Diagnosis: Infarcted angiomatous polyps of the maxillary sinus
Infarcted angiomatous polyp, which is a rarely reported subtype of inflammatory sinonasal polyps, is characterized by dilated, large vascular spaces resulting from extensive vascular proliferation and ectasia. The angiomatous polyps usually correspond to the vascular compromised nasochoanal part of sinochoanal polyps.1- 3The compromise of their vascular supply will lead to infarction, venous stasis, and thrombosis. The clinical, radiologic, and pathologic features of this disease may simulate a neoplastic process and can sometimes be mistaken for vascular neoplasms, eg, angiofibroma.4,5
The usual presenting symptoms of angiomatous polyps are nasal obstruction, epistaxis, and facial swelling.1- 5The striking clinical features in this case were the extension of the mass into the right nasal cavity, through the medial sinus, and orbital symptoms such as exotropia and diplopia resulting from bulging of the mass into the orbit, which raised suspicion of a malignant or local invasive tumor. However, the relatively long history of symptoms was more consistent with a benign lesion. Also, with extremely rare exception, juvenile angiofibromas occur only in young men rather than in elderly persons, as in the present case.4,6
Radiographically, an angiomatous polyp of the maxillary sinus presents as a soft-tissue mass with or without bony expansion, thining, demineralization, and extension into adjacent spaces on computed tomographic scans. These features can easily be confused with those of juvenile angiofibroma, inverted papilloma, and malignant tumors; however, bony destruction has rarely been reported with benign sinonasal polyps.
The unenhanced MRIs showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images, depicting the typical appearance of a sinonasal polyp. Nevertheless, most benign uncomplicated polyps are homogeneous, and the heterogeneity on the postgadolinium T1- and T2-weighted images in this case was an indication that the lesion was vascular, infarcted, or hemorrhagic. Also, a low signal in the posterior medial aspect of the right maxillary sinus on T2-weighted images implied old blood product. On gadolinium-enhanced MRIs, the tumor showed strong enhancement, mimicking hypervascular lesions.5Therefore, it is important to distinguish angiomatous polyps from hypervascular lesions such as angiofibromas because of the likelihood of a severe intraoperative hemorrhage. However, the radiologic features that are specific to juvenile angiofibromas, such as nasopharyngeal mass, widening of the pterygopalatine fossa, bowing of posterior wall of the maxillary sinus, and flow void on MRI scans, were absent in this case.4- 6
According to Batsakis and Sneige,3the choanal polyp that originates within a confined space and passes through a constricted ostia is particulary susceptible to vascular compromise and formation of an agiomatous polyp. Occlusion of feeder vessels in the polyp sets up the following sequence: (1) dilation and stasis of feeder vessels, (2) edema, (3) infarct, (4) neovascularization, (5) subsequent occlusion, and (6) another infarct.
The treatment of choice is surgical resection, followed by observation. The approach should be adjusted according to the location of the lesion. In the present case, the mass was successfully removed via a transnasal endoscopic approach, and there was no recurrence 6 months after the operation.
Return to Quiz Case 1.
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2010;136(7):742. doi:10.1001/archoto.2010.96-b