PANCOAST TUMOR AND SYNDROME
Superior sulcus tumors are located at the apical pleuropulmonary groove adjacent to the subclavian vessels. Superior sulcus tumors received notoriety in reports by Henry Pancoast and are commonly referred to as Pan-coast tumors. Lung cancer is by far the most common cause of Pancoast and superior sulcus tumors. It is more commonly associated with adenocarcinoma but may be caused by any histologic type. A variety of other rare tumors or infectious diseases have occasionally been reported to cause a Pancoast tumor.
Tumors of the superior sulcus may cause shoulder and arm pain (in the distribution of the C8, T1, and T2 dermatomes), Horner syndrome, and weakness of the muscles of the hand. This complex is referred to as Pancoast syndrome. Shoulder pain is the usual presenting symptom and is caused by tumor invasion of the tumor into the chest wall, ﬁrst and second ribs, vertebral body, and possibly the brachial plexus. Pain may radiate up to the head and neck or to the axilla and arm in the distribution of the ulnar nerve. The cause of the pain is frequently misdiagnosed for months as osteoarthritis or bursitis of the shoulder. Horner syndrome consists of ipsilateral ptosis, miosis, enophthalmos, and anhidrosis of half of the face and head and is caused by involvement of the paravertebral sympathetic chain and the inferior cervical (stellate) ganglion. Contralateral facial sweating and ﬂushing have been reported.
Tumor involvement of the C8 and T1 nerve roots may result in weakness and atrophy of the intrinsic muscles of the hand or pain or paresthesias of the fourth and ﬁfth digits and medial aspect of the arm and forearm. Abnormal sensation or pain in the axilla and medial aspect of the upper arm caused by T2 nerve root involvement may be an early symptom. As these tumors progress, they may invade the intervertebral foramina and cause spinal cord compression and paraplegia. This may especially be a problem for patients with progressive disease who have failed local treatment. Tumors with progressive mediastinal involvement may result in phrenic nerve or laryngeal nerve paralysis.
The classic radiographic ﬁnding is that of an apical mass or unilateral apical cap. Occasionally, the abnormality will not be obvious on a chest radiograph; therefore if the diagnosis is suspected, a computed tomography (CT) scan of the chest is required. The CT will demonstrate greater detail and is more likely to elucidate the extent of the tumor locally. Magnetic resonance imaging (MRI) is better at demonstrating brachial plexus involvement and evaluating the spinal canal for tumor extension. MR angiography is better for demonstrating subclavian vessel involvement. Bronchoscopy may be diagnostic for larger tumors, but transthoracic needle aspiration is the most common method of diagnosis of these apical tumors. The usual staging tests include a positron emission computed tomography (PET) scan and MRI of the brain because of the propensity for brain metastases.
The treatment of patients with superior sulcus tumors caused by non–small cell lung cancer with no evidence of mediastinal nodal metastases is initial concurrent chemotherapy and radiotherapy followed by surgical resection 3 to 5 weeks after induction therapy. The 5-year survival with this trimodality treatment is approximately 40%. Patients with documented mediastinal lymph node involvement at initial presentation are treated with deﬁnitive chemoradiotherapy alone with somewhat inferior long-term survival. Patients with stage IV or metastatic disease at presentation are treated with palliative radiotherapy and systemic chemotherapy similar to other patients with stage IV disease.