is the most common site of extra-pulmonary involvement by tuberculosis, tuberculous infection of the scrotum is rare and occurs in approximately 7% of patients with tuberculosis. At the initial stage of infection, the epididymis alone is involved. However, if appropriate antituberculous treatment is not administered promptly, the infection will spread to the ipsilateral testis. The occurrence of isolated testicular tuberculosis is rare. Clinically patients with tuberculous epididymo-orchitis may present with painful or painless enlargement of the scrotum, hence they cannot be distinguished from lesions such as testicular tumor, testicular infarction and may mimic testicular torsion. At ultrasound, tuberculous epididymitis is characterized by an enlarged epididymis with variable echogenicity. The presence of calcification, caseation necrosis, granulomas and fibrosis can result in heterogeneous echogenicity [Fig. 21a]. The ultrasound findings of tuberculous orchitis are as follow: (a) diffusely enlarged heterogeneously hypoechoic testis (b) diffusely enlarged homogeneously hypoechoic testis (c) nodular enlarged heterogeneously hypoechoic testis and (d) presence of multiple small hypoechoic nodules in an enlarged testis [Fig. 21b]. Although both bacterial and tuberculous infections may involve both the epididymis and the testes, an enlarged epididymis with heterogeneously hypoechoic pattern favors a diagnosis of tuberculosis (Muttarak and Peh, 2006, as cited in Kim et al., 1993 and Chung et al., 1997). With color Doppler ultrasound, a diffuse increased blood flow pattern is seen in bacterial epididymitis, whereas focal linear or spotty blood flow signals are seen in the peripheral zone of the affected epididymis in patients with tuberculosis. Fournier gangrene Fournier gangrene is a polymicrobial necrotizing fasciitis involving the perineal, perianal, or genital regions and constitutes a true surgical emergency with a potentially high mortality rate. It usually develops from a perineal or genitourinary infection but can arise following local trauma with secondary infection of the wound. 40–60% of patients are being diabetic. Although the diagnosis of Fournier gangrene is often made clinically, diagnostic imaging is useful in ambiguous cases. The sonographic hallmark of Fournier gangrene is presence of subcutaneous gas within the thickened scrotal wall. At ultrasound, the gas appears as numerous, discrete, hyperechoic foci with reverberation artifacts [Fig. 22]. Evidence of gas within the scrotal wall may be seen prior to clinical crepitus. The only other condition manifesting with gas at sonographic examination is an inguinoscrotal hernia. This can be differentiated from Fournier gangrene by the presence of gas within the protruding bowel lumen and away from the scrotal wall. (Levenson et