#1. A 31-year-old woman presented with fever following a trip to Brazil. What diagnosis is suggested by the findings on her blood smear?

The presence of a ring form and basophilic stippling within the red cell accompanied by serpentine forms suggest Plasmodium vivax as the responsible organism.

#2. What diagnosis explains this 15-year-old patient's chest pain?

The chest radiograph shows clear lungs, pneumomediastinum and pneumopericardium without evidence of rib fracture or pneumothorax.

#3. Twelve hours after urgent coronary angiography, the appearance of this patient's feet had changed. What is the most likely explanation for the finding?

The bluish discoloration of the toes with livedo reticularis that appeared after coronary angiography suggests a diagnosis of cholesterol emboli.

#4. A 55-year-old man underwent colonoscopy after complaining of crampy lower abdominal pain. Mobile 1-cm worms were noted in cecum. What is the most likely diagnosis?

These 1-cm cecal worms are most consistent with Enterobius vermicularis (pinworm).

#5. This abnormality was found during auditory screening of a five-year-old girl at school. What is the most likely diagnosis?

A cholesteatoma medial to an intact translucent tympanic membrane is shown in the left ear of this five-year-old girl.

#6. This 36-year-old man has undergone renal transplantation and parathyroidectomy. What is the most likely cause of the changes in his hands?

The history and preservation of the nail fold angle suggest pseudoclubbing as the diagnosis, a change that results from soft-tissue collapse due to severe bony erosions.

#7. This 46-year-old woman developed pruritus and similar papular lesions over her axillae, groin, and buttocks. What is the most likely diagnosis?

These lesions were caused by bird mite, and are similar to the lesions caused by scabies.

#8. This 63-year-old man with a 10-year history of progressive neck enlargement noted a sudden increase in the size of the swelling on the left side. What is the most likely diagnosis?

An acute hematoma into an established multinodular goiter caused the acute swelling.

#9. A 39-year-old Zambian man who has tested positive for the human immunodeficiency virus presented with a three-week history of a draining neck mass. What is the most likely diagnosis?

The patient was found to have scrofula (tuberculous lymphadenitis in the cervical region). Scrofula presents as a chronic, nontender lymphadenopathy, which may fistulize and drain cutaneously.

#10. What is the most likely cause of the abnormality on the chest radiograph?

Unilateral pulmonary edema and the presence of a chest tube in the right thorax suggest reexpansion pulmonary edema as the diagnosis.