CASE 10487 Published on 16.11.2012

Tuberculous peritonitis

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Magalhães Maria, Oliveira Pedro, Fernandes Catarina, Duarte Hálio, Abreu Joana, Malheiro Leonor, Gouvêa Margarida

Email:mariapinheiromagalhaes@hotmail.com
Patient

50 years, female

Categories
Area of Interest Abdomen, Thorax ; Imaging Technique PET-CT, CT
Clinical History
The patient presented an insidious epigastric pain, without fever, weight loss or other signs/symptoms. Past medical history included smoking (18-45years) and cervical lymphadenitis (at the age of 19). Ultrasound was performed and showed a peripancreatic cystic mass, thus the patient was referred to our institution with the suspicion of a pancreatic tumour.
Imaging Findings
18F-FDG PET-CT showed increased FDG uptake in the peripancreatic region, as well as in the surrounding lymph nodes, subcapsular liver and pouch of Douglas. (Fig. 1)
Abdominal Computed Tomography (CT) revealed enlarged lymph nodes, especially in the hepatogastric ligament, featuring hypoattenuating centre. (Fig. 2) The pancreatic parenchyma was homogeneous, without nodules/masses. There was also a diffuse peritoneal thickening with associated enhancement after intravenous contrast administration, and a small amount of peri-hepatic fluid, as well as along the right paracolic gutter and between small bowel loops. (Fig. 3) A small volume of pleural effusion on the right was also identified.
Chest radiograph showed obliteration of the costophrenic angles (right hemithorax), with no other associated finding. (Fig. 4)
Lymphadenopathy biopsy was performed.
Discussion
Tuberculosis has shown a resurgence in nonendemic areas in recent years, particularly in immigrant population and in immunocompromised patients, who have a higher prevalence of extrapulmonary involvement. Indeed, tuberculosis is usually confined clinically to the respiratory system, however, the disease can affect any organ system. [1] In the abdomen, tuberculosis can involve lymph nodes (the most common manifestation of abdominal disease), peritoneum, gastrointestinal tract and solid viscera. [2] Abdominal lymphadenopathy has a typical pattern - mesenteric and peripancreatic lymph node enlargement, with multiple groups involved simultaneously. A characteristic finding is a hypoattenuating centre and enhancing rims after intravenous contrast administration, suggesting caseous necrosis. With respect to tuberculous peritonitis, it can be classically divided into three main types, with an overlap in their CT appearence: Wet, Fibrotic and Dry/Plastic. [1, 2] The first one is the most common, and presents a variable amount of ascites, free or loculated, usually slightly hyperatenuatting due to the high cellular content; fibrotic peritonitis manifests as low-attenuation cake-like masses in the omentum and mesentery; and finally, the least common dry type is characterised by mesenteric thickening, fibrous adhesions and caseous nodules. [1, 2]
The differential diagnosis of abdominal lymphadenopathy is embracing, however, the characteristic finding of hypoattenuating centre lymph nodes associated with diffuse peritoneal thickening and enhancement, and ascites decreases the diagnostic hypotheses. One of the differential diagnoses is peritoneal carcinomatosis. The imaging findings vary from multifocal discrete nodules to infiltrative masses. Infiltration of the small bowel mesentery may produce characteristic stellate pattern. Peritoneal lymphomatosis may mimic peritoneal carcinomatosis, but the presence of extensive adenopathy in lymph node chains typically involved with lymphoma, such as those in the retrocrural region and mesentery, may suggest lymphomatosis over carcinomatosis. [3, 4] Granulomatous peritonitis encompasses a wide range of unusual forms of peritoneal inflammation/infection that have overlapping imaging features. Crohn’s disease, sarcoidosis and Whipple disease have also been described as rare causes of granulomatous inflammation of the peritoneum. [3] Moreover, Whipple disease can lead to low-attenuation mesenteric lymphadenopathy, which may even have a fatty appearance due to infiltration of lipidladen macrophages. The CT combination of small bowel wall thickening and low-attenuation mesenteric adenopathy is most suggestive of either mycobacterial infection or Whipple disease; associated central nervous system or articular disease would favour the latter. [5]
Differential Diagnosis List
Lymph node and peritoneal tuberculosis
Peritoneal carcinomatosis
Peritoneal lymphomatosis
Sarcoidosis
Whipple disease
Final Diagnosis
Lymph node and peritoneal tuberculosis
Case information
URL: https://www.eurorad.org/case/10487
DOI: 10.1594/EURORAD/CASE.10487
ISSN: 1563-4086