Neuroendocrine Tumor of Tailgut Cyst with Unexpected Metastases.

Neuroendocrine tumors (NETs) originate from the neuroendocrine cells, which are found in various organs. NETs occur frequently in the gastrointestinal tract. NETs arising from tailgut cysts are uncommon. We herein report an interesting case of metastatic tailgut cyst NET, which was firstly diagnosed as plasmacytoma.

Interobserver and intraobserver agreement on prostate-specific membrane antigen PET/CT images according to the miTNM and PSMA-RADS criteria.

AIM: In this study, we aimed to measure interobserver and intraobserver agreement in Ga-68-prostate-specific membrane antigen (PSMA) PET/computed tomography (CT) image interpretation. In addition, the limitations of these criteria and levels of personal confidence reported by the readers when reporting the findings were determined. The effects of interpersonal differences on clinical decisions were also investigated. METHODS: PSMA PET images from 133 cases were reported independently by four different readers at different times according to the molecular imaging TNM (miTNM) and PSMA-reporting and data system (RADS) templates. RESULTS: There was substantial interobserver agreement for overall positivity, miT, miN and miM staging (Fleiss' κ = 0.65, 0.625, 0.731, and 0.779). Substantial agreement levels were observed in reporting of seminal vesicle invasion, the number of lymph node stations with metastasis, total number of intraprostatic areas containing tumors, and lymph node metastasis staging (Fleiss' κ = 0.622 and 0.779). The highest variation was seen in the reporting of intraprostatic distribution: In International Society of Urological Pathology (ISUP) grade group 1, moderate agreement was observed, and it was seen that the agreement level for the T staging increased with an increasing ISUP group in the staging group (Fleiss' κ = 0.531 vs. 0.655). There was near-perfect interobserver agreement in the reporting of five-point PSMA-RADS scoring [intraclass correlation coefficient (ICC) κ = 0.904; 95% CI, 0.865-0.934]. Disagreement according to miTNM staging had a major effect on clinical management in only 9% (n = 12) of the patients. CONCLUSION: PSMA PET has a lower interobserver variability and higher reproducibility than other imaging methods used for imaging of prostate cancer do, including CT, MRI, and bone scintigraphy. The miTNM template provides a reporting format that is highly reproducible and has a high level of agreement among readers, but the prostatic template needs development. In contrast, the PSMA-RADS system leads to slightly increased interobserver reporting differences and reduces personal confidence, but at the same time, it still exhibits almost-perfect agreement in terms of scoring.

The role of PSMA PET/CT imaging in restaging of prostate cancer patients with low prostate-specific antigen levels.

INTRODUCTION: Prostate-specific membrane antigen (PSMA) is increasingly being recognized as a novel target for the PET imaging of prostate cancer (PCa) and Ga-DKFZ-11 (Ga-PSMA) has been suggested as a novel tracer for detection of PCa relapses and metastases. The aim of this study was to evaluate the diagnostic value of PSMA PET/CT in the diagnosis of recurrent PCa with low prostate-specific antigen (PSA) levels. PATIENTS AND METHODS: We carried out a retrospective analysis of patients who underwent PSMA PET/CT from November 2013 to December 2014 in our department. Among these patients, 50 out of 178 who had increasing PSA levels (<5 ng/ml) and did not have known metastasis were included in this study. RESULTS: Patients had an average PSA of 1.41 ng/ml. A total of 29 patients (58%) showed at least one positive lesion. PET positivity rates of 31% (n=4), 54% (n=13), and 88% (n=14) were observed in patients with a PSA level of less than 0.2, 0.2-2, and 2-5 ng/ml, respectively. A positive correlation was observed between positivity rate and Gleason scores and blood PSA levels. Verification was performed in 46 patients, with biopsy (n=3) and follow-up, and conventional imaging studies at the time of the PET/CT or during follow-up with a mean period of 10.6±3.3 months and ranged from 3.8 to 16.4 months. According to patient-based analysis of 46 cases, 57% of patients had true positive, 24% of patients had true negative, 2% of patients had false positive, an 18% of patients had false-negative findings. A sensitivity of 76.47% (95% confidence interval: 58.83-89.25%) and a specificity of 91.67% (95% confidence interval: 61.52-99.79%) were found. CONCLUSION: PET/CT with Ga-PSMA is a valuable tool for assessing recurrence of PCa with a high sensitivity in patients who have PSA levels between 0.2 and 5 ng/ml. In addition, this study suggests that PSMA PET/CT can be used in patients with very low (<0.2 ng/ml) but increasing PSA levels, which, in many cases, may influence further clinical management.

The role of 68Ga-DOTA-TATE PET/CT scanning in the evaluation of patients with multiple myeloma: preliminary results.

OBJECTIVE: In this observational pilot study, we aimed to evaluate the role of gallium-68-labelled DOTA-TATE (Ga-TATE) PET/computed tomography (CT) scanning in patients with multiple myeloma (MM), considering previous promising results obtained from conventional somatostatin receptor scintigraphy with In pentetreotide. MATERIALS AND METHODS: Twenty-one patients with a diagnosis of MM were prospectively included in this study: eight patients were referred for initial staging and 13 patients for restaging purpose. Both fluorine-18 fluorodeoxyglucose (F-FDG) and TATE PET/CT scanning were performed in all patients. RESULTS: All patients had one or more PET-positive lesion on either F-FDG or TATE scans. Six patients had an additional diffusely increased bone marrow activity on F-FDG scans, five of whom also had a concordant bone marrow appearance on TATE scans. Each PET set (either F-FDG or TATE) was positive in 19 patients. There was a discordant result in four (19%) patients between F-FDG and TATE scans. F-FDG scans showed 112 lesions (86 TATE-positive; 26 TATE-negative) in 19 patients, whereas TATE scans showed 108 lesions (86 F-FDG-positive; 22 F-FDG-negative) in 19 patients. No significant difference was found between the two modalities in terms of lesion numbers detected (P=0.67). However, the presence of diffuse bone marrow uptake of TATE seems to be a predicting factor for the overall survival (P=0.033, hazard ratio: 15.2 and 95% confidence interval: 1.2-185.5). CONCLUSION: TATE PET/CT seems to be an alternative imaging modality and may play a complementary role in MM management, at least by providing a different pathobiological insight into the disease.

What is the role of florine-18 fluorodeoxyglucose/positron emission tomography/computed tomography imaging in well-differentiated thyroid cancers with negative iodine-131 scan high thyroglobulin and normal anti-thyroglobulin levels.

PURPOSE: This retrospective study aims to assess the cut-off value of thyroglobulin (Tg) levels in nux or metastatic well-differentiated thyroid cancers (DTCs) with normal anti-Tg levels using with fluorodeoxyglucose/positron emission tomography/computed tomography (FDG PET/CT). MATERIALS AND METHODS: We reviewed FDG PET/CT images of 104 patients with well DTC (28 men, 76 women) whose: Iodine-131 (131 I) whole-body scanning was negative but had elevated Tg with normal anti-Tg levels. RESULTS: The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of florine-18-FDG PET/CT findings were found to be 95.92%, 87.27%, 87.04%, 96.00%, and 91.35%, respectively. The best Tg cut-off value was found to be 10.4 ng/ml. In the Tg level <10.4 ng/ml group, the sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT were found to be 94.1%, 91.30%, 88.8%, 95.4%, and 92.5%, respectively. In the other group, which Tg level ≥10.4 ng/ml, sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT exams were found to be 96.8%, 84.3%, 86.1%, 96.4%, and 90.6%, respectively. CONCLUSION: FDG PET/CT imaging is a valuable imaging method in the evaluation of patients with elevated serum Tg levels and normal anti-Tg levels. Furthermore, it has potential utility in the dedifferentiation of active foci that are present, and in assessing optimal decision making during follow-up.

FDG PET/CT Imaging of an Isolated Recurrence in the Eyelid of a Patient With Follicular Lymphoma.

An 80-year-old woman had a history of follicular lymphoma diagnosed by biopsy of the inguinal lymph node 4 years prior. After systemic chemotherapy, she achieved complete remission. She presented with painless swelling on the left side of the eyelid. She also had suspicious lymph node enlargement in the cervical and axillary regions. FDG PET/CT showed an isolated FDG-avid lesion on the eyelid that was confirmed by biopsy to be compatible with lymphoma recurrence.

Evaluation of PSMA PET/CT imaging using a 68Ga-HBED-CC ligand in patients with prostate cancer and the value of early pelvic imaging.

PURPOSE: The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand (68)Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis. MATERIALS AND METHODS: The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients. RESULTS: Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n=25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV(max)) for primary tumour, lymph nodes and bone metastases was significantly higher in late images. CONCLUSION: PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions.

Regional ventilation/perfusion mismatch pattern in patient with Swyer James (MacLeod's) syndrome.

Swyer James (McLeod's) syndrome (SJMS) is an uncommon disease, which occurs as a result of childhood bronchiolitis obliterans. Patients may not be diagnosed until later in their life. A 46-year-old man underwent ventilation/perfusion scintigraphy for acute onset of dyspnea. The scan showed markedly diminished ventilation and perfusion unilaterally on the right middle and inferior lobes. However, mismatched ventilation-perfusion pattern was shown on the upper right lobe, which was consistent with pulmonary embolism. Unilaterally matched ventilation/perfusion defect can see in SJMS in lung scintigraphy; however, when pulmoner embolism may accompany, scintigraphy should be carefully examined.