What are the typical symptoms of a Pancoast tumor?

Symptoms of Pancoast Tumors

Pancoast tumors typically present with a characteristic syndrome of shoulder and arm pain, Horner syndrome, and weakness/paresthesias in the distribution of the C8 and T1-T2 nerve roots due to invasion of the brachial plexus and adjacent structures at the thoracic inlet. 1, 2

Classic Symptoms and Signs

Pain

• Shoulder and arm pain (most common presenting symptom)
  • Radiates along the ulnar distribution of the upper arm
  • Often severe and unrelenting
  • May be initially dismissed as musculoskeletal in origin 3, 4

Neurological Symptoms

• Weakness and atrophy of hand and arm muscles
• Paresthesias in C8-T1-T2 distribution
• Pain and neurological deficits due to invasion of:
  • Brachial plexus (particularly lower trunk)
  • C8, T1, and T2 nerve roots 1, 2

Horner Syndrome

• Complete syndrome includes:
  • Ptosis (drooping eyelid)
  • Miosis (constricted pupil)
  • Anhidrosis (lack of facial sweating)
• Results from invasion of the sympathetic chain and stellate ganglion 1

Less Common Presentations

• Chest wall pain from direct invasion of ribs and soft tissues
• Dysphagia if mediastinal spread occurs
• Subclavian vein obstruction causing upper extremity edema
• Hoarseness (rare, from recurrent laryngeal nerve involvement)
• Vertebral pain if tumor extends to vertebral bodies 1, 2, 3

Important Clinical Considerations

1. Delayed Diagnosis: The distribution of symptoms outside the chest often delays consideration of lung cancer as the primary etiology 1

2. Risk Factors: Most patients have significant smoking history (typically >50 pack-years) 4

3. Respiratory Symptoms: Often absent due to the peripheral location of the tumor 1

4. Progression: Without treatment, patients typically experience severe, unrelenting arm pain making this one of the most distressing forms of lung cancer 1

5. Differential Diagnosis: Can be mistaken for:

   • Cervical disc disease
   • Brachial plexopathy from other causes
   • Shoulder pathology
   • Thoracic outlet syndrome 4

Diagnostic Approach for Suspected Pancoast Tumor

When a patient presents with the characteristic symptoms:

1. Imaging:

   • Chest CT scan (essential initial test)
   • MRI of thoracic inlet/brachial plexus (superior for evaluating invasion of apical chest wall structures) 2
   • Plain radiographs may show apical pleural thickening but can miss tumors hidden behind the first rib 2

2. Tissue Diagnosis:

   • CT-guided needle biopsy is preferred
   • Histologic confirmation is mandatory before treatment 2

Red Flags Suggesting Pancoast Tumor

• Persistent shoulder/arm pain unresponsive to conventional treatments
• Pain with neurological symptoms in C8-T1 distribution
• Horner syndrome
• History of smoking
• Weight loss or other constitutional symptoms 3, 4

The distribution of symptoms outside the chest and the absence of respiratory symptoms often lead to delayed diagnosis of Pancoast tumors. Clinicians should maintain a high index of suspicion in patients with persistent upper extremity pain, especially those with risk factors for lung cancer.