Table 3.

General location for IP malignant transformation surveillance

Study authors	Year	Study design	Level of evidence	Study groups	Intervention	Outcome	Conclusion
Lin et al. [14]	2014	Observational study	C	129 patients, 19 SCC (14.7%)	Medical history reviewed.	IP requires follow up of more than 2 years. 5 year survival for IP with SCC is 61%. No clear predictors of malignancy were seen in this study.	Smoking impacts carcinomatous progression. The most common lesion location was the medial maxillary sinus, maxillary sinus and ethmoid sinus. The interval between initial resection and diagnosis of malignancy was 73 months.
Mazlina et al. [15]	2006	Case report	D	1	N/A	N/A	A case with a multicentric IP in the sinonasal region and middle ear of a 54 year old man.
Bernat et al. [16]	1998	Case report	D	1	N/A	N/A	A case where an epidermoid carcinoma developed from the inverted papilloma.
Dingle et al. [17]	2012	Case report	D	1	N/A	N/A	The first case of bilateral IP of the middle ear with intracranial involvement and malignant transformation.
Mathew et al. [18]	2012	Case report	D	1	N/A	N/A	A case of SIP (malignant) with neck metastasis.
Islam et al. [19]	2014	Case report	D	1	N/A	N/A	A case with IP transformation to SCC of the lacrimal sac, bilateral, and development of distant metastasis.
Sharma et al. [20]	2015	Case study	D	1	N/A	N/A	Follow up should include complete head and neck examination for patients with a typical SIP, as SIP can be re-occur in many locations.
Balasubramani et al. [21]	2009	Case study	D	1	N/A	N/A	IP-SCC can invade into the pituitary fossa mimicking a pituitary macroadenoma.
Garcia et al. [22]	2014	Case study	D	1	N/A	N/A	A case of IP-SCC arise from maxillary sinus extending to the mouth