Fig. 4

Coronal bone window CT images of three different patients with sinonasal disease: 51-year-old female with 4-year history of nasal congestive symptoms and anosmia diagnosed with sinusitis (a); 70-year-old female patient presenting with bloody nasal discharge and right nasal blockage diagnosed with sinonasal carcinoma (b); and 70-year-old female presenting with nasal congestion diagnosed with malignant melanoma (c). Pansinusitis with complete opacification of the paranasal sinuses (a). The bilateral nature of the disease is a sign of benignity whilst the rarefaction and thinning of the bony architecture (arrowed) suggests a more chronic process. Conversely unilateral opacification as demonstrated in (b) and (c) is suspicious for a malignant process. Notice the bony destruction of the inferior turbinate in both cases (arrowed in b and c), which can be difficult to discern from rarefaction (arrowed, a); however, this must be assessed in the context of unilateral disease. The imaging appearances in (b) and (c) are strikingly similar on both CT and MRI (not shown) and were only distinguishable on histology, which confirmed sinonasal squamous cell carcinoma (b) and malignant melanoma (c). Incidental note is made of bilateral maxillary sinus mucus retention cysts (b), identifiable by their rounded, convex contour, and fluid density (arrowhead, b), in contrast to the concave maxillary mucosal thickening (arrowhead, c)