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Pancoast syndrome (Pancoast’s syndrome) typically results when a malignant neoplasm of the superior sulcus of the lung (lung cancer) leads to destructive lesions of the thoracic inlet and involvement of the brachial plexus and cervical sympathetic nerves (stellate ganglion). [1, 2, 3] This is accompanied by the following:

Severe pain in the shoulder region radiating toward the axilla and scapula, with later extension along the ulnar aspect of the arm to the hand Atrophy of hand and arm muscles Horner syndrome ( ptosis, miosis, hemianhidrosis, enophthalmos) Compression of the blood vessels with edema Most Pancoast tumors are squamous cell carcinomas (SCCs) or adenocarcinomas; only 3-5% are small cell carcinomas. Squamous cell carcinoma occurs more frequently, although large cell and undifferentiated types are also common. Adenocarcinoma is sometimes found in this location and can even be metastatic. Involvement of the phrenic or recurrent laryngeal nerve or superior vena cava obstruction is not representative of the classic Pancoast tumor.

Once universally fatal, Pancoast tumors are currently treatable with outcomes similar to those of other stage-matched non–small cell lung cancers. [4] Careful assessment and appropriate staging are performed before surgery, and selected patients are administered preoperative irradiation of 30 Gy over 2 weeks. After an interval of 2-4 weeks, surgical resection of the chest wall and lower brachial plexus and en bloc lung resection produces a 5-year survival rate of 30%. Contraindications to surgical management include the following:

Extension of the tumor into the neck or vertebrae Presence of substantial mediastinal lymph nodes Peripheral tumor dissemination Protocols that use combinations of radiation therapy, chemotherapy, and surgery are currently being studied to determine the best therapy. Pathophysiology Pancoast tumors are a subset of lung cancers that invade the apical chest wall. Because of their location in the pleural apex, they invade adjoining tissue. Although other tumors may have a similar clinical presentation because of their location at the thoracic inlet, the most common cause is believed to be a bronchogenic carcinoma arising in or near the superior sulcus and invading adjacent extrathoracic structures by direct extension. Location, rather than pathology or histology of origin, is significant in producing the tumor’s characteristic clinical pattern. [5]

The bulk of a true Pancoast tumor is extrathoracic, originating in an extreme peripheral location with a plaquelike extension over the lung apex and principally involving the chest wall structures rather than the underlying lung parenchyma. Bronchogenic carcinomas occurring in the narrow confines of the thoracic inlet invade the lymphatic vessels in the endothoracic fascia and include, by direct extension, the following structures:

Intercostal nerves Lower roots of the brachial plexus Stellate ganglion Sympathetic chain Adjacent ribs and vertebrae. Carcinomas in the superior pulmonary sulcus produce Pancoast syndrome, thus causing pain in the shoulder and along the ulnar nerve distribution of the arm and hand. [6] (These carcinomas also cause Horner syndrome.) These apical lung tumors tend to be locally invasive early. In the absence of metastases and regional nodal involvement, these apical cancers can be successfully treated.

The tumor may invade the bony structures of the chest, including the first or second thoracic vertebra or the first, second, or third rib. In a review of 60 patients with Pancoast tumors, Maggi et al found radiographic evidence of rib erosion in 50%; an almost equal percentage demonstrated involvement of the first or second rib, and 20% had involvement of the third rib. One patient had involvement of all 3 ribs. [7]

The tumor can also invade the first or second thoracic vertebral bodies or intervertebral foramina. From this point, it can extend to the spinal cord and result in cord compression. The subclavian vein or artery may also be invaded.