Reshma Mathen, MD, Weill Cornell Medical Center, New York-Presbyterian Hospital, New York, NY
A 50-year-old woman presents with abdominal complaints and weight loss.
What is the most likely diagnosis?
You are correct!
Low attenuation retroperitoneal adenopathy. Miliary nodules in the upper and lower lobes of the lungs.
The differential diagnosis of retroperitoneal adenopathy is wide and varied. Categories to consider include neoplastic etiologies such as metastatic adenopathy and lymphoma, infectious etiologies, such as fungal disease, HIV, and tuberculosis (TB), and inflammatory etiologies, such as sarcoidosis and Castleman’s disease.
The attenuation of adenopathy may narrow the differential diagnosis. Hyperenhancing nodes are seen with Castleman’s disease, whereas low attenuation nodes may be seen with necrotic adenopathy and TB. Treated lymphoma also may be low in attenuation.
As per the World Health Organization, there were 8.8 million new cases of TB diagnosed in 2010, and 1.45 million deaths, most of these occurring in developing countries. While the majority of active disease involves the pulmonary system, 15% to 25% of cases may be extrapulmonary, manifesting as meningitis, genitourinary disease or osteomyelitis. Abdominal TB, which may involve the gastrointestinal tract, peritoneum, lymph nodes or solid viscera, constitutes up to 12% of extrapulmonary TB. Most commonly, abdominal TB involves the gastrointestinal tract, typically affecting the terminal ileum, where TB granulomas form in the mucosa or the Peyer’s patches. On CT, there may be diffuse bowel wall thickening with or without stricture formation. In later stages of disease, adherent loops, mesenteric thickening and regional lymph nodes may produce a mass-like appearance centered at the terminal ileum. Complications of perforation, abscess, and obstruction can also be seen.
Only a minority of abdominal TB will have concurrent pulmonary findings, making TB an important consideration when evaluating imaging studies in patients with risk factors for the disease. Including this entity in the differential may avoid unnecessary treatment delay.