Sinochoanal polyp and its variant, the angiomatous polyp: MRI findings

Abstract

The angiomatous polyp corresponds to the vascular compromised nasochoanal part of a sinochoanal polyp. We describe the MRI characteristics of such lesions in four patients. All patients had an angiomatous polyp, in three cases as part of an antrochoanal polyp, and in one case as part of a sphenochoanal polyp. The unenhanced MR images depicted the typical appearance of a sinochoanal polyp, hypointense on T1-weighted and hyperintense on T2-weighted images. On gadolinium-enhanced MR images, the sinusal part showed little or no peripheral enhancement; however, the nasochoanal part, corresponding to the angiomatous polyp, showed strong enhancement. An angiomatous polyp mimics a hypervascular mass lesion on enhanced MR studies. The anatomic location and association with a sinusal polyp allows the correct diagnosis.

MR Evaluation of Sinonasal Angiomatous Polyp

“…2 This entity has been described in the literature in different terms, including cavernous hemangioma, [3][4][5][6][7] organized or organizing hematoma, [8][9][10][11] hematoma-like mass of the maxillary sinus, 12 and SAP. 1,2,13,14 This lesion is difficult to remove en bloc and is easily broken during excision, so the sampling inconsistencies related to lesional fragility are likely responsible for the wide variation in pathologic description and terminology. 12 In addition, in China this entity is more often called "nasal polyp with hemorrhage and necrosis," but it shares all the same clinicopathologic and imaging features of the abovementioned 4 lesions.…”

“…3,[8][9][10][11] The conventional MR imaging findings of SAP, however, have been described in only a few articles. 2,4,8,13 In addition, its features on DCE MR imaging and DWI have not been systematically reviewed, to our knowledge. The purpose of this study was to describe not only the characteristics of conventional MR imaging but also those of DCE MR imaging and DWI in SAP.…”

Nasal chondromesenchymal hamartoma: a rare nasal benign tumor

“…Hemangioma, angiofibroma, antrochoanal polyp, nasoethmoidal encephalocele, nasal glioma, inverted papilloma, giant cell reparative granuloma, ossifying fibroma, chondro-osseous respiratory adenomatoid hamartoma, and aneurismal bone cysts along with other rare benign pediatric tumors constitute the broad list of differential diagnose. [8,[20][21][22] Exclusion of nasoethmoidal encephalocele and nasal glioma in differential diagnosis is considerably important so as to avoid neurologic complications of surgical therapy. On imaging sections of nasoethmoidal encephalocele, a bone defect is almost always seen with no destruction of the anterior cranial fossa, cystic lesions show a thin peripheral halo with soft central tissue.…”

Angiomatous nasal polyp: Clinical diagnostic dilemma

“…Polyp and usually extend the through the roof of nasopharynx into the sphenoidal sinus and pterygopalatine fossa. Rarely ANPS can also invade into sphenoidal sinus 11 and ethmoidal sinus. 6 Conventional magnetic resonance imaging (MRI) is a better modality for preoperative diagnosis of the angiomatous nasal polyp, and show characteristic hypointensity on T1 weighted images and internal heterogeneous hyperintensity with a peripheral hypointense rim on T2 weighted images, as well as and strong nodular and patchy enhancement on postcontrast MRIs.…”

“…6 Conventional magnetic resonance imaging (MRI) is a better modality for preoperative diagnosis of the angiomatous nasal polyp, and show characteristic hypointensity on T1 weighted images and internal heterogeneous hyperintensity with a peripheral hypointense rim on T2 weighted images, as well as and strong nodular and patchy enhancement on postcontrast MRIs. 2,9,11 Moreover, progressive enhancement on DCE MRI is very important diagnostic clue. 9 Areas of mixed signal intensity on T2 weighted images are supposed to be caused by the extensive areas of organized thrombus and necrosis in that part of polyp and the peripheral hypointense rim on T2 weighted images due to old microhemorrhage with hemosiderin deposition on the surface of the polyp.…”