Question

A 45-year-old patient presents with ptosis and muscle weakness that improves with rest. She also complains of dysphagia and has engorged veins in her thorax. Based on the CT scan image provided, what is the most likely diagnosis? 

• A. Thymoma
• B. Pancoast tumor
• C. Adenocarcinoma
• D. Small cell lung cancer

Hint:

When a patient presents with ptosis, muscle weakness, and dysphagia along with chest imaging abnormalities, consider thymoma as a potential cause, especially in the context of myasthenia gravis.

Answer 1

The Correct Option is A

Answer: Thymoma.

Solve this by joining three findings to one place in the chest: the anterior (front) mediastinum.

First, the muscle weakness and drooping eyelids (ptosis) that get better with rest are the signature of myasthenia gravis. This happens when the body makes antibodies against acetylcholine receptors at the muscle. Myasthenia gravis is strongly linked to a tumour of the thymus gland, called a thymoma.

Second, the swallowing trouble (dysphagia) and the swollen veins over the chest suggest the mass is pressing on nearby structures, including the superior vena cava. The thymus sits in the anterior mediastinum, exactly where such a mass would press.

The common anterior mediastinal masses are remembered as the 4 T's: Thymoma, Teratoma, Thyroid (retrosternal), and Terrible lymphoma. Of these, only thymoma explains the myasthenia gravis.

The other options do not fit:
- Pancoast tumour sits at the top of the lung and causes Horner syndrome and arm pain, not myasthenia.
- Adenocarcinoma and small cell lung cancer arise in the lung, not the thymus. Small cell cancer is instead linked to Lambert-Eaton syndrome, where weakness improves with activity rather than rest, which is the opposite of this patient.

The anterior mass plus myasthenia gravis points to thymoma (option 1).