Adult parotitis exhibits various appearances on images. The purpose of this study was to investigate the imaging features of adult parotitis, focusing on the inflammatory spread in and around the parotid gland on CT images. We investigated 21 patients who were clinically and radiologically diagnosed with parotitis, including patients with concomitant occurrences of sialolith or Sjören's syndrome. Intra-glandular spread was divided into 13 diffuse types and 8 focal types. There was a significant difference in duration from the first onset of symptoms between the diffuse and focal types. Six of 8 patients showing focal type spread were associated with the concomitant occurrence of sialolith or Sjören's syndrome. Extra-glandular spread was observed in 13 (62%) patients. Of them, 12 (92%) showed subcutaneous fat tissue and/or masticator space involvement. Involvement of the parapharyngeal space and the superficial area just below the gland was observed in 4 and 7 patients, respectively. The appearance of extra-glandular spread was influenced by intra-glandular appearance and concomitant disease. The spread of adult parotitis possessed characteristic features in relation to clinical findings and concomitant disease. CT examination appeared to be effective for these diagnoses.

Ultrasonography may provide some information as to the tissue characteristics of tumorous lesions in the floor of the mouth, which have not been sufficiently clarified. Ultrasonographic imaging characteristics of these lesions are presented and the differential diagnoses are discussed. Ultrasonographic images of 5 patients with metastatic lingual lymph nodes (squamous cell carcinoma), lymphangioma, Schwannoma, ranula and dermoid cyst are presented. The literature on the imaging features of tumorous lesions in the floor of the mouth was searched using Medline. Five cases of tumorous lesions in the floor of the mouth are presented. The differential diagnosis through a review of the references was discussed. Ultrasonographic images clearly showed the internal structures of the mass. The homogeneity varied according to the degree of closeness of the cells and tissues, or the presence of fluid, hemorrhage, cystic degeneration and calculus. The echogenicity was due to the high acoustic impedance of calculus, cholesterol, and so on. The imaging features varied according to the ratio of the tissues, such as fat and fibrous tissue (in lipoma), or cholesterol and keratin (in dermoid cyst). A high vascular mass indicated malignant salivary gland tumors and hemangioma. In conclusion, ultrasonographic images revealed the distinctive features of the lesions and were useful for the differential diagnosis. Therefore, ultrasonography could be used to conjecture the content of the lesions and is considered to be useful for easy and accurate diagnosis prior to treatment.