Comparison between total thyroidectomy and hemithyroidectomy in TIR3B thyroid nodules management.

PURPOSE: Thyroid nodules classified as TIR3B according to SIAPEC 2014 are considered a clinical challenge due to the risk to be malignant. This retrospective study aimed to compare the performances of total thyroidectomy (TT) and hemithyroidectomy (HT) in the surgical management of a consecutive cohort of patients affected by TIR3B thyroid nodule in terms of side effects and the rate of malignancy detected. METHODS: From 2011 to 2019, 136 (111 women, 25 men; average age of 53.5 years) patients having a thyroid nodule with a cytological diagnosis of TIR3B who underwent TT or HT were retrospectively included. RESULTS: Out of 136 patients, 106 (78%) received TT, while the remaining 30 (22%) HT. The final diagnosis was malignant in 65 patients (48%), with follicular variant of papillary carcinoma as the most frequent. The diagnosis of malignancy was significantly more common in the TT group with 56 patients (53%) compared to the HT group with 9 cases (30%) (p = 0.001). Patients who underwent TT were significantly older, had larger nodules and the time between diagnosis and surgery was significantly longer compared to HT (p = 0.001; p0.003; p = 0.002). No main post-surgical complications were registered, except for one case of transient hypocalcemia in a patient who underwent TT. CONCLUSIONS: Our data showed a malignancy rate of TIR3B lesions higher than expected (48%). Both TT and HT seem to be effective approaches for the treatment of TIR3B nodules with a very low rate of post-surgical comorbidities. In the choice of surgical approach, it is crucial to consider the presence of risk factors (clinical and ultrasound characteristics), nodule size, patients' opinion, and surgeon's skills and experience.

[18F]FDG PET/CT and CA-125 in the evaluation of ovarian cancer relapse or persistence: is there any correlation?

BACKGROUND: Ovarian cancer relapse can be diagnosed by serum tumor markers measurements and 18F-fluorodoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) findings. The aim of our study was to analyze the potential relationship between cancer antigen 125 (CA-125) and PET/CT results in patients affected by ovarian cancer. MATERIAL AND METHODS: Ninety-two [18F]FDG PET/CT scans in sixty-one patients with diagnosis of ovarian cancer were analyzed and compared to CA-125 values. PET/CT results were compared to other imaging modalities, histology or follow-up data in order to define its diagnostic accuracy. PET/CT studies were analyzed qualitatively and semiquantitatively by measuring the maximum and mean standardized uptake value body weight max (SUVbw max, SUVbw mean), maximum SUV lean body mass (SUVlbm), maximum SUV body surface area (SUVbsa), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of hypermetabolic lesions. All measurements were compared with CA-125 values. RESULTS: Twenty PET/CT studies were true negative, sixty-three true positive, five false positive and four false negative with sensitivity of 94%, specificity of 80%, negative predictive value of 83%, positive predictive value of 93% and accuracy of 90%. CA-125 levels were significantly correlated with PET/CT results and all PET/CT semiquantitative parameters. CA-125 cutoff values of 17 UI/mL is the best compromise between sensitivity and specificity in discriminating between positive and negative PET/CT result. CONCLUSIONS: [18F]FDG PET/CT has good accuracy in evaluating patients with relapse or persistance of ovarian cancer. CA-125 levels were significantly correlated with metabolic PET/CT parameters.

18F-FDG PET/CT Demonstrating Crossed Cerebellar Diaschisis Due to Germ Cell Tumor of the Basal Ganglia: A Case Report.

ABSTRACT: Germ cell tumors of the basal ganglia are rare neoplasms that usually present with hemiparesis or other neurological symptoms. MR and PET/CT with different tracers have demonstrated their usefulness for the correct assessment of disease. Crossed cerebellar diaschisis refers to a depression in metabolism of a cerebellar hemisphere as a result of contralateral supratentorial lesions. We present a case in which MR and PET/CT were crucial for the assessment of left basal ganglia germ cell tumors with the presence of crossed cerebellar diaschisis.

Correlation between brain glucose metabolism (18F-FDG) and cerebral blood flow with amyloid tracers (18F-Florbetapir) in clinical routine: Preliminary evidences.

OBJECTIVE: This study compared the performance of 18F-Florbetapir PET/CT early acquisitions to 18F-FDG PET/CT. METHODS: We included 12 patients who underwent 18F-FDG PET/CT and a dual-time 18F-Florbetapir PET/CT (1-6 min early-scan and 50 min late-scan). PET/CT were analyzed visually by three nuclear medicine physicians with different experience using a four-point scale (0 = no reduction, 1 = slight, 2 = moderate, 3 = severe reduction) for 18F-Florbetapir early-phase and 18F-FDG images in 10 cortical regions (bilateral frontal, temporal, parietal, occipital, posterior cingulate/precuneus), and 18F-Florbetapir late-phase in the same cortical regions using a three-point scale (0 = normal, 1 = abnormal with minor plaques, 2 = abnormal with major plaques). We used SPM12 for semiquantitative analysis applying a ROI-based correlation analysis (considering precuneus as target region and normalized for the mean global binding), a covariance-analysis taking precuneus as target and a comparison of global DMN (default mode network). RESULTS: Inter-reader agreement was high (Cohen's kappa 0.762 for 18F-FDG, 0.775 for 18F-Florbetapir early-phase and 0.794 for late-phase). Regional visual scores of early-phase and 18F-FDG were significantly correlated (ρ = 0.867). Also ROI-based analysis, global brain visual analysis and DMN comparison revealed concordant results, especially at parietal and precuneus (p < 0.001). CONCLUSIONS: 18F-Florbetapir early-phase scans significantly correlate on quantitative and visual images with 18F-FDG-PET/CT scans, suggesting that amyloid tracer could be instead of 18F-FDG.

Prognostic Role of Pre-Treatment Metabolic Parameters and Sarcopenia Derived by 2-[18F]-FDG PET/CT in Elderly Mantle Cell Lymphoma.

The goal of this retrospective study was to analyze and compare the prognostic role of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (2-[18F]-FDG PET/CT) features and sarcopenia, estimated by CT of PET in elderly (≥65 years) Mantle Cell Lymphoma (MCL). We recruited 53 patients, who underwent pre-treatment 2-[18F]-FDG PET/CT and end-of-treatment PET/CT, and the main semiquantitative parameters were calculated. Sarcopenia was measured as skeletal muscle index (SMI, cm2/m2) and derived by low-dose PET/CT images at the L3 level. Specific cut-offs for SMI were calculated by receiver operator curve and divided by gender. Metabolic response was evaluated at end-of-treatment PET/CT, applying the Deauville score. Progression Free Survival (PFS) and Overall Survival (OS) were calculated for the whole population and for different subgroups, defined as per different sarcopenia cut-off levels. The specific cut-offs to define sarcopenia were 53 cm2/m2 for male and 45.6 cm2/m2 for female. Thirty-two (60%) patients were defined as sarcopenic. The 3-year and 5-year PFS rates were 29% and 23%, while the 3-year and 5-year OS rates were 43% and 33%. Metabolic response, total metabolic tumor volume (tMTV), total lesion glycolysis (tTLG) and sarcopenia were independent prognostic factors for PFS. Considering OS, no variable was significantly associated. Combination between PET features and sarcopenia may help to predict PFS.

Comparison between Two Different Scanners for the Evaluation of the Role of 18F-FDG PET/CT Semiquantitative Parameters and Radiomics Features in the Prediction of Final Diagnosis of Thyroid Incidentalomas.

The aim of this study was to compare two different tomographs for the evaluation of the role of semiquantitative PET/CT parameters and radiomics features (RF) in the prediction of thyroid incidentalomas (TIs) at 18F-FDG imaging. A total of 221 patients with the presence of TIs were retrospectively included. After volumetric segmentation of each TI, semiquantitative parameters and RF were extracted. All of the features were tested for significant differences between the two PET scanners. The performances of all of the features in predicting the nature of TIs were analyzed by testing three classes of final logistic regression predictive models, one for each tomograph and one with both scanners together. Some RF resulted significantly different between the two scanners. PET/CT semiquantitative parameters were not able to predict the final diagnosis of TIs while GLCM-related RF (in particular GLCM entropy_log2 e GLCM entropy_log10) together with some GLRLM-related and GLZLM-related features presented the best predictive performances. In particular, GLCM entropy_log2, GLCM entropy_log10, GLZLM SZHGE, GLRLM HGRE and GLRLM HGZE resulted the RF with best performances. Our study enabled the selection of some RF able to predict the final nature of TIs discovered at 18F-FDG PET/CT imaging. Classic semiquantitative and volumetric PET/CT parameters did not reveal these abilities. Furthermore, a good overlap in the extraction of RF between the two scanners was underlined.

Different glucose metabolism behavior relating to histotypes in synchronous breast cancers evaluated by [18F]FDG PET-CT.

Glucose metabolism is increased in most aggressive tumors and it is commonly evaluated by positron emission tomography-computed tomography (PET-CT) with 18F-fluorodeoxyglucose ([18F]FDG), measuring the Maximum Standardized Uptake Value (SUVmax) for the assessment. Particularly, it is known that breast cancer expresses different glucose metabolism inrelation to estrogen receptor (ER), progesterone receptor (PR), Ki67 score, tumor grading, tumor size, and Human Epidermal Growth Factor Receptor 2 (HER2). We present an interesting case of a woman with two different, synchronous breast cancers characterized by different glucose metabolism, according to literature knowledge.

Incidental Finding of Testicular Seminoma by 18F-Choline PET/CT in a Prostate Cancer Patient.

ABSTRACT: An 80-year-old man with a history of prostate cancer, treated with radical prostatectomy and bilateral obturator nodal dissection, underwent an 18F-choline PET/CT because of biochemical recurrence. The scan revealed an intense focal uptake in the right testicle. A subsequent orchifunicumlectomy demonstrated the presence of a classic seminoma. At present, 18F-FDG PET/CT is useful for initial staging of testicular cancer and determining the viability of residual masses >3 cm after completion of treatment, especially in patients with seminoma.

Prognostic Role of "Radiological" Sarcopenia in Lymphoma: A Systematic Review.

Sarcopenia is considered to be a poor prognostic factor for several oncological diseases; however, some promising results for lymphoma are now available. The definition of sarcopenia is mainly based upon muscle strength, quantity or quality and physical performance, but some imaging tools (such as CT) have been introduced to estimate quantitatively the muscle areas as an indirect expression of sarcopenia. Our aim was to perform a systematic review on the prognostic role of "radiological" sarcopenia in lymphoma. A comprehensive online search of PubMed/MEDLINE, Embase and Cochrane library databases was conducted up to June 2021 to find relevant articles on the prognostic role of sarcopenia in lymphoma measured by CT. In total, 25 articles with a total of 4454 patients were included. Diffuse large B-cell lymphoma was the most common lymphoma variant studied, followed by Hodgkin lymphoma. Skeletal muscle area (SMA) was defined as the parameter to distinguish between sarcopenic and nonsarcopenic lymphoma on CT scans and was usually measured at the level of the third lumbar vertebra. In the literature, different thresholds are used to define sarcopenia, related to the features of patients included in the studies. Despite this heterogeneity, in most cases, sarcopenia was demonstrated to be significantly correlated with OS and PFS. Sarcopenia measurement with CT (high dose or low dose) is a safe, accurate and precise method.

18F-FDG PET/CT for the evaluation of male breast cancer: a systematic review.

BACKGROUND: In the last years, some studies on the usefulness of 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) for the evaluation of male breast cancer (MBC) have been produced. The aim of this review is to analyze the usefulness of 18F-FDG PET/CT and its diagnostic performances for the assessment of MBC. METHODS: A wide literature search of the PubMed/MEDLINE, Scopus, Embase and Cochrane library databases was made to find relevant published articles on the role of 18F-FDG PET/CT for the evaluation of MBC. Moreover, quality assessment including the risk of bias and applicability concerns was carried out using QUADAS-2 evaluation. RESULTS: The comprehensive computer literature search revealed 3178 articles. On reviewing the titles and abstracts, 3170 articles were excluded because the reported data were not within the field of interest and finally eight studies were included in the review, for a total of 176 male patients. The studies considered revealed high diagnostic accuracy of 18F-FDG PET/CT for the evaluation of MBC both at staging and restaging of disease. Moreover, its added values compared to conventional imaging are starting to emerge and insight into its controversial prognostic importance is growing. CONCLUSION: Despite some limitations affecting our review, 18F-FDG PET/CT seems to be a valuable tool to assess MBC. Further research studies are required to better underline the role of hybrid imaging with 18F-FDG for the evaluation of MBC, especially in comparison with female breast cancer.

18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Interpretation Criteria for the Assessment of Therapeutic Response in Patients with Advanced Stage of Lung Cancer: Inter-Reader Reliability, Accuracy, and Survival Outcomes.

Aim: 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) is useful in the evaluation of lung cancer (LC), both for staging and therapy assessment. However, for the evaluation of treatment response, shared criteria are not available. We proposed a 3-point score, similar to Deauville-score and compared its diagnostic accuracy with Hopkins criteria for the evaluation of treatment response in LC to validate a qualitative and simpler interpretation system. Methods: We retrospectively included 93 patients with advanced stage (III-IV) LC who underwent 18F-FDG-PET/CT after first-line treatment. Positron emission tomography/computed tomography (PET/CT) scans were interpreted according to a 3-point scale-like Deauville score criteria (score 1 = uptake lower than blood-pool activity; score 2 = uptake higher than blood-pool but lower than liver activity; score 3 = uptake higher than liver). Inter-reader variability was assessed using percent agreement and kappa statistics. Kaplan-Meier plots with a Mantel-Cox log-rank test were performed, considering death as the endpoint. Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of like Deauville-like score criteria were 82,76% (95% confidence interval [CI] 70.5%-91.4%), 80% (95% CI 28.3%-99%), 97.9% (95% CI 89.2%-99.6%), 28.6%(95% CI 16.38%-44.9%), and 82.5% (95% CI 70.9-90.9%), respectively. Applying Hopkins criteria score we obtained sensitivity, specificity, PPV, NPV, and accuracy of 81% [95% CI 68.6%-90.1%), 100% (95% CI 47.2-100%), 100% (95% CI %), 31.3% (95% CI 21.0%-43%), and 82.5%(95% CI 70.9%-90.9%), respectively. There was a high agreement between the two readers both using Hopkins criteria (k = 0.912) and like-Deauville-score criteria (k = 0.956). Applying 3-point-scale criteria, patients with positive PET/CT after therapy had significantly shorter lower survival (P = 0.0021). Conclusion: The application of 3-point scale criteria for posttherapy assessment in patients with advanced stage of LC represents an easy and reproducible method with optimal inter-observer agreement and great PPV and accuracy.

Prognostic factors in children and adolescents with differentiated thyroid carcinoma treated with total thyroidectomy and RAI: a real-life multicentric study.

PURPOSE: This multicentric study aimed to investigate the main prognostic factors associated with treatment response at 1 year after radioactive iodine therapy (RAIT) and the last disease status in pediatric patients affected by differentiated thyroid carcinoma (DTC). MATERIALS AND METHODS: In the period 1990-2020, all consecutive patients ≤ 18 years from six different centers were retrospectively included. Patients were classified as low, intermediate, and high risk for persistence/recurrence. The response to RAIT was evaluated and scored 1 year later according to 2015 ATA guidelines. Moreover, at the last follow-up, the disease status was evaluated and dichotomized as no evidence of disease (NED) or persistent disease. RESULTS: Two hundred and eighty-five patients (197 female, 88 male; mean age 14.4 years) were recruited. All, except nine, underwent near-total thyroidectomy followed by RAIT. One-year after first RAIT, 146/276 (53%) patients had excellent response, 37/276 (14%) indeterminate response, and 91/276 (33%) incomplete response. One-year after RAIT, children with excellent response had significantly lower stimulated thyroglobulin (sTg) compared to not excellent group (median sTg 4.4 ng/ml vs 52.5 ng/ml, p < 0.001). ROC curve showed sTg higher than 27.2 ng/ml as the most accurate to predict 1-year treatment response. After a median follow-up of 133 months, NED was present in 241 cases (87%) while persistent disease in 35 (13%). At multivariate analysis, sTg and 1-year treatment response categories were both significantly associated with the last disease status (p value 0.023 and < 0.001). CONCLUSIONS: In pediatric DTC, sTg is significantly associated with 1-year treatment response and final outcome. However, 1-year response is the principal prognostic factor able to predict pediatric DTCs outcome.

COVID-19 Vaccination Manifesting as Unilateral Lymphadenopathies Detected by 18F-Choline PET/CT.

ABSTRACT: A 79-year-old man with a history of prostate adenocarcinoma treated with prostatectomy underwent 18F-FCH PET/CT for restaging purpose, which was negative for relapse but showed the presence of choline-positive lymph nodes in the left axilla. The patient underwent a COVID-19 vaccination in the left arm 6 days prior. Thus, PET/CT findings were considered as inflammatory lymph nodes. With the current drive of global COVID-19 immunization, this case underlines the importance of knowing vaccination history to interpret correctly the findings and to avoid false-positive reports.

Clinical and prognostic 18F-FDG PET/CT role in recurrent vulvar cancer: a multicentric experience.

PURPOSE: The aim of this retrospective multicentric study was to investigate the diagnostic performance, the prognostic value and the impact of 18F-FDG PET/CT on treatment decision-making in patients with suspected recurrent vulvar cancer (VC). MATERIALS AND METHODS: Sixty-three patients affected by VC performed 18F-FDG-PET/CT for restaging purposes in case of suspected clinical and/or radiological recurrence. Histopatology results if available and/or clinical-imaging follow-up for at least 12 months were considered as reference standard. The diagnostic accuracy and the clinical impact of 18F-FDG PET/CT were investigated. Progression free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier curves. RESULTS: Fifty-two (82.5%) PET/CT showed the presence of recurrence, while the remaining 11 (17.5%) were negative. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT were 100% (95%CI 93-100%), 92% (95%CI 62-100%), 98% (95%CI 89-99%), 100% and 98% (95%CI 92-100%). A relevant impact of 18F-FDG PET/CT imaging was registered in 28 cases: in 12 cases moving from local therapy to chemotherapy due to the recognition of disseminate localizations; in 10 showing the site of recurrence in presence of negative conventional imaging, and in 6 cases confirming to be true negative and avoiding unnecessary therapies. Beside advanced age and HPV status, a positive restaging 18F-FDG PET/CT scan was significantly correlated with shorter PFS and OS compared to negative scan (p < 0.001). CONCLUSIONS: 18F-FDG PET/CT demonstrated to be an accurate tool in the assessing of recurrent VC with high sensitivity and specificity and with a significant impact on clinical decision-making. Restaging 18F-FDG PET/CT findings were associated with survival.

Cardiac lymphoma with early response to chemotherapy: A case report and review of the literature.

Cardiac tumors are rare and benign masses account for the most part of the diagnosis. When malignant cancer is detected, primary or secondary cardiac lymphoma are quite frequent. Cardiac lymphoma may present as an intra or peri-cardiac mass or, rarely, it may diffusely infiltrate the myocardium. Although often asymptomatic, patients can have non-specific symptoms. Acute presentations with cardiogenic shock, unstable angina, or acute myocardial infarction are also described. Modern imaging techniques can help the clinicians not only in the diagnostic phase but also during administration of chemotherapy. A multidisciplinary counseling and serial multi-parametric assessment (echocardiography, cardiac troponin) seem to be the most effective approach to prevent possible fatal complications (i.e., cardiac rupture). Currently, only chemo- and radiotherapy are available options for treatment, but the prognosis remains poor. This is a case of secondary cardiac lymphoma presenting as a mediastinal mass with large infiltration of the heart and the great vessels with a good improvement after only one cycle of chemotherapy. It demonstrates the importance of an early diagnosis to modify the natural history of the disease.

Role of 18F-FDG PET/CT Radiomics Features in the Differential Diagnosis of Solitary Pulmonary Nodules: Diagnostic Accuracy and Comparison between Two Different PET/CT Scanners.

The aim of this retrospective study was to investigate the ability of 18 fluorine-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) metrics and radiomics features (RFs) in predicting the final diagnosis of solitary pulmonary nodules (SPN). We retrospectively recruited 202 patients who underwent a 18F-FDG-PET/CT before any treatment in two PET scanners. After volumetric segmentation of each lung nodule, 8 PET metrics and 42 RFs were extracted. All the features were tested for significant differences between the two PET scanners. The performances of all features in predicting the nature of SPN were analyzed by testing three classes of final logistic regression predictive models: two were built/trained through exploiting the separate data from the two scanners, and the other joined the data together. One hundred and twenty-seven patients had a final diagnosis of malignancy, while 64 were of a benign nature. Comparing the two PET scanners, we found that all metabolic features and most of RFs were significantly different, despite the cross correlation being quite similar. For scanner 1, a combination between grey level co-occurrence matrix (GLCM), histogram, and grey-level zone length matrix (GLZLM) related features presented the best performances to predict the diagnosis; for scanner 2, it was GLCM and histogram-related features and metabolic tumour volume (MTV); and for scanner 1 + 2, it was histogram features, standardized uptake value (SUV) metrics, and MTV. RFs had a significant role in predicting the diagnosis of SPN, but their accuracies were directly related to the scanner.

Minimal Extrathyroidal Extension in Predicting 1-Year Outcomes: A Longitudinal Multicenter Study of Low-to-Intermediate-Risk Papillary Thyroid Carcinoma (ITCO#4).

Background: The role of minimal extrathyroidal extension (mETE) as a risk factor for persistent papillary thyroid carcinoma (PTC) is still debated. The aims of this study were to assess the clinical impact of mETE as a predictor of worse initial treatment response in PTC patients and to verify the impact of radioiodine therapy after surgery in patients with mETE. Methods: We reviewed all records in the Italian Thyroid Cancer Observatory database and selected 2237 consecutive patients with PTC who satisfied the inclusion criteria (PTC with no lymph node metastases and at least 1 year of follow-up). For each case, we considered initial surgery, histological variant of PTC, tumor diameter, recurrence risk class according to the American Thyroid Association (ATA) risk stratification system, use of radioiodine therapy, and initial therapy response, as suggested by ATA guidelines. Results: At 1-year follow-up, 1831 patients (81.8%) had an excellent response, 296 (13.2%) had an indeterminate response, 55 (2.5%) had a biochemical incomplete response, and 55 (2.5%) had a structural incomplete response. Statistical analysis suggested that mETE (odds ratio [OR] 1.16, p = 0.65), tumor size >2 cm (OR 1.45, p = 0.34), aggressive PTC histology (OR 0.55, p = 0.15), and age at diagnosis (OR 0.90, p = 0.32) were not significant risk factors for a worse initial therapy response. When evaluating the combination of mETE, tumor size, and aggressive PTC histology, the presence of mETE with a >2 cm tumor was significantly associated with a worse outcome (OR 5.27 [95% confidence interval], p = 0.014). The role of radioiodine ablation in patients with mETE was also evaluated. When considering radioiodine treatment, propensity score-based matching was performed, and no significant differences were found between treated and nontreated patients (p = 0.24). Conclusions: This study failed to show the prognostic value of mETE in predicting initial therapy response in a large cohort of PTC patients without lymph node metastases. The study suggests that the combination of tumor diameter and mETE can be used as a reliable prognostic factor for persistence and could be easily applied in clinical practice to manage PTC patients with low-to-intermediate risk of recurrent/persistent disease.

18F-FDG PET and PET/CT for the evaluation of gastric signet ring cell carcinoma: a systematic review.

BACKGROUND: In the last years, 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) has demonstrated its utility for the evaluation of gastric cancer; however, considering some histotypes such as gastric signet ring cell carcinoma (GSRCC) the results are limited. The aim of this review is to analyze the diagnostic performance of 18F-FDG PET and PET/CT for the assessment of GSRCC. METHODS: A wide literature search of the PubMed/MEDLINE, Scopus, Embase and Cochrane library databases was made to find relevant published articles about the diagnostic performance of 18F-FDG PET or PET/CT for the evaluation of GSRCC. RESULTS: The comprehensive computer literature search revealed 179 articles. On reviewing the titles and abstracts, 162 articles were excluded because the reported data were not within the field of interest. Nine studies were included in the review and references were also screened for additional articles. Finally, 26 articles were selected and retrieved in full-text version. CONCLUSION: Despite some limitations affect our review, GSRCC seems to have low 18F-FDG uptake, and therefore 18F-FDG PET or PET/CT reveals impaired sensitivity for its evaluation. However, a correlation between 18F-FDG uptake and some clinico-pathologic features (such as stage, depth of invasion, size and presence of nodal metastasis) has been demonstrated. Besides, a possible prognostic role of PET/CT features is starting to emerge.