Granulocytic sarcoma masses are commonly seen in which type of the following malignancies?

Correct Answer: D

Rationale: Granulocytic sarcoma is most commonly associated with acute myeloid leukemia (AML).

Correct Answer: B

Rationale: Recognizable external genitalia are formed by 14 weeks, not 12 weeks.

Correct Answer: D

Rationale: Primary mediastinal involvement is a hallmark feature of ALCL.

Correct Answer: C

Rationale: Pyelonephritis is a bacterial infection of the kidney. One of the key indicators of pyelonephritis is the presence of pyuria, which refers to white blood cells in the urine. White blood cells in the urine suggest inflammation and infection in the urinary tract, particularly in the kidneys. Therefore, the presence of pyuria supports a diagnosis of pyelonephritis. Myoglobinuria (choice A) is the presence of myoglobin in the urine and is associated with muscle breakdown, not specifically with pyelonephritis. Ketonuria (choice B) refers to the presence of ketones in the urine and may be seen in conditions such as diabetic ketoacidosis. A low white blood cell count (choice D) is not typically associated with pyelonephritis, as an infection would generally result in an elevated white blood cell count in response to the infection.

Correct Answer: A

Rationale: Respiratory distress syndrome is primarily caused by deficient surfactant production in premature infants. Surfactant is a substance that coats the alveoli in the lungs and helps to reduce surface tension, preventing the collapse of the alveoli during exhalation. In premature infants, the lungs may not have produced enough surfactant, leading to difficulty in breathing and inadequate oxygen exchange. This results in respiratory distress syndrome, which is characterized by severe breathing problems in newborns. Overproduction of surfactant, overdeveloped alveoli, or absence of alveoli are not central factors in the development of respiratory distress syndrome.