Combined (18)F-FDG and (11)C-Methionine PET/CT scans in a case of metastatic hepatocellular carcinoma.

A 37-year-old male who underwent a central hepatectomy of the liver for hepatocellular carcinoma (HCC) was referred for an (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) study to rule out tumor recurrence or metastases. The scan showed a recurrent hepatic mass at the operative site, along with low-grade uptake in bilateral pulmonary metastases, mediastinal and hilar lymph nodes, and few skeletal sites. A non-FDG avid intracranial extradural mass was visualized in the right frontal lobe. The (11)C-methionine PET/CT scan performed subsequently revealed a larger area of involvement at the primary site, along with widespread metastases to the lungs, mediastinal, hilar, and abdominal lymph nodes, and multiple skeletal sites. Further, dural metastasis with high tracer uptake was noted in the frontal region. To the best of our knowledge, this is the first case documented in the literature, wherein (11)C-methionine PET/CT played a significant role in delineating the widespread dissemination, including the extremely rare dural involvement in a case of HCC. This report highlights the potential value of (11)C-methionine PET/CT in assessing the hepatic and extrahepatic tumor burden in cases of HCC, especially in clinically unexpected locations.

Cervical and uterine metastasis from carcinoma of breast diagnosed by PET/CT: an unusual presentation.

A 44-year-old apparently healthy woman presented with a 5-month history of intermittent vaginal bleeding. Clinical examination raised the suspicion of cervical neoplasia which was confirmed to be a metastatic adenocarcinoma on subsequent histopathological evaluation. An F-18 FDG PET/CT scan performed soon after revealed increased uptake in the cervix, extending upwards into the endometrial cavity. Additionally, small FDG avid spiculated soft tissue density masses were visualized in bilateral breast parenchyma, which proved to be lobular carcinoma on sonomammography followed by histopathology. Multiple lytic FDG avid skeletal metastases were also noted. Endometrial biopsy showed infiltrative malignant tumor with cytologic features similar to those observed in the breast biopsy specimen. The entire spectrum of findings pointed to a diagnosis of bilateral lobular carcinoma with uterine, cervical, and skeletal metastasis. Metastasis to the uterus and cervix from a breast primary is extremely rare. Most cases have been diagnosed in the follow-up of known cases of breast carcinoma. Our case is unique in that the patient, who had no prior history of breast carcinoma, was suspected to have a breast primary with cervical and uterine metastasis, based on the PET/CT findings.

The importance of 18F-FDG PET/CT, CT and X-rays in detecting primary stage III A lung cancer and the incidence of extra thoracic metastases.

Lung cancer (LC) has an unfavorable prognosis especially when the disease is extensive at presentation. Accurate staging is therefore needed for treatment planning of these patients. In the present study the role of positron emission tomography/computerized tomography (PET/CT) in the detection of extra thoracic metastases in LC is being evaluated. In all 52 of our patients with stage IIIA or lower of LC disease, a whole body (18)F-FDG PET/CT was performed. All patients were also subjected to general clinical evaluation, chest X-rays and chest contrast enhanced CT (CECT) and were confirmed by histopathology or magnetic resonance imaging or radiology. Incidental extra thoracic malignant lesions were found by (18)F-FDG PET/CT in 9 out of the 52 patients (17.3%). No false positive lesions were found. As for the primary LC diagnosed by fine needle aspiration cytology (FNAC): (18)F-FDG PET/CT diagnosed all 52 cases, CECT detected 46 cases and chest X-rays detected 28 cases. The diagnostic accuracy was 100%, 92% and 53.8% respectively. As for the 9 cases with extrathoracic metastases diagnosed by (18)F-FDG PET/CT they were confirmed: by biopsy 6, by MRI 2 and by X-rays with or without biopsy 2. In conclusion, (18)F-FDG PET/CT had better diagnostic accuracy in diagnosing LC stage IIIA or lower, than CECT or chest X-rays. Extrathoracic metastases were high: 9/52 as diagnosed by (18)F-FDG PET/CT and standardized up take value.

Prospective evaluation of CECT and 18F-FDG-PET/CT in detection of hepatic metastases.

OBJECTIVES: The purpose of this study was to evaluate the performance of F-fluorodeoxy-D-glucose (FDG)-PET/computed tomography (CT) and contrast-enhanced CT (CECT) in the detection and characterization of hepatic metastases. METHODS: Forty-five patients harboring an extrahepatic primary malignancy, with suspected hepatic metastases on clinical or ultrasonographic examination were enroled prospectively. Each patient underwent contrast-enhanced abdominal CT and F-FDG-PET/CT within 72 h of each other, reported by an experienced radiologist and nuclear medicine specialist, respectively in a blinded manner. CECT and PET-CT findings were compared and analyzed. Final diagnosis was based on histology and/or follow-up (ranging from 6 to 12 months). RESULTS: The sensitivity and specificity of CECT in the detection of hepatic metastases was 87.9 and 16.7%, respectively, whereas that of PET/CT was 97 and 75%, respectively. This study showed the superiority of PET/CT over CECT in the detection of hepatic metastases, irrespective of the primary site. This was especially owing to the latter's inability to reliably distinguish small (less than 15 mm) lesions as benign or malignant. CONCLUSION: Many studies have been conducted on the impact of FDG-PET/CT in the evaluation of hepatic metastases, especially from colorectal primary. Very few prospective studies, however, have been conducted on its role in evaluation of hepatic metastases from nongastrointestinal primaries. Despite its superior performance, it cannot replace CECT for this purpose, owing to the low but definite risk of false positivity based on PET-CT findings alone. Inclusion of CECT in PET/CT protocols may enable us to achieve a higher diagnostic accuracy. This suggests the need for a large prospective study with serial evaluations and pathological correlation.