Pulmonary Epstein-Barr virus-associated smooth muscle tumor after kidney transplantation: two case reports with review of differential diagnosis.

Pulmonary nodules are a common complication in solid organ transplant recipients, and may have various underlying causes, with Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT) being one of them. Given the rarity of this entity, we describe the diagnosis and therapeutic interventions for post-transplant EBV-SMT in two individuals. Both cases involved female patients who were diagnosed with multiple pulmonary nodules 60 months and 116 months, respectively, after receiving living-related kidney transplantation. Pathological examination revealed a spindle cell tumor, with immunophenotype and EBV in situ hybridization supporting the diagnosis of EBV-SMT. After diagnosis, these two patients underwent intervention by decreasing their intake of immunosuppressants. As of the latest follow-up, the patients' lesion size remained stable, and their overall condition was favorable. We also reviewed literature about the morphological and molecular pathological features of EBV-SMT and highlighted the diagnosis and differential diagnosis of pulmonary spindle cell lesions especially in the setting of immunosuppression.

I-125 seed-loaded versus normal stent insertion for obstructive esophageal cancer: a meta-analysis.

INTRODUCTION: Malignant esophageal obstruction is usually caused by esophageal and other chest cancers. More than 80% of cases of obstructive esophageal cancer (OEC) have lost the chance of curative resection. Stent insertion is a first-line palliative approach used to treat incurable OEC. AIM: To gauge the relative clinical efficacy of I-125 seed-loaded stent (ISS) versus normal stent (NS) insertion as a treatment for OEC. MATERIAL AND METHODS: Querying of the PubMed, Embase, and Cochrane Library databases was conducted to find all relevant studies published up to November 2020. The meta-analysis was undertaken using RevMan v5.3. RESULTS: We identified 158 studies initially, eight (4 randomized controlled trials and 4 retrospective studies) of which were used in this meta-analysis. We found that the two groups exhibited the comparable pooled Δdysphagia scores (MD = 0.02; p = 0.80), stent restenosis rates (OR = 0.97; p = 0.89), stent migration rates (OR = 0.81; p = 0.63), severe chest pain rates (OR = 1.05; p = 0.81), hemorrhage rates (OR = 1.53; p = 0.16), aspiration pneumonia rates (OR = 0.72; p = 0.38), and fistula formation rates (OR = 1.47; p = 0.44). The pooled time-to-restenosis and survival were both significantly longer in the ISS group (p = 0.04 and < 0.0001, respectively). Significant heterogeneity was detected in the endpoints of Δdysphagia scores and survival (I2 = 73% and 86%, respectively). Funnel plot analysis indicated an absence of publication bias related to the selected study endpoints. CONCLUSIONS: For patients with OEC, our meta-analysis indicated that ISS insertion could provide longer stent patency and survival than NS insertion.

Pitfalls in positron emission tomography/computed tomography imaging: causes and their classifications.

OBJECTIVE: To describe the pitfalls in positron emission tomography/computed tomography (PET/CT) imaging and classify them according to the principles of their generation. METHODS: We summarized retrospectively the 18F-fluorodeoxyglucose (FDP) PET/CT imaging pitfalls through reviewing the PET/CT images of 872 patients. The pitfalls were divided into artifacts and infrequent physiological uptake, and the artifacts were further classified according to their causes. Meanwhile, we calculated the incidences of various pitfalls. Whether the PET/CT pitfalls influenced the diagnostic decision was analyzed. The appearances of pitfalls in PET were also described. RESULTS: Pitfalls could be found in PET/CT images of 684 (78.4%) patients. Artifacts were found in 664 (76.15%) patients, and could be classified into self-factor artifacts and equipment- or technology-related artifacts. Among self-factor artifacts, respiratory motion (57.5%), postprandial or hyperglycemia artifacts (2.41%), and metal or high density matter artifacts (1.38%) were frequent. As for equipment- or technology-related factors, injection point outleakage or radiotracer contamination (13.88%) and truncation artifacts (1.83%) were most common ones. Infrequent physiological FDG uptakes, including fatty uptake, endometrial uptake, and bilateral breast feeding period uptake, were found in 20 (2.29%) patients. Among all pitfalls, the artifacts in 92 (13.4%) patients and infrequent physiological uptakes in 6 (0.88%) patients affected the diagnostic results. Artifact images in PET could be described as hot or cold area and the images of infrequent physiological uptake were always shown as hot area. CONCLUSIONS: The incidence of pitfall in PET/CT imaging was high and the causes of pitfalls are various. Among all causes that artifacts generated, respiratory motion is the most common. Some pitfalls may disturb clinical physicians' decision, so it is important to recognize artifacts and physiological uptake, and distinguish them from pathological uptakes.

Evaluation of lung lesions using FDG gamma-camera PET equipped with a one-inch crystal.

The aim of this study was to evaluate the clinical value of 18-fluorodeoxyglucose (FDG) imaging with gamma-camera positron emission tomography (GCPET) equipped with a one-inch crystal for diagnosing lung lesions and determining the stage of non-small cell lung cancer (NSCLC) in regions with a high prevalence of inflammatory disease and tuberculosis. FDG-GCPET was used to examine 103 patients with suspected malignant lesions in the lung. The results of FDG-GCPET and conventional workup (CWU) including computed tomography (CT), ultrasonography and radionuclide bone scintigraphy were compared. The final diagnosis was based on the results of a histological analysis or follow-up of at least six months. The results showed 82 patients with malignant and 21 patients with benign lesions. If a lesion to background ratio > or = 2.0 was used as the threshold, then the diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of FDG-GCPET for NSCLC were 93.9, 57.1, 86.4, 89.5 and 70.6%, respectively. In 36 patients who underwent open-chest surgery, the diagnostic positive values of FDG-GCPET and CT for lymph-node involvement were 85% (17/20) and 65% (13/20), respectively. The diagnostic sensitivity, specificity, accuracy, PPV and NPV of FDG imaging were 85, 81.3, 83.3, 85 and 81.3%, respectively compared to the CT values of 65, 75, 69.4, 76.5 and 63.2%, respectively (NS). For the evaluation of distant metastases, 31 true-positive patients were identified during the follow-up. FDG imaging correctly identified 28 patients compared to 25 by CWU. In conclusion, FDG imaging with GCPET equipped with a one-inch crystal revealed a high lesion detection capability but a low level of clinical effectiveness for differentiating between malignant and benign lesions in the lung in regions with a high prevalence of inflammatory disease and tuberculosis. For N and M staging of NSCLC, this method may provide additional data that are not available from the CWU.

Sustained and diffuse 131I avid bone metastases with low thyroglobulin levels in a patient with papillary thyroid carcinoma.

A 63-year-old man with papillary thyroid carcinoma (PTC) and bone metastases was treated with 131I residual thyroid ablation (RTA) and 2 repeated post-ablation 131I therapies after total thyroidectomy. 131I whole-body scans (WBS) demonstrated sustained and diffuse 131I avid bone metastases, accompanied by persistent very low thyroglobulin (Tg) levels and negative antithyroglobulin antibody (TgAb) in post-ablation 131I therapies in hypothyroid state after levothyroxine withdrawal. The spread of bone metastases were found on the last therapeutical 131I WBS. The benefit of 131I therapy after levothyroxine withdrawal should be weighed even if the metastases are 131I avid in poorly differentiated thyroid carcinoma.

Posterior nutcracker syndrome associated with interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein.

Various anatomic anomalies have been considered the causes of nutcracker syndrome (NCS). Posterior NCS refers to the condition, in which vascular narrowing was secondary to the compression of the retroaortic left renal vein while it is crossing between the aorta and the vertebral column. Here, we report an unusual case of posterior NCS associated with a complicated malformation of the interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein, diagnosed by both color Doppler ultrasonography and CT angiography.

Application of FDG-PET for detection of malignant lesions in patients with elevated blood tumor markers but without a history of malignancy.

The aim of this study was to evaluate the clinical application of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging for the detection of malignant lesions. A total of 132 patients with increased levels of blood tumor markers but without a prior history of malignancy were examined. The results of FDG-PET and conventional work-up (CWU) including computed tomography (CT), ultrasonography, radionuclide bone scintigraphy and endoscopy were compared. The final diagnosis was based on pathological evidence, other medical imaging results and a follow-up of at least 6 months. There were 61 patients with malignant lesions and 71 without (benign lesions, n=35; healthy individuals, n=36). The average number of elevated tumor markers and the average increase in these tumor markers were greater in the malignant group than in the non-malignant group. FDG-PET imaging revealed that the maximum standardized uptake value (SUVmax) of the major lesion in patients with malignant (n=61) and benign (n=35) tumors was not significantly related to increased levels of tumor markers (r=0.10, p<0.05). In patients with malignant lesions and an SUVmax ≥3.0, the diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FDG-PET were 95.1, 83.1, 88.6, 82.9 and 95.2%, respectively. CWU identified 61 (100%) true-positive patients. No statistically significant differences in sensitivity were observed between the results of FDG-PET and CWU (p>0.05). In 36 healthy subjects without abnormal CWU findings, no abnormal FDG accumulation was revealed by FDG-PET imaging. In conclusion, FDG-PET imaging is a valuable tool for the detection of malignant lesions in patients with increased levels of blood tumor markers but without a history of malignancy. It is therefore reasonable to apply FDG-PET imaging in situations in which the results of CWU are inconclusive, or when patients wish to limit the number of examinations they must undergo.