Introduction
Osteosarcoma is commonest primary malignant bone tumor of unintelligible origin, with peak age at 10-19 years old(1). The distal radius is a rare site for osteosarcoma; it was reported less than <1% (2). Between all the bone tumors, osteosarcoma have the widest variety in clinical presentation, imaging findings, morphological and histological features. The mainstream treatment is combination of chemotherapy and surgical treatment which improved the overall prognosis in the last two decades (3-4). However, mycetoma is a chronic cutaneous and subcutaneous painless swelling caused by two major types of pathogens, either bacterial type (actinomycotic) or fungus type (eumycotic) [5]. It is the most common neglected disease of human in tropical and subtropical areas among low socioeconomic individuals [5,6]. It involves the skin and connective tissue. Painless destructive nature, late presentation, poor response to treatment and high recurrence rate are characteristic features of this disease. Among all the endemic countries, Sudan have the highest incidence [6-8]. The chronic inflammatory granuloma, various deformaties, disabilities and high morbidity rate are the commonest known complications of mycetoma, the disease can be potentially limb threatening in its late stage [9,10]. Clinically, mycetoma starts as a small painless lump which increase in size gradually, forming multiple sinuses with seropurulent discharge and eventually multicolored grains appear [11]. Meticulous Clinical assessment , radiological and histopathological analysis of such lesion is important for a presice diagnosis and management, especially when dealing with unclear osteo-articular lesion. Management of mycetoma predominantly depends on the etiological agent, site and extent of the disease [12]. This case review serves to exemplify the importance of recognizing the similarities between these 2 lesions and other rare features that will help differentiate between osteosarcoma and mycetoma, also to highlight and demonstrate the destructive features of bone involvement by mycetoma that usually associate with inadequate assessment, and the impact of delayed presentation or late diagnosis to the overall outcome.