Inverted papilloma: evaluation with MR imaging.

Abstract

The authors examined the magnetic resonance (MR) appearance of inverted papillomas to determine if this histologically benign lesion could be distinguished from malignancies of the sinonasal cavity. MR images in 10 patients with histologically proved inverted papilloma were retrospectively reviewed. The signal intensity of inverted papillomas on short repetition time (TR) images was iso- to slightly hypertintense to muscle in all 10 patients. Inverted papillomas had intermediate signal intensity on the long TR/echo time (TE) images. The tumors were iso- or slightly hypointense to fat on long TR/short TE images. In the seven patients who received gadopentetate dimeglumine, all inverted papillomas showed solid inhomogeneous enhancement. A review of eight sinonasal malignancies showed no distinctive signal intensity or enhancement characteristics to help differentiate inverted papillomas from various malignant tumors. The authors conclude that there is no signature MR appearance for the benign inverted papilloma. The main utility of MR imaging is in defining the extent of the lesion.

Sinonasal Inverted Papilloma: Value of Convoluted Cerebriform Pattern on MR Imaging

“…It would be useful for planning therapeutic strategies if the CCP on MR imaging can suggest the preoperative diagnosis of IP, because more aggressive surgical approaches would be needed for IPs concomitant with SCC and other malignant sinonasal tumors. However, one previous study reported by Yousem et al 13 failed to find this sign as a specific MR imaging finding to diagnose IP. The purpose of this study was to evaluate the diagnostic accuracy of a CCP depicted on MR imaging for distinguishing IP from other malignant sinonasal tumors in a relatively large number of patients.…”

“…[3][4][5][6][7][8][9][10][11][12] Although CT and MR imaging are useful for preoperative assessment of sinonasal IP, differentiation of IP from other malignant sinonasal tumors is often difficult because of a significant overlap of the imaging features. [13][14][15][16][17][18][19] Barnes et al 20 described a distinctive gross mucosal morphology of IP, a so-called convoluted cerebriform pattern (CCP), which can be reflected on MR imaging by the characteristic alternating hypointense and hyperintense bands on T2-weighted and contrast-enhanced T1-weighted images, as reported by Ojiri et al 17 and supported by Maroldi et al 19 years later. It would be useful for planning therapeutic strategies if the CCP on MR imaging can suggest the preoperative diagnosis of IP, because more aggressive surgical approaches would be needed for IPs concomitant with SCC and other malignant sinonasal tumors.…”

“…[6][7][8] Preoperative evaluation by using cross-sectional imaging, such as CT and MR imaging, is essential for the selection of surgical options by correctly identifying the location and extent of the tumor, and postoperative follow-up examinations at regular intervals are also highly recommended for the early detection of the recurrent disease. [11][12][13][14][15][16][17][18][22][23][24] However, differentiation of IP from other malignant sinonasal tumors by analyzing the internal characteristics on radiologic imaging is often difficult, because there is a significant overlap between those diseases. 15,16,19 IP is seen pathologically as a vascular mass with prominent mucous cyst inclusions interspersed throughout the epithelium and a high intracellular glycogen content.…”

“…5,15 On physical examination, IP presents as a polypoid growth covered by a convoluted cerebriform mucosa, called a CCP, as described by Barnes et al 20 This gross morphology, created by the juxtaposed epithelial and stromal layers, results in a peculiar pattern on MR imaging, manifesting as the alternating hypointense and hyperintense bands, which has been described under the various terms. 13,17,19 Yousem et al 13 used the term "septate striated appearance" and noticed it in 5 (50%) of 10 patients with IP on T2-weighted images. However, the researchers did not impart much importance to it because it was also seen in 2 of 8 other sinonasal malignancies.…”

Sinonasal inverted papilloma: narrative review

“…The main utility of MRI is in defining the extent of the lesion and differentiating inverted papilloma from inspissated mucus. 2,38 Magnetic resonance imaging is ideal for assessment of intra-cranial and intra-orbital tumour extension. 6 Early osteitic changes appear hypointense on T1-weighted images and hyperintense on T2-weighted images.…”