Image Quizzes

Paresthesias along forearm

Reviewed by Karl J. D'Silva, MD

Medscape

A 54-year-old man presents with shoulder pain and paresthesias along the medial side of the forearm. The patient has a 50–pack-year history of smoking. He reports that the pain began about 6 weeks ago, at which point he scheduled an orthopedic consultation. Physical examination is also notable for facial flushing. Breathing is normal, with no shortness of breath. Chest radiography reveals asymmetry of the apices (right apex is more opaque than the left). Invasion of the ribs is also seen.

What is the likely diagnosis?

Thyroid cancer

Lymphoma

Non–small cell lung cancer, Pancoast tumor

Adenoid cystic carcinoma

On the basis of this presentation, and the findings from the chest x-ray (as shown), the likely diagnosis is non–small cell lung cancer (NSCLC), Pancoast tumor, also known as superior sulcus tumor. Pancoast tumors are rare, representing about 3%-5% of all lung cancers, and invade the structures in the apex of the chest, including the first thoracic ribs or periosteum, the lower nerve roots of the bronchial plexus, the sympathetic chain and stellate ganglion, or the subclavian vessels. The majority of Pancoast tumors are non–small cell carcinomas.

Because of their pulmonary location, Pancoast tumors are characterized by several distinct symptoms. As seen in this case, patients often present with shoulder pain that worsens over time, especially with invasion of the chest wall and brachial plexus. The pain may radiate to the neck; axilla; anterior chest wall; and medial aspect of the arm, forearm, and wrist. If Pancoast tumors infiltrate the ulnar nerve, patients may present with weakness and muscle atrophy of the intrinsic muscles of the hand. In addition, invasion of the sympathetic chain and of the inferior cervical ganglion can cause Horner syndrome (ptosis, miosis, enophthalmos, and anhidrosis). Lastly, upper-arm edema may develop, signaling invasion and potentially occlusion of the subclavian vein.

During workup, CT-guided core biopsy is the first-line diagnostic test for Pancoast tumors. CT of the chest can confirm the presence of an apical mass and its position in relation to other structures of the thoracic inlet. MRI can further assess suspected brachial plexus, subclavian vessels, spine, and neural foramina invasion, specifying the extent of the disease and of the amount of nerve-root involvement.

For resectable Pancoast tumors, the National Comprehensive Cancer Network recommends chemoradiation, followed by surgical resection and chemotherapy. Preoperative chemoradiation together with surgical resection has shown a 2-year survival between 50% and 70%. Depending on biomarker status (certain EGFR mutations or programmed death ligand 1 levels ≥ 1%), the addition of either atezolizumab or osimertinib is advised. However, the positioning of Pancoast tumors can pose a surgical challenge, and if the lesion remains unresectable after preoperative concurrent chemoradiation, then consolidation immunotherapy with durvalumab is recommended.

Karl J. D'Silva, MD, Clinical Assistant Professor, Department of Medicine, Tufts University School of Medicine, Boston; Medical Director, Department of Oncology and Hematology, Lahey Hospital and Medical Center, Peabody, Massachusetts.

Karl J. D'Silva, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

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