Parotid carcinoma as a second neoplasm following radiotherapy for a nasopharyngeal carcinoma in childhood

• Published in: Stomato-pharyngology Vol. 34; no. 1; pp. 79 - 85
• Main Authors: Shimamura, Akihiro, Sakagami, Tomofumi, Yagi, Masao, Fujisawa, Takuo, Shimizu, Minaki, Suzuki, Kensuke, Iwai, Hiroshi
• Format: Journal Article
• Language: Japanese
• Published: Japan Society of Stomato-pharyngology 2021
• Subjects: nasopharyngeal cancer; parotid cancer; radiation-induced cancer; salivary duct carcinoma
• ISSN: 0917-5105; 1884-4316
• DOI: 10.14821/stomatopharyngology.34.79

We report a 28-year-old male with parotid carcinoma as radiation-induced cancer, who had received irradiation and chemotherapy for nasopharyngeal cancer 15 years prior. Neck dissection was performed for the remaining cervical lymph node metastasis. The following year, metastasis appeared in the thoracic spine. Therefore, radiation chemotherapy was given, and a complete remission was achieved. However, three years after the initial treatment, lung metastasis and hilar lymph node metastasis occurred, thus radiation chemotherapy was performed. Thereafter, chemotherapy was continued because hilar lymphadenopathy remained. The patient was followed up at the age of 25 when the hilar lymph nodes no longer increased. At the age of 28, computed tomography showed a low-density mass occupying the left parotid gland. Fine-needle aspiration cytology revealed malignancy. Extended parotidectomy with neck dissection was performed. The histopathological diagnosis was salivary duct carcinoma. On positron emission tomography 6 months after the surgery, local recurrence and distant metastasis were detected. Patients treated with radiotherapy are at risk of developing a second cancer, especially children and young adults. An additional 18 patients with radiation-induced parotid carcinoma were identified in the literature. To our knowledge, no previous report has compared salivary duct carcinoma in the parotid gland as a second neoplasm following radiotherapy. It is extremely rare for parotid cancers to arise within previously irradiated areas.