tumors of the diaphragm
Primary tumors of the diaphragm are very rare. Benign tumors are most common, with lipomas and cystic masses such as bronchogenic and mesothelial cyst. Other benign tumors include hemangioma, angiofibroma, neurofibroma, schwanoma, leiomyoma, teratoma, endometrioma, and desmoid tumor. Most malignant tumors are sarcomas of fibrous or muscular origine. They include fibrosarcoma, malignant fibrous histiocytoma, hemangiopericytoma, germ cell tumors, pheochromocytoma, and leiomyosarcoma. Radiologically, most diaphragmatic tumors present as smooth or lobulated soft-tissue masses protruding into the inferior portion of the lung or can resemble a diaphragmatic hernia, eventration or plural lesion. CT or MR imaging can easily confirm the presence of a mass in the diaphragm. When the tumor is large, it may not be possible to determine whether it arise from diaphragm, pleura, or lungs, or abdominal viscera, even on CT, MR imaging, or ultrasound. Thoracic or abdominal tumors may secondarily involve the diaphragm by direct extension. Such tumors include bronchogenic carcinoma, mesothelioma, and other primary or secondary pleural or chest wall malignancies, hepatic neoplasms, and peritoneal carcinomatosis. Diaphragmatic metastases, derived from either lymphatic or hematogenous spread, are rare. Clinical symptoms or radiographic features are usually related to the presence of neoplasm in contiguous structures or elsewhere, rather than in the diaphragm itself.