Case report: Dot-in-circle sign - An MRI and USG sign for "Madura foot"

Abstract

Mycetoma is a chronic granulomatous disease that is more common in tropical than in temperate regions. Early diagnosis is important due to the therapeutic implications. Although biopsy and microbiological culture provide definitive diagnosis, they are time-consuming procedures and may not be able to provide a definite diagnosis in cases of fastidious organisms. The “dot-in-circle” sign has recently been proposed as a highly specific magnetic resonance imaging (MRI) and ultrasonography (USG) sign of mycetoma, which may allow a noninvasive as well as early diagnosis. We present a case of histologically proven mycetoma that demonstrated this sign.