From a Radiologist’s Eye: a Case Report of Actinomycetoma of the Foot With Comprehensive Review of Literature

Abstract

Background: Tropical diseases comprise of an array of communicable and non-communicable diseases that prevail in the tropical belt. Madura foot, classified as a tropical disease by WHO, is a chronic granulomatous disease that predominantly involves the skin and subcutaneous tissue, commonly affecting the lower limbs. We present a case of actinomycetoma with extensive review of the existing literature, focusing on diagnostic imaging. Case presentation: A 36-year-old female from eastern India presented with a six-month history of right foot swelling and a discharging wound. She was unsuccessfully treated with multiple courses of antibiotics in local hospitals. Upon referral, radiological investigations were performed for further evaluation. USG showed infiltrative hypoechoic soft tissue with nodular lesions showing targetoid appearance. MRI revealed infiltrative soft tissue with variable sized nodular lesion showing characteristic ‘dot-in-circle' appearance, prompting the diagnosis of pedal mycetoma. Actinomycetoma was confirmed on biopsy. Conclusions: Pedal mycetoma presents significant diagnostic and therapeutic challenges owing to its insidious progression and delayed diagnosis. Radiological imaging, particularly MRI, plays a pivotal role in diagnosis and staging of the disease, enabling detailed evaluation of soft tissue and bone involvement. The ‘dot-in-circle' sign observed on imaging is pathognomic and aids in accurate diagnosis. Early diagnosis facilitated by diagnostic imaging warrants improved therapeutic outcomes.