The cytomorphologic spectrum of salivary gland type tumors in the lung and mediastinum: a report of 16 patients.

In the lung and mediastinum, salivary gland type tumors (SGTTs) can occur as either primary tumors or metastases from tumors arising in the major or minor salivary glands. This study reviewed the cytology cases of SGTTs in the lung and mediastinum diagnosed over a six-year period at our institution. The specimens included a total of 22 exfoliative or aspiration cytology specimens identified in 16 patients. Two of the cases were primary tumors: adenoid cystic carcinoma (ACC) of the trachea and mucoepidermoid carcinoma (MEC) of the thymus. The remaining 20 tumors were metastases from the parotid, submandibular gland, tongue, nasal cavity, or soft palate. Eight of the 16 patients (50%) had a diagnosis of ACC, four (25%) had salivary duct carcinomas, two (12.5%) had MECs, one (6.25%) was a basaloid tumor, and one (6.25%) was polymorphous low grade adenocarcinoma. In our series, these SGTTs were more commonly metastatic in the lung or mediastinum (87.5% of the patients), and the most common histological subtype was ACC, followed by SDC. This study also illustrates the cytomorphologic features and diagnostic pitfalls of these unusual SGTTs.