FLEX February 2024

Imaging of Pediatric Head and Neck Masses

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Sinonasal lesions Sinonasal lesions are well delineated on CT. One example is an antrochoanal polyp, which appears as a lobulated hypodense lesion involving the maxillary antrum and nasal cavity, with extension through the choana ( Fig. 21 ). Langerhans cell histiocystosis Involvement of the skull, maxillofacial bones, and hypothalamic–pituitary axis is fairly common in Langerhans cell histiocytosis. 29 CT typically demonstrates circumscribed rounded or oval lytic lesions involving the inner and outer tables of the calvarium, with a characteristic beveled edge configuration, and often a bony sequestrum. An asso ciated enhancing soft tissue mass is present in some cases ( Fig. 22 ). Fig. 21. Antrochoanal polyp. Contrast-enhanced CT with coronal bone windows ( A ) and re constructed axial soft tissue images ( B ) shows a low density lesion partly filling the left maxil lary sinus and posterior nasal cavity. There is extension through the choana into the nasopharynx ( white arrow ).

Fig. 22. Langerhans cell histiocytosis. Axial CT in bone algorithm ( left ) demonstrates a lytic lesion in the left temporal bone with a beveled edge configuration. Coronal CT in soft tissue algorithm ( right ) demonstrates an associated soft tissue mass traversing the inner and outer tables, with extracranial extension.

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