Parasite Wonders: What’s that in her foot?

This week's case involves a previously healthy toddler who began acting unusually fussy and refused to walk. Examination revealed a thin black object under the skin of her right foot. Extraction was unsuccessful, but the child was playing and walking at the end of the visit, and, so, she was sent home. The child was brought back the following day, because the object had moved approximately 3 centimeters within a 24-hour period in the crescent-shaped pattern shown in the image above. At this point, the object was removed and sent to the lab. Based on the clinical image alone, what is it?

Every week, Mayo Clinic microbiologist Dr. Bobbi Pritt posts a new case, along with the answer to the previous case. Read Dr. Pritt's blog, Creepy, Dreadful, Wonderful Parasites, and submit your answers, comments and questions. Learn more about Dr. Pritt's work, and enjoy science!

Note from Dr. Pritt: All opinions expressed here are mine and not my employer's. Information provided here is for medical education only. It is not intended as, and does not substitute for, medical advice. I do not accept medical consults from patients.