Cavitary mucoepidermoid carcinoma of lung with metastases in skeletal muscles as presenting features: a case report and review of the literature.

Mucoepidermoid carcinomas (MECs) of lung are rare neoplasms originating in bronchial submucosal glands and comprising 0.1-0.2% of primary lung cancers. MECs, the most common malignancy in salivary glands, were earlier thought to occur only in salivary glands. Later studies showed that they can arise as a primary in bronchus, esophagus, lacrimal glands, pancreas, thymus and thyroid gland. Initially described as a benign adenoma, it is now considered to be a malignant epithelial tumor. There have been reports of metastases to regional lymph nodes, other parts of the lung and distant organs. Cavitary lesion in MEC of lung is rare. Here, we report a case of MEC of lung with metastases to skeletal muscles of thigh and arm. To the best of our knowledge, this is the only case of MEC of lung presenting with such unusual pattern of metastasis as presenting feature with almost no symptoms of primary lesion.