Possibility of Differential Diagnosis of Small Polypoid Lesions in the Gallbladder Using FDG-PET

A Solitary Metastasis for a Malignant Schwannoma in the Gallbladder Detected by 18F-FDG PET/CT

A 63-year-old woman with a history of malignant schwannoma in the left shoulder (pT1aNxMx) was treated with surgical resection in 2012. During follow-up, patient developed a metastasis in the right lung treated by further surgical intervention. For a suspicion on persistent disease in the lung, patient was sent to FDG PET/CT examination, which showed a focal uptake in the gallbladder. The patient underwent cholecystectomy, and a solitary metastasis from schwannoma was diagnosed by pathology. This case highlights that, in patients with a malignant schwannoma, a careful differential diagnosis should be made in case of a significant FDG uptake in the gallbladder.

A literature review of radiological findings to guide the diagnosis of gallbladder adenomyomatosis

BACKGROUND

Gallbladder adenomyomatosis (GA) is a benign gallbladder entity discovered as an asymptomatic gallbladder mass. Since gallbladder cancer is in the differential diagnosis for gallbladder masses, the ability to differentiate benign disease avoids a more extensive oncologic resection. This study sought to review imaging modalities used to diagnose GA.

METHODS

PubMed and SciVerse Scopus were systematically searched using the terms: "gallbladder adenomyomatosis" and "gallbladder imaging" for articles published between January 2000 and January 2015.

RESULTS

A total of 14 articles were reviewed in this analysis. Contemporary series report the use of ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI) in GA imaging. Ultrasound detection of Rokitansky-Aschoff sinuses, visualized as small cystic spaces with associated "comet-tail" or "twinkling" artifact, is pathognomonic for GA. A "Pearl-Necklace" sign of small connected sinuses on MRI or "Rosary" sign on CT are additional characteristics that may assist in establishing a diagnosis.

CONCLUSION

Ultrasound is the most commonly used tool to investigate GA. If not diagnostic, CT or MRI are effective in attempting to differentiate a benign or malignant cholecystic mass. Characteristic signs should lead the surgeon to perform a laparoscopic cholecystectomy in symptomatic patients or manage non-operatively in asymptomatic patients.

Evidence based management of polyps of the gall bladder: A systematic review of the risk factors of malignancy

BACKGROUND

There are no evidence-based guidelines to dictate when Gallbladder Polyps (GBPs) of varying sizes should be resected.

AIM

To identify factors that accurately predict malignant disease in GBP; to provide an evidence-based algorithm for management.

METHODS

A systematic review following PRISMA guidelines was performed using terms "gallbladder polyps" AND "polypoid lesion of gallbladder", from January 1993 and September 2013. Inclusion criteria required histopathological report or follow-up of 2 years. RTI-IB tool was used for quality analysis. Correlation with GBP size and malignant potential was analysed using Euclidean distance; a logistics mixed effects model was used for assessing independent risk factors for malignancy.

RESULTS

Fifty-three articles were included in review. Data from 21 studies was pooled for analysis. Optimum size cut-off for resection of GBPs was 10 mm. Probability of malignancy is approximately zero at size <4.15 mm. Patient age >50 years, sessile and single polyps were independent risk factors for malignancy. For polyps sized 4 mm-10 mm, a risk assessment model was formulated.

CONCLUSIONS

This review and analysis has provided an evidence-based algorithm for the management of GBPs. Longitudinal studies are needed to better understand the behaviour of polyps <10 mm, that are not at a high risk of malignancy, but may change over time.

Stepwise approach and surgery for gallbladder adenomyomatosis: a mini-review

BACKGROUND

Gallbladder adenomyomatosis (GBA) is a hyperplastic disease affecting the wall of the gallbladder, with some typical features. It has historically been considered a benign condition, nevertheless recent reports highlighted a potential role of GBA in predisposing to malignancies of the gallbladder.

DATA SOURCES

We reviewed the literature concerning GBA from its identification until July 2012. Owing to the relative rarity of the disease, studies often are case reports or case series. Thus we herein report a summary of the key-points concerning diagnosis and treatment of GBA, easily applicable in everyday practice, rather than a systematic review. Also, results are integrated with our recent experience.

RESULTS

In our experience, we observed a trend toward an increase of GBA during the last years, probably due to enhanced ultrasonographic technical advancements and physician's expertise. GBA has distinctive imaging features. Several recent reports highlight the potential risk of cancer associated with GBA; however the disease is still classified as a benign condition. Although its correlation with malignancy has not been demonstrated, it is prudent to recommend cholecystectomy in some cases. However, in selected asymptomatic patients, a wait-and-see policy is a viable alternative. We propose an algorithm, based on GBA pathological pattern (diffuse, segmental, localized or fundal), suitable for decision-making.

CONCLUSIONS

In symptomatic patients and if the diagnosis is doubtful, cholecystectomy is mandatory. Postponing surgery is an option to be offered to asymptomatic patients with low-risk GBA pattern who adhere to scheduled follow-ups.

Role of 18F-FDG PET/CT in detecting recurrent gallbladder carcinoma

AIM

The present study was aimed to determine the efficacy of integrated FDG PET/CT in patients with gallbladder cancer (GBC) with suspicion of recurrent disease.

METHODS

A total of 49 patients (male: 15, female: 34; median age: 52.5 years) with GBC underwent FDG PET/CT for suspected recurrence. A total of 62 PET/CT scans were acquired. Criteria for detection by PET/CT were both a positive FDG uptake and the correct anatomic localization of the tumor. The PET/CT findings were grouped as locoregional disease and metastatic disease. Results of PET/CT were compared with clinical and radiologic follow-up and/or histopathology. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Results of PET/CT were also compared with conventional imaging (CI) whenever available.

RESULTS

Of 62 PET/CT, 43 (69.4%) were positive and 19 (30.6%) were negative for recurrence. Of 43 positive scans, 41 were true positive and 2 were false positive. Among 19 negative PET/CT scans, 18 were true negative and 1 was false negative. PET/CT showed a sensitivity of 97.6% and specificity of 90% in detecting tumor recurrence. The positive predictive value, negative predictive value, and accuracy were 95.3%, 94.7%, and 95.1%, respectively. Locoregional disease was seen in 16 (37.2%) PET/CT studies, distant metastases were seen in 13 (30.2%), and 14 (32.5%) studies showed both locoregional disease and metastasis. When comparable CI was available, PET/CT showed a better specificity than CI for detection of recurrence.

CONCLUSIONS

Integrated FDG PET/CT can detect recurrence in GBC with high sensitivity and specificity. Routine use of PET/CT in these patients will detect recurrence early and change the subsequent management.

Diagnosis and management of gallbladder polyps

Gallbladder polyps are frequently encountered on cross-sectional imaging, often in asymptomatic patients. Most are benign and of little clinical importance. However, some polyps do have a malignant potential. This article discusses the clinical presentation, diagnosis, and natural history of gallbladder polyps and risk factors for malignant polyps and indications for cholecystectomy.

Does PET-CT scan have a role prior to radical re-resection for incidental gallbladder cancer?

BACKGROUND

Radical re-resection is offered to patients with non-metastatic, invasive, incidental gallbladder cancer. Data evaluating (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) in patients with incidental gallbladder cancer is sparse.

AIM

To evaluate the efficacy of integrated (18)F-FDG PET-CT in determining occult metastatic or residual local-regional disease in patients with incidental gallbladder cancer.

METHODS

Patients referred with incidental gallbladder cancer for radical re-resection were evaluated using multidetector computed tomography (MDCT) and PET-CT. Based on preoperative imaging, 24 out of 92 patients were found suitable for surgery. The two imaging modalities were evaluated with respect to residual and resectable disease.

RESULTS

In determining residual disease, MDCT had a sensitivity and positive predictive value (PPV) of 42.8%, each, while PET-CT had a sensitivity and PPV of 28.5 and 20%, respectively. In determining resectability, MDCT had a sensitivity, PPV, and accuracy of 100, 87.5, and 87.5%, respectively, as compared to PET-CT (sensitivity=100%, PPV=91.3%, accuracy=91.6%).

CONCLUSIONS

From our study, it appears that in patients with incidental gall bladder cancer without metastatic disease, PET-CT and MDCT seem to have roles complementing each other. PET-CT was able to detect occult metastatic or residual local-regional disease in some of these patients, and seems to be useful in the preoperative diagnostic algorithm of patients whose MDCT is normal or indicates locally advanced disease.

Comparison of early and delayed FDG PET for evaluation of biliary stricture

OBJECTIVE

We assessed whether delayed FDG PET imaging is more useful for the evaluation of biliary stricture in differential diagnosis of malignancy from benign disease.

METHODS

Thirty-seven patients who underwent FDG PET for differential diagnosis of the disease causing biliary stricture were included. FDG PET imaging was performed at 70+/-12 min (early) post FDG injection and repeated 188+/-27 min (delayed) after injection only in the abdominal region. Image analysis was performed with visual interpretation and using a semi-quantitative method if lesion was visible on the PET image. The semi-quantitative analysis using the standardized uptake value (SUV) was determined for both early and delayed images (SUVearly and SUVdelayed, respectively). The tumour-to-normal liver (T/L) ratio was also calculated.

RESULTS

The final diagnosis was cholangiocarcinoma in 29 and benign disease in eight patients. In cases of cholangiocarcinoma, visual analysis of FDG PET using the delayed images, improve the diagnosis with one more patient correctly identified. For early and delayed FDG PET, sensitivities were 82.8% and 86.2%, respectively; specificities were 87.5% for both; and accuracies were 83.8% and 86.5%, respectively. Both SUV and T/L ratio derived from delayed images were significantly higher than those derived from early images for cholangiocarcinoma (P<0.0002 and P<0.0001, respectively).

CONCLUSION

FDG PET could be useful for differential diagnosis of malignancy from benign disease in patients with biliary stricture. Especially, the delayed targeted FDG PET imaging can be recommended in those patients when early imaging is negative or equivalent, because of increased lesion uptake and increased lesion to background contrast ratio.

Gallbladder metastasis from malignant melanoma: diagnosis with FDG PET/CT

Melanoma with metastasis to the gallbladder is sometimes seen on autopsy but is rarely seen in living patients, in part because it is often asymptomatic. A 67-year-old man with a history of malignant melanoma in situ underwent an F-18 FDG PET/CT scan, which showed a gallbladder focus (SUV 16.9). Four months later, on the repeat FDG PET/CT scan, a new lesion in the gallbladder was noted. Laparoscopic cholecystectomy was done and histopathologic findings were consistent with gallbladder metastasis of melanoma. PET/CT detects metastasis at unusual sites accurately and is helpful in correct staging and management of patients with melanoma.

Application of modern imaging methods in diagnosis of gallbladder cancer

The poor prognosis of gallbladder cancer (GBC) is related to its dissemination capacity and usually late diagnosis due to its non-specific clinical appearance. Recent improvements in hepatobiliary surgery have underlined the importance of an early specific diagnosis, which requires a multidisciplinary approach and, when possible, specialized equipment. The first step in an early diagnosis is to identify patients in the appropriate epidemiological setting (e.g., incidental finding, chronic cholecystitis) for the correct interpretation of test results. It is desirable to enhance the sensitivity of the initial ultrasound (US) examination by use of the appropriate technology in skilled specialist hands. When GBC is suggested by US findings, FDG-PET can be considered complementary to establish the benign/malignant nature of the lesion and to obtain a primary staging study. If GBC is confirmed, thin slice spiral CT can contribute valuable information on local spread. In this regard, recent hybrid PET-CT systems provide structural and functional information simultaneously and may offer early and accurate T, N, and M staging with an improved specificity.

Gallbladder Polyps

Most small gallbladder polyps are benign and do not change significantly over time. They are usually incidental findings on ultrasound. Therefore, these polyps should be checked periodically with routine percutaneous ultrasonography. In the asymptomatic patient, gallbladder polyps that are greater than 1 cm in diameter should be treated with cholecystectomy. The size of the polyp and the patient greater than 50 years are important risk factors for malignant potential. Patients who have biliary pain and small gallbladder polyps without gallstones present a difficult management decision for the clinician. If the physician is confident that the polyps are the source of the pain, patients should be referred for cholecystectomy. Endoscopic ultrasound and positron emission tomography may prove to be useful in assessing the malignant potential of large gallbladder polyps. Laparoscopic cholecystectomy is the treatment of choice for most gallbladder polyps. If a malignant polyp is suspected, patients should undergo an open cholecystectomy.

Ultrasonography in the diagnosis of true gallbladder polyps: the contradiction in the literature

Polypoid lesions of the gallbladder (PLGs) are often incidentally identified during ultrasonographic examination of abdominal pain. The present study was designed to determine the reliability of ultrasonography (US) in the diagnosis of PLGs. The records of 853 patients who underwent laparoscopic cholecystectomy (LC) for PLGs in Gazi Medical School from January 2000 to January 2004 were reviewed. Data were collected regarding the patients' gender, age, symptoms, serum lipid levels, the size and the number of polyps on US, surgical indications for PLGs and histopathological diagnosis. In all, 56 of 853 patients had PLGs and underwent LC. Right upper quadrant pain (59%) was the most common presenting symptom that led to gallbladder US. Nearly 75% of the lesions were smaller than 10 mm. At histopathologic examination cholesterolosis was found in 17 of 56 (30%) patients, and 12 of 56 (21%) demonstrated only cholelithiasis; 17 (30%) patients had both cholesterolosis and stones. Only 10 (18%) patients had adenomatous polyp and 8 of these polyps were larger than 1 cm. Overall US-based diagnosis of gallbladder polyp was inaccurate in 82%. The sensitivity and specificity of US for polyps <1 cm was 20% and 95.1%, respectively, whereas the sensitivity and specificity of US for polyps >1 cm was 80% and 99.3%, respectively. The accuracy of US in diagnosing PLGs was poor, especially in polyps <1 cm.

Polypoid lesions of the gallbladder

BACKGROUND

Polypoid lesions of the gallbladder encompass a wide variety of pathology. Although most of these lesions are benign, some early carcinomas of the gallbladder do present as polypoid lesions. Problems remain in selecting patients with polypoid lesions of the gallbladder for surgery, the operative approach, and the method of follow-up of those deemed not needing surgery.

DATA SOURCES

This review was done by Medline search of the English literature by the keywords "polypoid lesions of gallbladder," "gallbladder polyps," "carcinoma of gallbladder," and "benign tumors of gallbladder."

CONCLUSIONS

Most small polypoid lesions of the gallbladder are benign and remain static for years. Three- to six-monthly ultrasonography examination is warranted in the initial follow-up period but it is probably unnecessary after 1 or 2 years. Age more than 50 years and size of polyp more than 1 cm are the two most important factors predicting malignancy in polypoid lesions of the gallbladder. Other risk factors include concurrent gallstones, solitary polyp, and symptomatic polyp. Laparoscopic cholecystectomy is the treatment of choice unless the suspicion of malignancy is high, in which case it is advisable to have open exploration, intraoperative frozen section, and preparation for extended resection.

Positron-emission tomography with fluorine-18-fluoro-2-deoxy-D-glucose for gallbladder cancer diagnosis

BACKGROUND

Recent advances in hepatobiliary surgery have underscored the need for presurgical diagnosis of gallbladder cancer. Frequently, clinical presentation, biochemical analysis, and structural ultrasound or computed axial tomography images do not enable definitive differentiation of cholecystitis or cholethiasis from gallbladder cancer. The aim of this study was to evaluate the role of fludeoxy glucose-positron-emission tomography (FDG-PET) in establishing the benign or malignant nature of gallbladder lesions.

METHODS

A case series of 16 patients with clinical symptoms suggestive of biliary colic or chronic cholecystitis and with inconclusive ultrasound and/or computed axial tomography findings for presence of gallbladder cancer were studied by FDG-PET.

RESULTS

FDG-PET showed a sensitivity of 0.80, a specificity of 0.82, and positive and negative predictive values of 0.67 and 0.90, respectively. There was 1 false- negative result in 1 patient with mucinous adenocarcinoma and 2 false-positive results in 1 patient with tuberculoid granulomatous reaction and 1 patient with polypoid lesion with adenomyomatosis.

CONCLUSIONS

FDG-PET may be of utility to establish the diagnosis of gallbladder cancer in patients with nonspecific clinical and imaging findings.

Fluorodeoxyglucose PET imaging in the evaluation of gallbladder carcinoma and cholangiocarcinoma

Our goal was to evaluate fluorodeoxyglucose (FDG) positron emission tomography (PET) in staging patients with biliary tract cancers. Fifty consecutive patients who underwent FDG-PET for suspected cholangiocarcinoma (n=36) or gallbladder carcinoma (n=14) were reviewed. Patients with cholangiocarcinoma were divided into two groups: group 1 had nodular type (mass=1 cm) (n=22) and group 2 had infiltrating type (n=14) cholangiocarcinoma. Thirty-one of 36 patients evaluated for cholangiocarcinoma had cholangiocarcinoma and five did not. Sensitivity was 85% for nodular morphology but only 18% for infiltrating morphology. Sensitivity for metastases was 65% but false negative for carcinomatosis in three of three patients. One false positive result occurred in a patient with primary sclerosing cholangitis who had acute cholangitis. Seven (58%) of 12 patients had FDG uptake along the tract of a biliary stent. FDG-PET led to a change in surgical management in 30% (11 of 36) of patients evaluated for cholangiocarcinoma because of detection of unsuspected metastases. Eleven of 14 patients with gallbladder carcinoma were newly diagnosed by cholecystectomy or another type of exploratory procedure, whereas three patients were undergoing follow-up. Nine had residual gallbladder carcinoma at the time of PET. Sensitivity for gallbladder carcinoma was 78%. Sensitivity for extrahepatic metastases was 50% in eight patients; six of them had carcinomatosis. These data suggest that PET is accurate in predicting the presence of nodular cholangiocarcinoma (mass>1cm) but was not helpful for the infiltrating type. PET was also helpful for detecting residual gallbladder carcinoma following cholecystectomy, but was not helpful in patients with carcinomatosis. Although FDG-PET led to a change in management in 30% of patients with cholangiocarcinoma, it must be interpreted with caution in patients with primary sclerosing cholangitis and with stents in place, as well as in those with known granulomatous disease.