Undifferentiated carcinoma of the parotid gland in a 10-month-old child.

Malignant salivary gland tumors in children are very rare. This report describes the autopsy of a child with parotid gland cancer. The patient, a 10-month-old girl, was admitted to the Nagoya First Red Cross Hospital with facial nerve palsy. Incisional biopsy of a post-auricular tumor was performed, and undifferentiated carcinoma was diagnosed. The patient died 6 months later of respiratory failure due to pulmonary lymphangitis carcinomatosis. Light and electron microscopic and immunohistochemical examinations of the tumor tissue were performed. The tumor cells were arranged in a medullary, sheet-like manner. Keratinization or mucus lakes were not observed. PAS-alcian blue staining demonstrated intracytoplasmic mucus as granules, and also small intercellular droplets of mucus that might otherwise have been unnoticed. Ultrastructurally, some of the tumor cells had tonofilament-like keratin filaments, and also small hollow spaces bounded by microvilli and containing secretory particles. These were stained by antisera against CEA and keratin. These findings are suggestive of differentiation to mucoepidermoid carcinoma. We also review and discuss malignant salivary tumors of epithelial origin in children.