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Musculoskeletal & Skin Pathology — Step 1 practice questions
69 questions in this area, with an explanation for every answer choice.
Three samples below, free and without an account.
How this shows up on Step 1
Pathology questions in this section combine two things the exam tests separately elsewhere. Pathology is the largest discipline on Step 1. Dermatology is largely pattern recognition from a written description, so the vocabulary of lesion morphology has to be automatic.
Sample questions
Sample question 1
A 3-year-old has 6 days of high fever, bilateral nonexudative conjunctival injection, cracked red lips with a strawberry tongue, a polymorphous truncal rash, erythema and swelling of the hands and feet, and unilateral cervical lymphadenopathy. Which of the following is the most important reason to treat promptly?
Explanations
A. To prevent rheumatic valvular disease with corticosteroids
Rheumatic fever follows streptococcal pharyngitis and is prevented by antibiotics.
B. To prevent renal failure with plasma exchange
Plasma exchange is reserved for refractory cases, not first-line.
C. To prevent hepatic failure with N-acetylcysteine
Hepatic failure is not the concern.
D. To prevent coronary artery aneurysms, using intravenous immunoglobulin and aspirin · correct
Kawasaki disease is a medium-vessel vasculitis of young children. Its danger is coronary artery aneurysm formation in up to a quarter of untreated patients, risking thrombosis, infarction, and sudden death. IVIG plus aspirin within 10 days of fever onset dramatically reduces this risk — one of the few pediatric indications for aspirin despite Reye syndrome concerns. Echocardiography is obtained at diagnosis and in follow-up.
E. To prevent post-streptococcal glomerulonephritis with penicillin
Post-streptococcal disease is unrelated.
Sample question 2
A 68-year-old man is found incidentally to have an isolated markedly elevated alkaline phosphatase with normal calcium, phosphate, and PTH. Which of the following is the most likely diagnosis?
Explanations
A. Paget disease of bone · correct
An isolated, markedly elevated alkaline phosphatase with otherwise normal calcium/phosphate/PTH is the classic laboratory signature of Paget disease of bone, reflecting high bone turnover.
B. Multiple myeloma
Multiple myeloma typically causes hypercalcemia and lytic lesions without primarily elevating alkaline phosphatase.
C. Osteomalacia
Osteomalacia shows low-normal calcium/phosphate with elevated PTH (secondary hyperparathyroidism), not normal calcium/phosphate.
D. Primary hyperparathyroidism
Primary hyperparathyroidism shows elevated calcium and PTH with low phosphate, not normal labs with isolated ALP elevation.
E. Osteoporosis
Osteoporosis shows entirely normal laboratory values (it is a bone quantity problem, not a laboratory-detectable metabolic disturbance).
Sample question 3
A 62-year-old man has years of persistent scaly patches and plaques initially diagnosed as eczema, now with erythroderma, lymphadenopathy, and circulating atypical lymphocytes with cerebriform nuclei. Which of the following is the most likely diagnosis?
Explanations
A. Sezary syndrome, the leukemic variant of cutaneous T-cell lymphoma, with malignant CD4 T cells forming Pautrier microabscesses in the epidermis · correct
Mycosis fungoides is a cutaneous T-cell lymphoma of mature CD4 cells that evolves slowly through patch, plaque, and tumor stages, frequently misdiagnosed as eczema or psoriasis for years. Histology shows epidermotropic atypical lymphocytes forming PAUTRIER microabscesses. SEZARY SYNDROME is the leukemic variant: erythroderma, lymphadenopathy, and circulating Sezary cells with characteristic CEREBRIFORM nuclei. Treatment ranges from topical therapy and phototherapy to systemic agents.
B. Cutaneous B-cell lymphoma
The malignant cells are of T-cell lineage.
C. Psoriasis with erythrodermic flare
Psoriasis shows well-demarcated plaques with silvery scale and no cerebriform cells.
D. Drug-induced erythroderma
Drug erythroderma has a temporal drug relationship without cerebriform cells.
E. Chronic eczema with secondary infection
Eczema does not produce circulating atypical lymphocytes.
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