Angiomatous Nasal Polyp: The Great Emulator—A Case Report

Abstract

Angiomatous nasal polyps are rare, benign and non-neoplastic lesions rarely reported in literature. Clinically and radiologically it mimics sinonasal neoplasm. In 5% of inflammatory or allergic sinonasal polyps, extensive vascularisation and ectasia with pseudoamyloid deposition is noted. Pathognomic features of ANP are angiogenesis, accumulation of amorphous eosinophilic substance and atypical stromal cells. In this case report we elaborate probable etiology, clinical features, histopathology (HPE) and radiological findings in a unique case of ANP which mimicked sinonasal mass. Patient presented with U/L nasal obstruction and recurrent episodes of epistaxis. He was operated for similar complaints 8 years ago, details of which were not available with the patient. Patient was recently diagnosed with Hypertension (HTN) and Diabetes Mellitus (DM). On Diagnostic Nasal endoscopy and Radiological imaging, the nasal mass appeared to be a sinonasal vascular lesion. Revision Functional endoscopic sinus surgery was done and on HPE, ANP was reported. Thus, we conclude that ANPs are rare pathological entity and can cause a significant diagnostic dilemma. Thorough knowledge about the clinical presentation and histopathological features is important in establishing an early definitive diagnosis. Also we have made an attempt to establish the possible role of DM and HTN in pathophysiology of ANP.

Introduction

ANP account for 5% of all inflammatory polyps. Most common clinical presentation includes U/L nasal obstruction, recurrent episodes of epistaxis, rhinnorhea, headache, hyposmia, visual disturbances [1, 2]. ANP clinically and radiologically simulates other pathology like inverted papilloma, Juvenile nasopharyngeal angiofibroma, Hemangioma and Malignant tumours [3–5]. DM and HTN have a role in pathophysiology of ANP [6]. HPE have a vital role in diagnosis and differentiating ANP from other vascular lesions. [1]

Case Report

A 48 year old male, presented to Emergency Department with a 5 month history of recurrent epistaxis, right sided progressive nasal obstruction and rhinorrhea. ENT referral was done for anterior nasal packing as bleeding could not be controlled with conservative measures. The patient’s co-morbidities included recently diagnosed HTN and DM which was well controlled with medications. The patient had history of transient ischemic attacks for which he was on Aspirin.

In the past, 8 years ago, the patient underwent nasal surgery for similar complaints, details of which were not available with the patient. On removal of the packs 48 h later there was no bleeding. DNE was done which revealed postoperative changes along right medial maxillary wall. A reddish lobulated mass noted protruding in right nasal cavity extending from right maxillary sinus covered with blood tinged mucus and secretions. Biopsy was not attempted on suspicion of vascular pathology. Patient was discharged and a computed tomography (CT) scan with contrast of the paranasal sinuses was done on an outpatient basis to assess the extent of the pathology.

The CT scan revealed complete opacification of right maxillary sinus with sclerosis and bony erosions of the right maxillary wall (Fig. 1).

Fig. 1.

CT imaging of PNS Coronal view

Postoperative changes seen in the medial wall of right maxillary sinus. A completely opacified right maxillary sinus, with few areas of sclerosis and erosions in anterior and posterolateral walls. Bone remodelling and demineralisation of medial maxillary wall.

The radiological features were pathognomic of sinonasal inverted papilloma. Blood investigations were within normal limits. A Revision Functional endoscopic sinus surgery was planned where a polypoidal hemorrhagic mass was seen originating within the maxillary antrum with postoperative changes noted along the medial wall. Entire mass was removed and sent for HPE. The intra-operative findings were consistent with a sinonasal inverted papilloma. The patient’s recovery was uneventful. On histopathology, ANP was reported (Fig. 2).

Fig. 2.

Lightmicroscopy. a Variable size small ectatic blood vessels with foci of vascular congestion b A polypoidal mass lined by flattened surface respiratory epithelium, stromal hemorrhage and telangiectasia

Discussion

ANP is classified into five types oedematous, glandular, fibrous, cystic and angiectatic. ANP account for only 4–5% of all nasal polyps. Synonyms used for this pathological entity within the literature are nasal polyp with haemorrhage and necrosis, sinonasal organized haematoma, inflammatory granuloma telangiectaticum, vascular granuloma, pseudo-angioma, and angiomatous polyp [1]. The most common presentation is recurrent episodes of epistaxis. They simulate malignancy by displaying aggressive clinical behaviour, rapid growth and widespread bone destruction with deformity [2].

ANPs are one of the variants of antrochoanal polyp [1, 2]. Batsakis mentioned in their study that at the sinus ostium, vascular compression of the polyp leads to infarction followed by reparative changes and neovascularisation. They also elaborated vascular compromise at four vulnerable sites that is the ostial exit site, the posterior end of the inferior turbinate, the posterior choanae and the most dependent part within the nasopharynx. The Extravascular oedema occurs as a result of compression, followed by infarction and stasis [2]. ANP have a prominent component of capillary-type blood vessels and intraluminal thrombosis, which is usually not seen in non angiomatous polyps. They are difficult to remove en bloc since they are often infarcted and very fragile. Through the thin walled blood vessel extravasation of blood component occurs which leads to large perivascular pools of eosinophilic material, which gives characteristic histological appearance [1–5].

Postulated role of DM and HTN in pathophysiology of ANP is that the elevated blood sugar level and elevated blood pressure makes the blood vessels more susceptible to damage and thus formation of thrombosis and atherosclerosis. Anticoagulant medications like aspirin causes blockage of prostaglandin production, dilatation of blood vessels and prevent clot formation, thus this leads to hemorrhage [6].

Radiologically the differential diagnosis of ANP is juvenile angiofibroma, hemangioma and inverted papilloma. The incidence of angiofibromas occurs almost exclusively in young adolescent males, thus ANP should always be considered in elderly female patients presenting with similar features. However in contrast, nasopharyngeal mass of any size growing sufficiently to involve and expand the posterior nasal vault and not extending into the pterygopalatine fossa or sphenoid sinus is not a feature of an angiofibroma, thus diagnosis points towards ANP [1–4]. In adolescent and young patients, hypovascular or avascular lesions on angiography can help differentiate them from angiofibroma [1].

Hemangioma classically arises from the nasal septum or vestibule, and on CT scan they show greater contrast enhancement then ANPs. Based on clinical and radiological features Inverted papilloma is difficult to distinguish from ANP. However more prominent vascular changes are noted in ANPs [2–6].

In general, ANPs on CT scan show features of opacified minimally enhancing lesion involving the sinus wall and the nasal cavity with demineralization of adjacent bony wall [3, 4]. Functional endoscopic sinus surgery is the treatment of choice [3–6].

Conclusion

• ANPs are rare and distinct type of inflammatory sinonasal polyp which can clinically and radiologically mimic a sinonasal benign or malignant lesion.

• ANP can create a diagnostic dilemma so better understanding of differential diagnosis is a must for differentiating ANP with other conditions like inverted papilloma, haemangioma, nasopharyngeal angiofibroma and malignancy.

• A proper understanding of clinical presentation and histopathological features is important in establishing an early definitive diagnosis and thereby guiding management.

• The most common clinical presentation of ANP is U/L nasal obstruction, recurrent episodes of epistaxis and rhinorrhea.

• Possible role of DM and HTN in pathophysiology of ANP is that it leads to damage of blood vessels and formation of atherosclerosis. Role of aspirin in formation of ANP is that it causes vessel dilatation and inhibition of clot formation, thus leads to hemorrhage.

• Most common radiological finding is expansile heterogeneous mass in maxillary sinus with bone remodelling and demineralisation of the bony walls of the sinus.

• The Histopathological finding is well defined polyp covered with respiratory-type epithelium. The stroma shows marked hemorrhage and extravasation of eosinophilic fibrinoid material with neovascularization and infiltration of chronic inflammatory cells. Blood vessels are irregularly shaped ectatic thin-walled with hemorrhage and stromal fibrinoid material deposition.

Authors' Contribution

This manuscript has been read and approved by all the authors and the requirements for authorship have been met. Each author approves that the manuscript represents original work.

Funding

No funding was received to assist with the preparation of this manuscript. The authors have no financial or proprietary interests in any material discussed in this article.

Declarations

Conflict of interest

The authors declare that they have no known competing financial or non financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Ethical Approval

Ethical Committee Approval was done.

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