A 47-year-old man was referred to our hospital with a 3-month history of abdominal distension, intermittent abdominal pain and nausea. Despite weight loss of 4 kg, the patient had no symptom of fever, chronic cough or night sweats. He had no history of abdominal surgery, liver cirrhosis or chronic hepatitis virus infection, but suffered from tuberculous pleurisy about 20 years ago. Physical examination revealed gross abdominal distension without tender and ascites of unknown aetiology. Laboratory blood analyses including serum tumor markers, erythrocyte sedimentationrate (ESR), adenosine deaminase activity (ADA) and anti-tuberculosis antibody (TB-Ab) were all within normal limits, and tuberculin skin test was negative. The results of antibody testing for HIV were negative. Chest radiograph did not demonstrate features suggestive of pulmonary tuberculosis. Plain upright abdominal X-ray showed some air in the colon without presence of air fluid levels in the loops or free gas under the diaphragm (Fig. 1a). Contrast-enhanced computed tomogram (CT) of the abdomen (Fig. 1b, c) revealed dilatation of the duodenum loops (*) and congregated small gut loops (black arrowhead) trapped in the massive ascites surrounded by a membrane (white arrowhead). Gastroscopy revealed no signs of malignancy. A peritoneal tap was performed twice and yielded blood stained ascitic fluid but no malignant cells or acid-fast bacilli. The ascities was exudates in nature and ascities ADA was within normal ranges. The patient refused laparoscopy examination and was discharged without a definitive diagnosis and further treatment.
Two months later, the patient was presented to our hospital again with persistent symptoms. Despite abdominal distension, nausea and vomiting, he also complained of increasing fatigue, emaciation, and 10-kg weight loss for the recent two months. Laboratory blood analyses revealed that serum ADA was 21 U/L (normal range 4-18 U/L), ESR was 28 mm/h (normal range 0-15 mm/h), but TB-Ab was negative. Ascitic fluid obtained by paracentesis was still negative for bacteria, acid-fast bacilli and malignant cells, but ascities ADA was significantly elevated (41 U/L). Serum CA-125 was also significantly elevated (97.39 U/ml, normal range < 35 U/L). In addition, despite the presence of well-encapsulated fluid collection and central accumulation of the small intestine (Fig. 2a), CT scan also revealed smudged appearance of the greater omentum (Fig. 2b,*), as well as multiple small nodules and sheetlike lesions on the parietal peritoneum (Fig. 2. s, arrowhead), which the radiologists considered to be peritoneal carcinomatosis (PC). Mesenteric lymphadenopathy was not observed on CT scan. The presumptive diagnosis was PC or tuberculous peritonitis in our patient, however, other differential diagnosis, such as peritoneal mesothelioma, could not be completely ruled out.
Diagnostic laparoscopy was performed in our patient, and the entire small bowel was found to be encapsulated in a dense, white, fibrous, cocoon-like membrane filled with a large amount of brownish ascites (Fig. 2d). Multitudinous miliary nodules or tubercles were seen on the parietal peritoneum and greater omentum. Biopsy of the nodules and plaques revealed caseous granulomatous inflammation and the specimen were stained positive for acid-fast bacilli. Histopathology of the cocoon wall revealed fibrocollagenic tissue with granulomatous inflammation, and culture of the biopsied specimen grew Mycobacterium tuberculosis 3 weeks later. A diagnosis of tuberculous abdominal cocoon was made. Complete excision of the thick membrane and lysis of adhesions were tried but failed due to the extreme difficulty in separating the fibrotic tissue from the abdominal wall and small bowel. Since there were no perforated, ischemic or dilated bowel loops, the operation was completed after obtaining samples for diagnostic biopsy.
After operation, the patient had recurrent episodes of partial bowel obstruction that was resolved with conservative management. The patient was given rifampicin, isoniazid, ethambutol, and pyrazinamide for 2 months, followed by rifampicin and isoniazid for 4 months. By the end of the 2 month of anti-tuberculous therapy, serum ADA, ESR and CA 125 levels have returned to normal. Though a repeat CT scan of the abdomen and pelvis continued to show the small bowel wall thickening and membrane covering the small bowels (Fig. 3a, arrowhead), and gastrografin meal follow through study revealed adherent small bowel loops with delayed transit time (Fig. 3b), however, the ascites has greatly diminished and the patient was functioning normally. No further surgical intervention was planned for him, and he was followed up symptom-free for 6 years.