Increased through-transmission in abdominal tuberculous lymphadenitis.

Objective: To describe 2 cases of abdominal tuberculosis in which sonographic evaluation of mesenteric lymphadenopathy showed increased through-transmission suggestive of caseating necrosis.

Methods: Two patients with abdominal pain and other symptoms (including fever, diarrhea, and weight loss) underwent abdominal sonography with a 6-MHz curved array transducer. One patient also underwent sonographically guided fine-needle aspiration of multiple lymph nodes, and the other underwent computed tomography, colonoscopy, and colon biopsy.

Results: In both patients, sonography showed multiple rounded hypoechoic lesions with increased ultrasound through-transmission suggestive of necrotic lymphadenopathy. No color flow was shown. In 1 case, the posterior acoustic enhancement was accentuated in the harmonic imaging mode. In the other case, the lesions shown on sonography corresponded to computed tomographic findings of low-density lymph nodes. Results of fine-needle aspiration and colon biopsy were positive for tuberculosis.

Conclusions: Posterior acoustic enhancement in abdominal lymphadenopathy can suggest the diagnosis of tuberculous lymphadenitis. Detection of this finding is facilitated by scanning in the harmonic mode. Necrotic nodes will lack color flow and can be distinguished from lymphadenopathy of other causes. Sonography can also be used for fine-needle aspiration of necrotic nodes to yield a definitive diagnosis.