Clinical Context
This patient presents with dermatomyositis (DM) — evidenced by proximal muscle weakness, elevated CK, and anti-Jo-1 antibody positivity — in the setting of a lung mass on imaging.
Key Pathophysiology
Key Point
Dermatomyositis is a paraneoplastic syndrome associated with underlying malignancy in 10–50% of adult cases, particularly lung cancer. The presence of a lung mass on imaging in a patient with newly diagnosed DM is a red flag for occult malignancy.
Management Algorithm
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Rationale for Correct Answer
- 1.
Concurrent dual management: Corticosteroids address the inflammatory myositis, while urgent lung cancer staging and biopsy confirm malignancy and guide oncologic therapy.
- 2.
Timing is critical: Paraneoplastic DM often improves with treatment of the underlying cancer; delaying cancer diagnosis worsens prognosis.
- 3.
Anti-Jo-1 positivity is associated with interstitial lung disease and is a strong predictor of malignancy-associated myositis.
High-Yield Facts
High-YieldNEET PG
In any adult presenting with dermatomyositis, particularly with anti-synthetase antibodies (Jo-1, PL-7, EJ), a thorough malignancy screen (CT chest/abdomen, age-appropriate cancer screening) is mandatory before attributing symptoms solely to autoimmunity.
Clinical Pearl
The presence of a lung mass on imaging in a DM patient is NOT incidental — it must be biopsied and staged urgently, as treatment of the underlying cancer often leads to remission of myositis.
