Solitary Fibrous Tumor (SFT):
- Distinction: While both lesions can feature a prominent, branching "staghorn" vascular network set within a collagenous stroma, SFT typically displays a characteristic "patternless pattern" of ovoid to spindled cells. Immunohistochemically, SFT is uniquely driven by a NAB2-STAT6 gene fusion and will show strong nuclear positivity for STAT6 and diffuse positivity for CD34, whereas the stromal cells of nasopharyngeal angiofibroma are negative for STAT6 and CD34 but positive for nuclear β-catenin and Androgen Receptor (AR).
Glomangiopericytoma:
- Distinction: Features a diffuse, patternless spindle cell proliferation with a subepithelial clearing (Grenz zone) and perivascular hyalinization. While it also expresses nuclear β-catenin, it is distinguished by positive expression for SMA and nuclear cyclin D1, and it lacks AR expression.
Lobular Capillary Hemangioma (Pyogenic Granuloma):
- Distinction: Characterized by discrete lobules of capillary proliferation separated by fibrous septa, often with surface ulceration and acute inflammation. It lacks the thick fibrocollagenous stroma of an angiofibroma and is negative for nuclear β-catenin and AR.
Biphenotypic Sinonasal Sarcoma:
- Distinction: A cellular, infiltrative spindle cell tumor often featuring trapped respiratory glands. It lacks prominent gaping vascular spaces and will demonstrate positive staining for S100 and SMA.
Sinonasal Inflammatory Polyp:
- Distinction: Displays an edematous stroma with thick basement membranes and a mixed inflammatory infiltrate (eosinophils, lymphocytes, plasma cells). It lacks the specific staghorn vascular pattern and is negative for AR and nuclear β-catenin.

Sinonasal & Nasopharyngeal Lesions

Subcategories

Pathologies