Imaging features of rhinosporidiosis on contrast CT

Context: Rhinosporidiosis is a chronic granulomatous disease endemic in certain regions of India. Computed tomography (CT) imaging appearances of rhinosporidiosis have not been previously described in the literature. Aims: To study imaging features in rhinosporidiosis with contrast-enhanced CT and elucidate its role in the evaluation of this disease. Materials and Methods: Sixteen patients with pathologically proven rhinosporidiosis were included in the study. Contrast-enhanced CT images were analyzed retrospectively and imaging findings were correlated with surgical and histopathologic findings. Results: A total of 29 lesions were found and evaluated. On contrast-enhanced CT, rhinosporidiosis was seen as moderately enhancing lobulated or irregular soft tissue mass lesions in the nasal cavity ( n = 13), lesions arising in nasal cavity and extending through choana into nasopharynx ( n = 5), pedunculated polypoidal lesions arising from the nasopharyngeal wall ( n = 5), oropharyngeal wall ( n = 2), larynx ( n = 1), bronchus ( n = 1), skin and subcutaneous tissue ( n = 2). The inferior nasal cavity comprising nasal floor, inferior turbinate, and inferior meatus was the most common site of involvement ( n = 13). Surrounding bone involvement was seen in the form of rarefaction ( n = 6), partial ( n = 3) or complete erosion ( n = 3) of inferior turbinate, thinning of medial maxillary wall ( n = 2), and septal erosion ( n = 2). Nasolacrimal duct involvement was seen in four cases. Conclusions: Contrast-enhanced CT has an important role in delineating the site and extent of the disease, as well as the involvement of surrounding bone, nasolacrimal duct and tracheobronchial tree. This provides a useful roadmap prior to surgery.