Lymphoma is the seventh most common type of malignancy in both males and females. It may develop in any location where lymphomatous tissue exists. Although extranodal presentation in the lower limb and pelvis are uncommon, it could present with diverse manifestations. We report an unusual case of primary extranodal large B-cell lymphoma of the ankle joint initially presumed to be a chronic osteomyelitis. This case report discusses the impact of imaging studies on decision-making and highlights the need to consider malignancy in chronic infections.