Lyme Disease Presenting as Rupture Baker's Cyst: Case Report and Literature Review.

Baker's cysts, also known as popliteal cysts, are fluid-filled sacs that are found in the posterior region of the knee, behind the medial head of the gastrocnemius and the semimembranosus. The prevalence has been found to increase with age, with some ultrasonographic studies showing a prevalence as high as 25% of adults with knee pain. We discuss an interesting case of a 14-year- old male with a ruptured cyst found to be secondary to Lyme disease. The patient was treated with clindamycin and his symptoms had resolved. We discuss cases of ruptured baker's cysts in the literature found to be secondary to Lyme disease with their respective treatments and outcomes.