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By Muhammad Waseem, MD
09.10.09

A 4-year-old boy was brought to the emergency department with abdominal pain. He has a prior history of constipation and was taking stool softener. His vital signs were stable. The abdominal examination revealed a large mass in the left side of his abdomen. The mass was firm and slightly tender. A CT scan of abdomen was obtained.

What is your diagnosis?

The answer and explanation to Mystery Case 16 will not be revealed until a reader posts a correct answer to the case.