Following breast and lung cancers, renal cell carcinoma (RCC) is the third most frequent cancer to metastasize to the head and neck region, though such cases are rarely reported. Distinguishing between malignant tumors of salivary gland origin and metastatic RCC is very important. The case of a 75-year-old man with an oral cavity lesion in the left buccal submucosa measuring 40×30 mm that had grown substantially over several weeks is presented. His medical history included left kidney cancer 26 years earlier and a malignant myoepithelioma of the left buccal region 7 years earlier. It was suspected that this lesion was a recurrent malignant myoepithelioma as it appeared at the same site as the previous operation. Surgery was performed, and metastatic RCC was confirmed upon pathological examination. The diagnosis of metastatic RCC was made by immunohistochemical examination, which also excluded malignant myoepithelioma and other clear cell carcinomas of salivary gland origin. Metastatic RCC must be considered in the differential diagnosis of a new oral cavity lesion presenting in a patient with a past history of kidney cancer. Thus, immunohistochemical staining is required to distinguish malignancies of salivary gland origin, including malignant myoepithelioma, from metastatic RCC.

Acute osteomyelitis exists as a refractory disease even now, which usually exhibits systemic symptoms such as fever or malaise and local redness or swelling. The present paper describes a case of acute osteomyelitis of the mandible that was rapidly progressing without typical symptoms. The patient had liver cirrhosis, which should be one of the systemic factors that affect immune surveillance and metabolism. Actinomycotic druses and filaments were detected from the sequestrum. These were considered to play a role in the rapid progression of osteomyelitis without typical symptoms. There has been no evidence of local recurrence 24 months after surgery.

Dermoid cysts are benign lesions of congenital origin, and those in the head and neck region are usually present as a midline neck mass. They rarely appear in the lateral neck. This article describes the clinical presentation and histopathologic features of an extremely rare case of lateral dermoid cyst included within the submandibular gland in a 58-year-old man. The etiology of the cyst is also discussed.

Nasolabial cysts are uncommonly diagnosed non-odontogenic soft tissue lesions occurring close to the nasal alar region of the face. Patients usually present with a slowly enlarging asymptomatic swelling. Diagnosis is usually made in the early stages because of the esthetic effects. Histologically, the lesion is lined with non-keratinized squamous epithelium or, more frequently, pseudostratified columnar epithelium with goblet cells. These cysts are most often diagnosed in the fourth decade of life. However, we report a case of nasolabial cyst in an 80-year-old woman, and discuss the diagnosis, differential diagnosis, and treatment with reference to the literature.