Epithelial-myoepithelial carcinoma (EMC) is a rare tumor constituting less than 1 % of all salivary gland tumors. This neoplasm most often involves the parotid glands, with less frequent involvement of the submandibular or minor salivary glands. This case report describes EMC arising from a minor salivary gland in the buccal mucosa. A 71-year-old Japanese man with a painless submucosal mass in the left buccal region was referred to our hospital. The patient stated that the tumor had been present for more than 4 years and was painless but increasing in size. Oral examination showed a mobile, well-defined mass of approximately 19 9 15 mm; its surface was covered mostly by normal mucosa. Magnetic resonance imaging showed a mass with well-defined borders and relative homogeneity internally. Incisional biopsy led to a histological diagnosis of a suspected pleomorphic adenoma or low-grade malignant tumor originating from the salivary gland. The patient underwent surgical excision under general anesthesia to obtain a definitive diagnosis, and EMC was diagnosed based on histopathological and immunohistochemical examination of the whole specimen. Because the surgical margins were positive in some areas, the patient underwent external postoperative radiotherapy (total of 60 Gy at 2 Gy/day). Recovery was uneventful, and good function returned after postoperative treatment. Four years after tumor resection and radiotherapy, no recurrence had been detected and no other lesions had developed.
Iron (totalling 7.5 mg per mouse in three doses) was injected into hairless mice to determine the relationship between skin pigmentation and hemosiderin deposition. The skin color reached its maximum 24 to 48 hours after the last injection and then gradually faded over the subsequent 8 months. In the skin, hemosiderin granules were present extracellularly between collagen bundles as well as within dermal macrophages, Langerhans cells and indeterminate dendritic cells of the epidermis. A larger amount of iron was deposited in the facial than in the dorsal skin, resulting in darker pigmentation of the former. This study suggests that brownish discoloration of skin in hemochromatosis might be attributable in some degree to accumulation of hemosiderin and that pronounced hyperpigmentation of the face in hemochromatosis might be due to increased activation of melanocytes by a high content of hemosiderin.
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