for a total of 83 patients with sinonasal inverted papilloma (IP) was conducted. Tumors originating from the nasal septum or the turbinates were categorized as MOIP, whereas tumors originating from the four sinuses were categorized as LOIP.
Results: Twenty-eight (34%) and 55 (66%) cases were categorized as MOIP and LOIP. MOIP from the middle turbinate behaved more aggressively than LOIP from the ethmoid sinus (P = 0.009), but less aggressively than LOIP from the maxillary medial wall (P < 0.05). Radical procedures were implemented in 14 patients with LOIP, but not in any patients with MOIP (P = 0.002). The recurrence rates were comparable in both groups (P = 0.472).
Conclusions: The categorization of IP on the basis of tumor origin enabled a better surgical design and more accurate excision of the tumor. Although in some cases MOIP may behave more aggressively, radical procedures were indicated in only the late Krouse stage LOIP without compromising the recurrence rate.