I will answer the sample USMLE Step 2 CK Questions with Explanations. These questions are available at USMLE.org
Q- A 50-year-old man comes to the office for a health maintenance examination. He says he has felt well and reports no symptoms. Medical history is unremarkable. He takes no medications. He uses up to three cans of chewing tobacco weekly and occasionally sleeps with tobacco in his mouth. He says he would like to quit but cannot seem to do it on his own. Vital signs are within normal limits. Examination shows a whitish discoloration that measures approximately 1 cm in diameter on the buccal mucosa. The tongue has a brownish discoloration. Palpation of the neck discloses no lymphadenopathy. In addition to encouraging the patient to quit using chewing tobacco, which of the following is the most appropriate next step in management?
(A) Prescribing oral nystatin suspension
(B) Surgical biopsy of the oral lesion
(C) Swabbing of the white area and sending for cytology
(D) Observation only
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Answer
The patient in this case presents with a whitish discoloration on the buccal mucosa, which is concerning for leukoplakia. Leukoplakia is a premalignant lesion that is often associated with tobacco use, especially chewing tobacco. It appears as a white patch or plaque that cannot be easily scraped off. Since the patient uses tobacco and the lesion is persistent, this raises concern for possible transformation into oral squamous cell carcinoma.
In this context, the most appropriate next step is:
(B) Surgical biopsy of the oral lesion
A biopsy is essential to rule out dysplasia or malignancy, especially in a patient with a significant history of tobacco use. Observation without further evaluation could delay the diagnosis of a potentially serious condition.
- (A) Prescribing oral nystatin suspension would be appropriate if the lesion were caused by a fungal infection like candidiasis, but that typically presents as a white lesion that can be scraped off, unlike leukoplakia.
- (C) Swabbing of the white area and sending for cytology is not as definitive as a biopsy for evaluating potential premalignant or malignant lesions in the oral cavity.
- (D) Observation only would not be appropriate given the potential for oral cancer in a patient with this history of tobacco use.
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