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.
