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Abdomen » Peritoneal Cavity
Abdominal Tuberculosis With Tuberculous Lymphadenitis and Psoas Abscess
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Presentation 21-year-old female presents to the ED complaining of left-sided flank pain since approximately 9 p.m. the previous night. She has nausea and vomiting, and complains of light-headedness when standing upright. The patient also describes bilateral pelvic cramping, which the patient associates with her menses. No dysuria. Previous medical history is unremarkable.
 
 
 
Caption: CT Abdomen
Description: CT of the Abdomen and Pelvis Without and With IV Contrast and No Oral Contrast. Probable cavernous hemangioma in the posteromedial spleen measures 9 mm in diameter and shows nodular peripheral enhancement.
 
 
 
Caption: CT Abdomen
Description: 
 
 
 
Caption: CT Abdomen
Description: 
 
 
 
Caption: CT Abdomen
Description: Multiple peripherally enhancing low-attenuation masses within the body and tail of the pancreas and the mesenteric root anterior to the pancreas. Splenic vein thrombosis with isolated gastric varices from the spleen to the portal vein. The superior mesenteric vein and portal vein are patent.
 
 
 
Caption: Ct Pelvis
Description: Low-density enhancing mass or fluid collection within the right posterior psoas muscle measures 4.5 cm in diameter and 6.3 cm in length along the psoas. Anterior and medial to the psoas are multiple enhancing low-density masses along the right external iliac lymph node chain.
 
 
 
Caption: CT Pelvis
Description: Findings consistent with metastatic mucinous adenocarcinoma from an unknown primary, most likely from a mucinous cystadenocarcinoma of the pancreas.
 
 
 
Caption: Transverse through head of pancreas
Description: Ultrasound of the abdomen demonstrated normal-appearing liver, bile duct caliber, and gallbladder. Several irregular, partially cystic lesions are demonstrated around the pancreas. These should correspond to intra-abdominal abscesses seen on the prior CT scans.
 
 
 
Caption:  Color Doppler of peripancreatic masses
Description: No vascularization is seen within the mass.
 
Differential Diagnosis •    Cystic pancreatic neoplasm with metastatic lymphadenopathy.
•    Intraabdominal abscesses with necrotic lymphadenopathy.
•    Metastases from other mucinous tumors (ovary, appendix).

A second pertinent differential for this case is that of low-density abdominal lymphadenopathy, which includes granulomatous infections (such as TB, MAI, and fungal), metastasis (e.g., melanoma, squamous cell carcinoma, and testicular tumors in a male patient), atypical lymphoma (usually bulky or treated), Whipple's disease, celiac sprue, Castleman’s disease, and Crohn’s disease.

 
Final Diagnosis ABDOMINAL TUBERCULOSIS WITH TUBERCULOUS LYMPHADENITIS AND PSOAS ABSCESS.

(Tuberculous involvement was proven by DNA probe of the psoas abscess aspiration 9/30/04 and eventually confirmed by culture from the endoscopic aspiration of necrotic peripancreatic lymph nodes, 9/16/04.  The biopsy of the peripancreatic lesions also showed reactive lymphoid hyperplasia with abundant proteinaceous debris and histiocytes, as well as fragments of acutely inflamed pancreatic parenchyma.)

 
Discussion Tuberculosis (TB) is caused by the pathogen Mycobacterium tuberculosis and causes approximately 3 million deaths per year worldwide.  The incidence of TB is increasing in both the developed and the developing world.  The increasing incidence of TB has been associated with increasing numbers of immunocompromised patients, largely related to the global AIDS pandemic [1].

While the majority of TB cases involve the pulmonary system, extrapulmonary forms of TB also exist.  Extrapulmonary tuberculosis is known to be a very challenging diagnosis to make.  While chest radiograph findings and a positive tuberculin skin test can support the diagnosis, negative results do not exclude extrapulmonary TB.  Frequent sites of extrapulmonary TB include genitourinary (most common), bones (most frequently the spine), joints (typically monoarticular in the knee or hip), and CNS [2].  Extrapulmonary involvement of TB is more common in patients with HIV than in non-HIV patients; it is estimated to occur in 10-15% of patients not infected with HIV, while 50-70% of patients with HIV have extrapulmonary manifestations [3].

Abdominal TB constitutes up to 12% of all cases of extrapulmonary TB.  Abdominal involvement may occur in the gastrointestinal tract, peritoneum, lymph nodes, or solid viscera [4].  Abdominal TB does not usually co-exist with active pulmonary TB in the same patient; the percent of cases in which abdominal TB is found in conjunction with active pulmonary TB is only 6-38%.  The manifestations of abdominal TB are nonspecific, and the condition has been well-recognized as a great mimicker of other abdominal pathology, both clinically as well as on imaging studies.  In particular, there are many case reports in the literature describing incidences where abdominal TB has been mistaken for neoplasm, as in the case presented here [1].

The pathogenesis of abdominal TB is most likely related to ingestion rather than inhalation of the organism.  Once the organism is ingested, necrotic granulomas form in the intestine, and the organism in turn spreads to the lymphatics in a miliary pattern.  From there, the infection can then go on to affect practically any organ in the gastrointestinal system [5].

Given this lymphatic spread of TB in the abdomen, it is not surprising that the most common form of abdominal TB is tuberculous lymphadenitis.  The nodes are usually large and multiple, measuring 2-3 cm on average.  The mesenteric, periportal, and peripancreatic lymph node groups are most commonly affected [6].  TB can also infrequently involve the pancreas itself.  Peripancreatic lymph node involvement and pancreatic disease are often difficult or impossible to distinguish, clinically as well as on diagnostic imaging, since no capsule exists in the pancreas.  In cases with low density lesions in the peripancreatic region, a broad differential diagnosis of cystic pancreatic masses must be considered, which can include serous cystadenoma, mucinous cystic neoplasms, IPMN, and pancreatic pseudocysts [8].  A psoas abscess in a patient with TB can be associated with TB of the spine (Pott’s disease).

Clinically, the symptoms of abdominal TB lymphadenitis are varied and nonspecific, and include abdominal pain, fever, weight loss, abdominal mass, jaundice, nausea, vomiting, and diarrhea.  Tuberculous lymph node involvement typically appears on CT as a nonspecific hypodense mass or masses with peripheral enhancement, often with irregular borders and a multilocular appearance [7].  The ultrasound appearance of TB lymphadenitis is likewise nonspecific, demonstrating hypoechoic, cystic or partially cystic lesions.  

Positive culture, DNA probe, or histologic analysis of a biopsy specimen is often required for a definitive diagnosis.  Methods of biopsy include CT or US guided percutaneous biopsy, endoscopic ultrasound guided biopsy, and surgical (open or laparoscopic) biopsy.  In most cases in the literature, a diagnosis was made only after exploratory laparotomy.  Once a diagnosis is made, both medical management for the infected individual and prevention of infectious spread to uninfected individuals must be initiated [8].  Abdominal TB is generally responsive to medical treatment alone, so early diagnosis can prevent unnecessary surgical intervention [1].

This patient described in this case was originally from Somalia, and denied any history of TB or known TB exposure.  A TB skin test was eventually obtained, which was positive.  TB cultures from endoscopic aspiration of perigastric lymph nodes took almost 2 months to return positive results; however, a DNA probe performed on the fluid aspirated on 9/30/04 from the psoas abscess came back positive within 3 days.  A drain was placed into the psoas abscess under CT guidance at the time of the CT guided aspiration, and this abscess subsequently resolved.  The other low density lesions in the retroperitoneum and along the iliac chains resolved with medical therapy.  The organism in this case was eventually shown to be multidrug resistant, and at last follow-up the patient was following a five drug regimen of anti-TB drugs, and improvement was noted both clinically and on follow-up CT scans.

 
Case References 1.    Uzunkoy A, Harma M, Harma M.  Diagnosis of abdominal tuberculosis: Experience from 11 cases and review of the literature.  World Journal of Gastroenterology 2004; 10(24):3647-3549.
2.    Engin G, Acunas B, Acunas G, et al.  Imaging of extrapulmonary tuberculosis.  Radiographics 2000; 20:471-488.
3.    Runyon BA.  Textbook of Gastroenterology 2nd ed.  Philadelphia: Lippincott 1995: 928.  
4.    Sheer TA, Coyle WJ.  Gastrointestinal tuberculosis.  Curr Gastroenterol Rep 2003; 5: 273-278.
5.    Sinan T, Sheikh M, Ramadan S, et al.  CT features in abdominal tuberculosis: 20 years experience.  BMC Medical Imaging 2002;2:3-10.
6.    Hulnick DH, Megibow AJ, Naidich DP, et al.  Abdominal tuberculosis: CT evaluation.  Radiology 1985; 157:199-204.
7.    Yang, ZG, Min, PQ, Sone, S, et al. Tuberculosis versus lymphomas in the abdominal lymph nodes: evaluation with contrast-enhanced CT. AJR Am J Roentgenol 1999; 172:619.
8.    Weiss ES, Klein WM, Yeo CJ.  Peripancreatic TB mimicking pancreatic neoplasia.  J Gastroint Surg 2005; 9(2):244-262.

 
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