Apical Lung Mass with Bony Destruction of the First Rib
The imaging finding most consistent with this presentation is an apical lung mass with bony destruction of the first rib, which represents a Pancoast tumor (superior sulcus tumor) causing the classic Pancoast-Tobias syndrome. 1
Clinical Presentation Analysis
This patient presents with the pathognomonic triad of Pancoast syndrome:
- Horner syndrome (left-sided ptosis and miosis) resulting from invasion of the stellate ganglion and sympathetic chain 1
- Shoulder and arm pain radiating down the arm from invasion of the brachial plexus and adjacent soft tissues 1
- Progressive weakness and muscle atrophy in the left hand from invasion of the lower brachial plexus (C8-T1 nerve roots), presenting with neurologic findings in the ulnar distribution 1
The 35 pack-year smoking history significantly elevates her risk for lung cancer, making this clinical constellation highly specific for a superior sulcus tumor. 1, 2
Why Apical Mass with Bony Destruction is Correct
A Pancoast tumor is formally defined as a lung cancer arising in the apex of the lung that involves structures of the apical chest wall at the level of the first rib or above. 1 The tumor is classified as:
- T3 if it involves the T1 or T2 nerve roots or first rib 1
- T4 if there is involvement of C8 or higher nerve roots, cords of the brachial plexus, subclavian vessels, vertebral bodies, or lamina 1
Given this patient's complete Pancoast-Tobias syndrome with Horner syndrome (indicating stellate ganglion invasion) and hand weakness (indicating C8-T1 nerve root involvement), this represents at minimum a T3 tumor with first rib involvement, and likely T4 disease. 1, 3, 4
Posteroanterior and lateral chest radiographs may demonstrate nothing more than apical pleural thickening because tumors can hide behind the first rib, but bony destruction of the first rib is a characteristic finding when visible. 1
Why Other Options Are Incorrect
Bilateral hilar lymphadenopathy: This would suggest sarcoidosis, lymphoma, or metastatic disease, but would not explain the unilateral Horner syndrome or the specific C8-T1 distribution of neurologic deficits 1
Large central mass obstructing the mainstem bronchus: This would present with respiratory distress, wheezing, or post-obstructive pneumonia—none of which are present in this patient 1
Multiple diffuse pulmonary nodules: This suggests metastatic disease or miliary infection, which would not cause the localized apical chest wall invasion necessary for Pancoast syndrome 3
Pneumothorax: This would present with acute respiratory distress and would not explain the progressive neurologic symptoms or Horner syndrome 1
Critical Diagnostic Pitfall
The most common diagnostic error is attributing shoulder pain and arm weakness to musculoskeletal or cervical spine pathology (radiculopathy), delaying the diagnosis of Pancoast tumor. 2 This patient's presentation could easily be misdiagnosed as cervical radiculopathy or rotator cuff pathology, but the combination of Horner syndrome with the neurologic findings makes Pancoast tumor the only diagnosis that explains all features. 2, 4
Next Steps in Management
Once imaging confirms the apical mass with chest wall invasion:
- Obtain tissue diagnosis via CT-guided transcutaneous needle biopsy before initiating treatment 1
- Perform both chest CT and MRI to assess resectability—MRI demonstrates involvement of apical chest wall structures (brachial plexus, subclavian vessels) better than CT 1
- Invasive mediastinal staging should be performed in all patients being considered for curative resection, regardless of CT or PET findings 1
- The majority of Pancoast tumors are adenocarcinomas (approximately 2/3), with the remainder being squamous cell and large cell carcinomas 3