We report a case of sialolithiasis in the parotid glands that passed spontaneously during follow-up with some discussion based on the literature. The patient was a 62-year-old male who visited our hospital with the chief complaints of spontaneous pain and swelling around the left auricular area. Swelling and tenderness in the outer part of the left parotid gland area as well as redness and swelling with pus discharge with compression in the left parotid orifice were found during examination. Panoramic radiography showed relatively well-circumscribed shapeless opacities in the distal left second molar of the upper jaw. MR imaging revealed significant swelling in the left parotid gland area with low signal intensity on the T1-weighted image, low to moderate signal intensity on the T2-weighted image, moderate to high signal intensity on the fat-suppressed T2-weighted image, approximately 1-cm oval area with no signal within the buccal gingival soft tissue of the left molar of the upper jaw, and behind there, significant expansion of the parotid duct. A hard material, probably sialolithiasis, passed spontaneously during brushing in the morning of the next day of the initial examination, and the patient visited the hospital with the excretion. The sialolithiasis was almost round, yellowish-white, somewhat rough, and 11×7mm in size. For this case of sialolithiasis in the parotid glands, a CT examination was not performed and images could not be accurately obtained at the initial examination. It is therefore important to perform a comprehensive diagnosis, from clinical diagnosis to imaging diagnosis including panoramic radiography, CT examination, MR imaging, or ultrasonography.
