Salivary duct carcinoma of the sublingual gland--a case report

RATIONALE: Pleomorphic adenoma is the most common neoplasm of major and minor salivary gland origin, followed by infectious reasons and sialolithiasis. Less common are adenocarcinomas presented. The salivary duct carcinoma represents a rare variant of the group of adenocarcinomas originated from the salivary glands, especially extremely rare from minor salivary gland origin. CASE REPORT: We report about a 52 year old male patient presenting with painless, non-ulcerating tumor at the floor of the mouth. Since 2 weeks ingestion was painful. Further ENT-investigations including endoscopy and scans (MRT, ultrasound) showed no pathology. In particular, growth of cervical lymph nodes and distant metastases were not revealed. A biopsy showed a rare salivary duct carcinoma of comedo-type originated from the left sublingual salivary gland. The patient underwent an operation: the tumor was extirpated in toto, and, as the pathohistological investigation confirmed, in sano. Additionally a neck dissection at the left side was performed, followed by the radiation of the tumor region and the lymphatic neck regions, after sufficient reconvalescence. The tumor-classification was pT3, pN0. Since 3 years no recurrence of the tumor was confirmed. DISCUSSION: Salivary duct carcinoma is a rare, high-grade malignant epithelial neoplasm, which occurs almost exclusively in the parotid. As presented, it can also occur in minor salivary glands. Histologically it is composed of structures that resemble expanded salivary glands. Comedonecrosis of these structures is a frequent feature. There is some histologic similarity to intraductal carcinoma of the breast. Differential diagnosis comprises adenoid cystic carcinoma, metastases of other adenocarcinomas, such as the carcinoma of the thyroid gland and the comedocarcinoma of the breast. Because of its poor prognosis a rapid and radical therapy is recommended. CONCLUSION: A rare case of a salivary duct carcinoma of sublingual salivary gland origin is presented. Usually the prognosis is poor. The adequate therapy is the complete surgical extirpation including the surgery of the regional lymphatic nodes and the additional radiotherapy.