DIAGNOSTIC DILEMMA

Aimee K. Zaas, MD, Section Editor

Unusual Enhancing FociAbhishek Agarwal, MD,a Meghana Bansal, MD,a Rebecca E. Martin, MDb

aDepartment of Internal Medicine, bDivision of Infectious Diseases, University of Arkansas for Medical Sciences, Little Rock.

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PRESENTATIONPressure to treat can discourage physicians from carryingout the careful investigations needed for correct diagnosis.Here, we describe a case in which the correct diagnosis tookseveral years, and became apparent only after a review ofpatient records revealed a decade-old surgical history oflaparoscopic cholecystectomy performed for acute calcu-lous cholecystitis.

The patient, a hypertensive 78-year-old man, presentedwith fevers and increased abdominal pain 4 weeks afterbeginning chemotherapy for the presumed recurrence of agastrointestinal stromal tumor. Three years previous to thispresentation, he had undergone endoscopy during an eval-uation for melena; the procedure had revealed a 1-cm sub-mucosal abdominal mass that was identified by pathologicanalysis as a low-grade gastrointestinal stromal tumor. Thetumor had been removed by a partial gastrectomy withoutany further imaging studies, and because it was small andlow-grade, with non-malignant surgical margins, no chemo-therapy had been prescribed. The management plan hadbeen to follow the patient by periodic abdominal imagingwith computed tomography (CT).

The first follow-up CT, recorded 3 months after thegastrectomy, had revealed a soft-tissue density with some“enhancing foci” inferolateral to the right lobe of the liverand a right pleural effusion (Figure 1). These findings wereconsidered unusual for a recurrence of a gastrointestinalstromal tumor, which tends to recur locally. The pleuralfluid was exudative and contained 1600 white bloodcells/�L (21% neutrophils, 46% lymphocytes, and 23%macrophages), but cultures and cytology studies were neg-ative for infection and malignancy. A tuberculin skin testwas negative. A workup for malignancy, including upper

Funding: None.Conflict of Interest: None.Authorship: All authors had access to the data and were involved in

the conception and drafting of this article.Requests for reprints should be addressed to Abhishek Agarwal, MD,

Division of General Internal Medicine, Department of Medicine, Univer-sity of Arkansas for Medical Sciences, Slot 641, 4301 W. Markham Street,Little Rock, AR 72205.

pE-mail address: aagarwal@uams.edu

0002-9343/$ -see front matter © 2012 Elsevier Inc. All rights reserved.doi:10.1016/j.amjmed.2011.07.013

and lower gastrointestinal endoscopies, a bone scan, andserum analysis for tumor markers, was negative. Over thecourse of the next 3 years, follow-up CT scans had shownslow enlargement of the mass.

Four weeks prior to the current visit, the patient hadpresented with subjective fevers, anorexia, and right upper-quadrant abdominal pain of 3 months duration, as well as agradual weight loss of 40 pounds over the preceding 2 years.He had no chest pain, cough, melena, hematochezia, orchange in bowel habits. He used chewing tobacco and hadfamily history (brother) of lung cancer. An abdominal CTscan during that visit had shown a further increase in thesize of the mass. A positron emission tomography (PET)scan showed increased glucose uptake in the mass infero-lateral to the right lobe of the liver, as well as in theascending colon, bilateral hilar lymph nodes, and anteriorabdominal wall, consistent with peritoneal metastases (Fig-ure 2). Fine-needle aspiration cytology of the mass hadshown only non-specific inflammatory cells, but the nightsweats, anorexia, weight loss, and slow tumor enlargementseemed to suggest a recurrence of the gastrointestinal stro-mal tumor, and imatinib chemotherapy had been initiated.

ASSESSMENTOn examination, the patient was febrile at 38.3°C. He had alarge (10-cm) palpable mass over the right anterior chestand abdominal wall and decreased air entry over the rightlower-lung field, prompting hospital admission. Pertinentlaboratory results were as follows: hemoglobin, 12 mg/dL;white blood cell count, 13,000/�L (82% neutrophils, 14%ymphocytes); serum bilirubin, 1.1 mg/dL; aspartate amino-ransferase, 32 IU/L; and alkaline phosphatase, 170 IU/L.he CT scan showed marked enlargement of the mass with

nvasion of the anterolateral chest and abdominal wall (Fig-res 3 and 4). An attempt at fine-needle aspiration returnedross pus. Cytology on the fluid was negative, but culturesrew Klebsiella pneumoniae.

An examination of patient’s records from his cholecys-ectomy performed 10 years previously revealed that theallbladder had ruptured during surgery, spilling bile and

igment stones into the abdominal cavity, and that the

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32 The American Journal of Medicine, Vol 125, No 1, January 2012

gallbladder specimen had grown K. pneumonia. His mostrecent treating physicians had been unaware of this surgicalcomplication. A review of the CT scans in light of the newinformation suggested that the “enhancing foci” within themass might be gallstones (arrows in Figures 1 and 3).

DIAGNOSISThe mass that had been followed as a suspect tumor for 3years was diagnosed as an intra-abdominal bacterial abscessresulting from gallstone spillage during the patient’s lapa-roscopic cholecystectomy 10 years ago. Laparoscopic cho-

Figure 1 CT image showing a mass with 2 gallstones (ar-row) inferolateral to the liver.

Figure 2 PET-CT images showing glucose uptake in the liver,

nodes.

lecystectomy is associated with a fairly high rate of gall-bladder perforation (5-40%), but the incidence of resultantcomplications is low (0.08-0.3%), and most patients remainasymptomatic.1,2 The length of time between gallstone spill-ge and the reported complications ranges widely, from aew days to as long as 20 years.3 Because the symptoms areonspecific, mimicking several more common pathologies,he correct diagnosis is often delayed considerably.

Abscesses, the most frequent complication of spilledallstones, are often confused for a malignancy. They occurredominantly in the liver or hepatic area4 but also can

occur at more distant sites, such as the abdomen and retro-

lateral to the liver, in the ascending colon, and in the hilar lymph

Figure 3 CT image showing enlargement of the abscess withan embedded gallstone (arrow).

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33Agarwal et al Abscess from Spilled Gallstones

peritoneum.5 Cultures from these abscesses usually growbacteria typically associated with acute cholecystitis, suchas E. coli, Klebsiella, or Enterococcus species.2 Other re-ported complications include non-healing fistulas and sinusformation,6 intestinal obstruction,7 appendicitis,8 incarcer-ated hernias,9 obstructive cholangitis,10 thoracic abscesses,nd empyema.11 Pelvic migration of the stones can cause aranulomatous peritonitis mimicking endometriosis12 and

sometimes resulting in dyspareunia and tenesmus. In onereported case, the spilled gallstones had been seeded withStaphylococcus aureus from a septic knee, resulting in re-current episodes of staphylococcal bacteremia until thestones were identified and removed.13

Most pigment stones harbor bacterial microcolonies thatproduce stone-promoting �-glucuronidase, slime, and phos-pholipase.14 In our patient, the pigmented stones and bilethat spilled into the peritoneum during surgery were in-fected with K. pneumonia. The weakening of the host im-munity by chemotherapy allowed the bacteria to multiply inan aggressive fashion, leading to a marked enlargement ofthe abscess and the eventual diagnosis.

CT, magnetic resonance, and ultrasound imaging canplay important roles in the radiologic diagnosis of theseabscesses. In particular, CT scans can reveal calcificationsconsistent with gallstones and can provide guidance in per-cutaneous drainage. However, the stones can be missed onimaging studies, as occurred for several years in this case.

MANAGEMENTSpilled gallstones behave as a foreign body, and a failure toidentify and remove them can lead to multiple surgeries thatfail to resolve patient symptoms.3 If the stones are notretrieved for reason of high surgical risk or patient prefer-ence, prolonged antibiotic treatment may be needed. Our

Figure 4 CT image showing invasion of the right chest andabdominal wall.

patient refused surgery to retrieve the stones. The abscess

was drained percutaneously, and the patient was treated forseveral months with ciprofloxacin (for the Klebsiella) andmetronidazole (for possible concomitant infection with an-aerobes). He gained weight, the fevers resolved, and theabscess shrank significantly.

Even though imatinib is associated with low toxicity, itsempiric use for treatment of a presumed gastrointestinaltumor is not the usual practice. A better approach would beto pursue open biopsy for mass lesions that remain suspi-cious for malignancy despite negative cytology. In our pa-tient, imaging studies performed prior to the gastrectomycould have revealed the enhancing foci and prevented thesubsequent misdiagnosis of a tumor recurrence. Radiolo-gists and other physicians should be alert to the possibilityof spilled gallstones in patients with a history of laparo-scopic cholecystectomy, and a meticulous surgical historyand access to operative reports are helpful in the diagnosis.

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