Correlation of computed tomography with pathological features in angiomatous nasal polyps

Abstract

Background: Angiomatous nasal polyps (ANPs), also known as angiectatic polyps, have rarely been reported in the literature. ANPs are characterized by extensive vascular proliferation and ectasia. ANPs can grow rapidly and exhibit aggressive clinical behavior that could simulate malignancy preoperatively, and they are easily confused with other diseases. In the present study, we analyzed the correlation between the computed tomography (CT) findings of nasal angiomatous polyps and their pathological features.

Methods: We evaluated CT findings and pathological features of 31 surgically proven ANPs.

Results: The study population included 16 males and 15 females aged between 27 and 81 years (mean age, 53.5 years). On CT, the masses were heterogeneous; they had a soft tissue density and filled the maxillary and/or nasal cavities. Calcifications were found in 2 of the 31 cases. The lesions showed a clear boundary (15/31). The low-density shading on CT was related to the inflammatory, necrotic, and cystic changes, and the high-density shading on CT was related to hemorrhagic areas of the mass. On contrast-enhanced CT, the center of the lesions was non-enhanced with peripheral intensification due to occlusion or compression of feeder vessels of the polyp center, and the inflammatory cells and neovascularization around the edge of the mass. The most common site of maxillary wall erosion was the medial wall (21/31), followed by the posterior lateral wall (3/31), upper wall (2/31), and septum (3/31). Of these, the nasal cavity and/or maxillary sinus were enlarged in 28 cases. These findings were associated with the chronic progress of nasal angiomatous changes.

Conclusions: CT of ANPs may demonstrate benign bone changes associated with the lesions and may also reflect the fact that ANPs do not invade peripheral soft tissue. CT demonstrated these lesions consistently and provided information useful for surgical planning.

Figure 1. Computed tomography (CT) of a recurrent angiomatous polyp (ANP) in the left maxillary sinus 10 years after ANP removal surgery.

CT showed an irregular, soft-tissue mass in the left maxillary sinus. The density was heterogeneous, and the CT value was approximately 45 HU. The medial maxillary sinus wall was completely destroyed (arrow). The mass involved the left nasal cavity and the left ethmoid sinus. A: noncontrast coronal CT in bone window; B: noncontrast coronal CT in soft-tissue window.

Figure 2. CT of an ANP in the left maxillary sinus involving the ipsilateral ethmoid sinus.

2A: Noncontrast coronal CT in soft-tissue window showed that a high-density mass filled the total left maxillary sinus. The density of the mass was homogeneous. The left maxillary sinus was expansile, and the medial maxillary sinus wall was partially destroyed (arrow). The mass involved the ipsilateral ethmoid sinus. 2B: Contrast-enhanced CT: The mass was non-enhanced.

Figure 3. CT of an ANP in the left maxillary sinus involving the ipsilateral orbit.

A :Noncontrast coronal CT in soft-tissue e window showed that a high-density mass filled the total left maxillary sinus. 3B: Noncontrast coronal CT in soft-tissue e window showed that the lesion was involved in the left orbitand the eyeball shifted laterally (arrow).

Figure 4. CT of an ANP confined within the right nasal cavity.

Noncontrast coronal CT in bone window(A) and in soft-tissue e window(B) showed a soft-tissue mass limited within the right nasal cavity. The edge was irregular, and the nasal septum was compressed and deformed (arrow). The CT value was 26 HU. The walls of the right nasal cavity were intact. The maxillary and ethmoid sinuses were not involved. 4C: Contrast-enhanced CT showed the lesion was non-enhanced.

Figure 5. Grossly, the tumors were purple, necrotic masses.

Figure 6. Pathological findings.

A: Light microscopy showed the tumor covered with pseudostratified, ciliated, columnar epithelium or stratified squamous epithelium with edematous stroma, and many infiltrating inflammatory cells (hematoxylin and eosin staining; original magnification, ×100). B: Proliferation of thin-walled vascular channels. Separated blood vessels exhibited concentric accumulation of amorphous material (hematoxylin and eosin staining; original magnification, ×100).

Figure 7. Pathological finding of edematous stroma and thrombus formation (hematoxylin and eosin staining; original magnification, ×100).

Figure 8. Pathological findings of an earlier organized thrombus (8A: hematoxylin and eosin staining; original magnification, ×400) and organized thrombus (8B: hematoxylin and eosin staining; original magnification, ×200).