Benign multicystic mesothelioma masquerading as a urachal cyst.

Benign multicystic mesothelioma (BMM) is a benign intra-abdominal lesion that generally occurs in women in their reproductive years. A urachal cyst occurs when the epithelial-lined urachal canal fails to completely obliterate. We report a case of a 38-year-old female presenting with abdominal pain found to have a lesion highly suspicious for a urachal cyst. On pathologic evaluation the lesion was identified as a BMM. This is the first report of BMM presenting as a lesion suspected to be a urachal cyst.