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Difficulty: MediumRheumatology and Immunology

A 54-year-old woman comes to the clinic reporting a 2-month history of progressive weakness, particularly when climbing stairs and brushing her hair. She also notes a new rash on her face and hands. Her medical history is unremarkable, and she takes no medications. Physical examination reveals an erythematous, violaceous rash on her upper eyelids and scaling, erythematous plaques over her metacarpophalangeal and proximal interphalangeal joints. Muscle strength is 3/5 in the proximal upper and lower extremities bilaterally, and 5/5 in the distal extremities. Sensation is intact, and deep tendon reflexes are 2+ bilaterally.

Laboratory results show:
TestResultReference Range
Creatine kinase4,500 U/L30-170 U/L
Thyroid-stimulating hormone2.1 mU/L0.5-5.0 mU/L
Free T41.2 ng/dL0.9-1.7 ng/dL
Antinuclear antibodiesPositiveNegative

The physician diagnoses the patient with dermatomyositis and plans to initiate high-dose oral prednisone. Which of the following is the most appropriate additional step in the management of this patient?

  1. A
    Administration of broad-spectrum antibiotics
  2. B
    Administration of the live-attenuated influenza vaccine
  3. Screening for an underlying malignancyAnswer
  4. D
    Initiation of levothyroxine therapy
  5. E
    Reassurance regarding the benign nature of the skin findings

Answer

Screening for an underlying malignancy
The correct answer highlights the strong association between adult-onset dermatomyositis and occult malignancy. Approximately 15% to 25% of adult patients with this autoimmune inflammatory myopathy have an underlying cancer, most commonly involving the ovaries, lungs, pancreas, stomach, or colon. Therefore, comprehensive evaluation must include age-appropriate cancer screening (e.g., colonoscopy, mammography, pelvic examinations) in addition to initiating immunosuppressive therapy such as high-dose glucocorticoids.

Step-by-Step Solution

1
Analyze the clinical presentation.
The patient has progressive proximal muscle weakness, a heliotrope rash (violaceous rash on upper eyelids), and Gottron papules (erythematous plaques over MCP and PIP joints), alongside elevated creatine kinase.
To establish the diagnosis of dermatomyositis.
2
Identify the known disease associations with this diagnosis in adult patients.
Adult-onset dermatomyositis is strongly associated with underlying occult malignancies (e.g., ovarian, lung, pancreatic, stomach, and colorectal cancers).
To determine the necessary comprehensive evaluation steps beyond symptomatic treatment.
3
Select the appropriate additional management step.
Age-appropriate screening for an underlying malignancy is required.
Because identifying a potential underlying paraneoplastic trigger is critical for patient survival and overall management.

Key Concept

Adult patients with newly diagnosed dermatomyositis have a significantly increased risk of concurrent malignancy and should undergo age-appropriate cancer screening.
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Topics

Rheumatology and Immunology

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