Malignant pleural mesothelioma metastatic to the submandibular salivary gland, simulating glandular hypertrophy, diagnosed by fine-needle aspiration biopsy: a case report and literature review

BACKGROUND Malignant mesothelioma is a rare neoplasm that generally develops in the pleural or peritoneal cavity. Distant metastases are common; it rarely metastatizes to the head and neck region. CASE PRESENTATION A 54-year-old white man, a non-smoker, was treated with chemotherapy, surgery and radiation for a malignant pleural mesothelioma. Seven months after the last treatment, he developed a right submandibular enlargement: clinical examination, ultrasound and computerized tomography scans revealed a salivary gland hypertrophy. Anti-inflammatory and antibiotic treatment was then started, without improvement. An ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) showed atypical mesothelial cells with nuclear enlargement and increased chromatin representation. Immunocytochemistry showed positivity for calretinin and WT-1.A diagnosis of right submandibular salivary gland involvement from mesothelioma was established, allowing an adequate treatment. CONCLUSION We report a very rare site of metastasis from malignant pleural mesothelioma. We suggest that US-guided FNAB is a useful, quick, and cheap procedure for a definite diagnosis.