Madura foot masquerading as a hemangioma

Abstract

Mycetoma, also known as Madura foot, is a rare soft-tissue granulomatous infection caused by Actinomyces or true fungi. The MRI "dot-in-circle" sign has been described as a characteristic finding of mycetoma. This sign represents spherical T2 bright masses containing central and intervening low-signal-intensity foci. However, other soft-tissue masses can have similar appearances. We present a case of a Madura foot that was erroneously given the imaging diagnosis of soft-tissue hemangioma due to the presence of serpiginous enhancing masses with the "dot-in-circle" sign (believed to be due to phleboliths).

Keywords: CT, computed tomography; MRI, magnetic resonance imaging.

Figure 1

Axial T1 image of the foot demonstrating round and serpiginous intermediate-signal-intensity masses in the lateral subcutaneous tissues, Some of the masses have internal areas of low T1 signal.

Figure 2

Axial STIR image demonstrates the “dot-in-circle” sign described in mycetoma (arrow).

Figure 3

Axial T1 fat-suppressed image, post contrast, demonstrates enhancement of the mass involving the lateral soft tissues of the foot and “dot-in-circle” sign (arrow).

Figure 4

Sagittal T1 fat-suppressed postgadolinium image at the lateral aspect of the ankle and foot demonstrates a large enhancing mass containing spherical and serpiginous components that contain both central and intervening areas of low signal.