Case Series of Three Cases of Madura’s Foot with a Characteristic ‘Dot in Circle’ Sign: A Radiologist Perspective

Abstract

Madura’s foot is a rare infectious granulomatous disease affecting the foot. The incidence of this disease has decreased in recent years due to improved living conditions. However, it can still be misdiagnosed by inexperienced surgeons as other similar conditions. Early and accurate diagnosis is crucial for optimal treatment and limb preservation. In this study, the authors present three unusual cases of Madura’s foot. A 23-year-old woman presented with swelling and draining sinuses in her left foot for six years. Imaging tests including Ultrasonography (USG), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI) revealed the characteristic ‘dot in circle’ sign of Madura’s foot. However, her USG-guided biopsy did not confirm the diagnosis, and it was only through an excisional biopsy that actinomycetoma was confirmed. Another case involved a 60-year-old male with multiple soft tissue swellings on his right foot for 10 years, resulting in foot deformity. Radiographs showed multiple punched-out lytic lesions in the bones, while USG and MRI exhibited the typical ‘dot in a circle’ sign. Histopathological examination confirmed actinomycetoma. The third case involved a 36-year-old male with a chronic sinus discharging yellow pus and black granules on the volar side of his right foot. USG and MRI revealed the classic signs of Madura’s foot, and these findings were correlated with histopathological examination. The present cases confirm the specificity of the ‘dot-in-circle’ sign on MRI and USG, supported by histopathological correlation.