Unusual Metastatic Sites in Malignant Phyllodes Tumor Detected on FDG PET/CT.

Phyllodes tumor is a rare fibroepithelial neoplasm of the breast. This tumor tends to spread by hematogenous route, with common metastatic sites in the lungs, bones, and liver. Metastases to the pleura, stomach, pancreas, kidneys, and adrenal gland are rare. We present a case of a 52-year-old lady with malignant phyllodes tumor of breast undergone local tumor resection, followed by solitary lung metastasis with lobectomy, and subsequently diagnosed of multiple new metastatic sites in pleura, stomach, pancreas, kidneys, adrenal gland, and bone detected on 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography within 2 years.

Retrospective study of qualitative assessment in detecting synchronous and metachronous malignancies in adult cancer patients by 18F-FDG PET/CT.

OBJECTIVES: The study aimed to evaluate the frequency of incidental suspicious lesions detected by flourine-18 fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) scans done for staging or restaging in adult cancer patients. We further determined the detection rate of synchronous and metachronous malignancies in these suspicious lesions after further investigations. MATERIALS AND METHODS: This retrospective analysis evaluated the consecutive patients with 18F-FDG PET/CT scans done in Queen Elizabeth Hospital (QEH), Hong Kong between July 2021 and June 2022. The adult cancer patients who underwent staging or restaging 8F-FDG PET/CT were included while the remaining were excluded. Patients' demographics, primary cancer type, tumor markers, and pathological analyses for the incidental suspicious lesions were reviewed to establish the detection rate of synchronous and metachronous malignancies. RESULTS: A total of 2054 patients fulfilled inclusion criteria with age ranging from 18 to 93 years old. Out of the 2054 patients, 304 (14.8%) were found to have incidental suspicious lesions. Of these, 206 patients (67.8%) underwent further investigations including pathological analyses. Subsequently, 84 of these 206 patients (40.8%) had pathologically proven synchronous or metachronous malignancies. CONCLUSION: The detection rate of incidental suspicious lesions in adult cancer patients who underwent 18F-FDG PET/CT scans for staging or restaging was 14.8% and the rate of synchronous and metachronous malignancies in these suspicious lesions was 40.8%. The treatment plan of these patients may potentially be altered, which should be included in the cost-benefit analysis of using this imaging modality.

Giant parathyroid adenoma and hungry bone syndrome in MEN1 syndrome: A case report.

An 18-year-old male with multiple endocrine neoplasm type 1 (MEN1) syndrome presented with hyperparathyroidism. Parathyroidectomy was performed. Patient complained of bone pain afterwards, multiple imaging modalities revealed features of osteitis fibrosa cystica and biochemical profile showed features of hungry bone syndrome. Incidental suspicious pancreatic lesion was initially revealed by 18F-FDG PET/CT scan while MRI further characterized the possibility of insulinoma. Ultimately, the patient was diagnosed of MEN1 syndrome by genetic test. This case report demonstrates the utilization of various imaging modalities such as ultrasound, Tc99m-sestamibi parathyroid scintigraphy, bone scintigraphy, CT, PET/CT and MRI, which leads to ultimately the diagnosis of MEN1 syndrome.

The diagnostic performance of 18 fluorine-fluorodeoxyglucose PET for brain metastases: a systematic review and meta-analysis.

INTRODUCTION: Brain metastases may manifest as hypermetabolism or hypometabolism compared with normal brain activity on 18 fluorine-fluorodeoxyglucose PET ( 18 F-FDG PET). We aim to undertake a systematic review and meta-analysis to determine the diagnostic accuracy of FDG PET for detecting brain metastases from different extracranial primary cancers. METHODS: PubMed and EMBASE were searched systematically. Study selection and quality assessment were performed independently by two authors. Meta-analysis was performed using a bivariate random-effects model. Subgroup analysis and meta-regression would be performed if heterogeneity was found. RESULTS: A total of 2227 patients from 11 studies were included in the review and analysis. Using the bivariate random-effects model, summary patient-based sensitivity and specificity for all 11 studies were estimated to be 0.440 [95% confidence interval (CI)] 0.295-0.597) and 0.997 (95% CI, 0.977-1.000). In view of significant between-study heterogeneity ( I2  = 74.0% for sensitivity and I2  = 67.3% for specificity), subgroup analyses were performed. Meta-regression showed significantly higher patient-based summary sensitivity for the three better-quality studies (a total of 1037 patients) with satisfactory index test (counting both hypermetabolism and hypometabolism as positive index test) and satisfactory reference standards (other imaging and clinical follow-up) compared with other included studies [0.735 (95% CI, 0.601-0.836) vs 0.304 (95% CI, 0.223-0.400), P value = 0.000]. CONCLUSION: Our systematic review and meta-analysis showed that FDG PET has overall limited sensitivity and excellent specificity in the detection of brain metastases from extracranial primary cancers. Importantly, subgroup analyses showed that the sensitivity can be significantly improved by raising awareness of asymmetrical hypometabolism. Further studies are warranted to assess the benefits of including the brain in FDG PET studies for all or certain groups of oncological patients.

A case series of FDG PET scan: hypometabolic lesions that matter in oncology.

Interpretation of FDG PET images in oncology patients is in general a visual exercise of search for focal increased uptake (hypermetabolism). However, in some cases, hypometabolism (focal decreased uptake) can matter as much as hypermetabolism. We report three cases of FDG PET studies for oncological indications. All of them showed focal hypometabolic lesions suspicious of metastases. The diagnoses were then supported either by histological proof and/or follow-up imaging studies. The importance of being alert to both focal hypermetabolism and focal hypometabolism when interpreting FDG PET images is underscored.

A case of dermatopathic lymphadenitis mimicking lymphoma on 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging.

This case report illustrates a rare case of dermatopathic lymphadenitis with interval 18F-fluorodeoxyglucose positron emission tomography/ computed tomography performed. The clinical presentation, imaging, and histological findings are described. We discuss the diagnostic challenges in this case.

Semi-quantitative assessment optimized the grading of pulmonary aspiration on salivagram in children.

OBJECTIVE: Salivagram is one of the imaging modalities to detect pulmonary aspiration in children. This study aims to optimize the classification of pulmonary aspiration detected by salivagram with a semi-quantitative analytical method. METHODS: This is a retrospective study involving 737 patients (471 males, 266 females; aged 1 month to 8 years; mean age 5.3 months, median age 3.0 months old) with suspected pulmonary aspiration, who had salivagram done between January 2018 and June 2019. Positive cases were divided into 10 groups (Grade 1, R2, L2, R2L2, R3, L3, R3L2, R2L3, R3L3, and 4) according to the scintigraphic findings. Aspiration index was determined as the ratio of the count in the respiratory tract to the total count in the image field of view and compared among different groups using the receiver operating characteristics (ROC) curve analysis. RESULTS: A total of 180 cases had positive scintigraphic findings of various grades of aspiration (24.4%, 180/737). There is a high consistency among the two independent nuclear medicine physicians involved in the study, in determining both the disease gradings (κ = 0.919;95% CI: 0.915-0.923) and aspiration index (ICC = 0.994;95% CI: 0.993-0.996). There is no significant difference (p > 0.05) in aspiration index among the gradings in "mild" group (grade 1, R2, L2, L2R2), and "moderate" group (grade R3, R3L2, R3L3). After dividing the different grades into "mild", "moderate" and "severe" groups, the aspiration index of "mild" group is 4.40 ± 2.01, that of "moderate" group is 16.43 ± 8.20, and that of "severe" group is 46.94 ± 14.81. Difference in groups was statistically significant (p < 0.0001). In ROC curve analysis, AUC of "mild" and "moderate" groups is 0.970 and that of "moderate" and "severe" groups is 0.943; the cut-off value with highest diagnostic efficiency is 6.75 between "mild" and "moderate" groups and 38.00 between "moderate" and "severe" groups. CONCLUSIONS: We introduced a semi-quantitative analytical method in pulmonary aspiration on salivagram, to optimize and supplement to the current classification of pulmonary aspiration.

An update on the role of 18F-FDG-PET/CT in major infectious and inflammatory diseases.

For decades, conventional nuclear medicine techniques have been utilized for the assessment of many infectious and inflammatory diseases. Most of these techniques have limitations such as the relatively low spatial resolution, being time consuming and low sensitivity or specificity. In recent years, FDG-PET/CT has shown promising role in the management of such diseases. An expanding set of studies illustrate the multifarious roles of FDG-PET/CT in the assessment of these conditions, both systemic diseases and more regional. Specifically, PET can provide vital information at a molecular level and consequently detect the disease activity at their earliest manifestation. With the continuing research on the diagnosis and treatment monitoring of patients with infectious and inflammatory diseases, the role of PET/CT can be further extended.

Massive pericardial effusion: A rare and easily missed finding in myocardial perfusion scintigraphy.

A 72-year-old gentleman underwent myocardial perfusion scintigraphy (MPS) for sinus tachycardia of unknown cause. Baseline electrocardiography (ECG) showed sinus tachycardia and electrical alternans. Thallium-201 stress-redistribution MPS was performed with dipyridamole stress. On the raw projection images, a photopenic "halo" was noted surrounding the heart. Reconstructed slices showed small left ventricle with no obvious perfusion defect. Review of single-photon emission computed tomography/computed tomography images showed suspected large pericardial effusion. The patient was admitted and Echocardiography showed significant circumferential pericardial effusion with early tamponade effect. Subsequent bedside pericardiocentesis aspirated 800 ml blood-stained fluid and the cytology yielded metastatic adenocarcinoma with features suggestive of pulmonary primary. Pericardial effusion is a rare finding in MPS. Finding of a "halo" around the heart should raise suspicion on the presence of pericardial effusion and confirmatory investigation such as ECG may be warranted.

The Pearl of FDG PET/CT in Preoperative Assessment of Patients with Potentially Operable Non-Small-Cell Lung Cancer and its Clinical Impact.

The aim of this retrospective study is to evaluate the clinical impact and efficacy of fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) on management decisions for patients suffering from clinically operable non-small-cell lung cancer (NSCLC). A retrospective review of 186 potentially operable NSCLC patients who underwent whole-body PET/CT examination in 2012 was performed. The patients were further analyzed via the electronic patient record (ePR) system for relevant findings. Overall change in management was assigned if a patient avoided unnecessary surgery due to disease upstaging or if a patient underwent further neoadjuvant treatment or investigation before the curative surgery. Of all 186 subjects, 65 (34.9%) became inoperable after PET/CT due to disease upstaging. The remaining 121 (65.1%) of patients remained operable after PET/CT examination. Nineteen out of 121 potentially operable patients did not receive curative surgery eventually, as 11 patients had poor clinical condition and 8 patients refused surgery. One hundred two out of 186 (54.8%) patients received curative operation following PET/CT. Among these 102 individuals, 97 patients (95%) proceeded to surgery without further neoadjuvant treatment or other investigatory procedures. Of the remaining 5 patients, 4 (3.9%) received neoadjuvant treatment and 1 (1.0%) had further investigation after PET/CT. Seventy of the 186 (37.6%) patients underwent changes in management plans after PET/CT study. Out of the 186 individuals, a subgroup of 141 (75.8%) patients underwent dedicated CT thorax before PET/CT examination. Forty-seven (33.3%) patients had avoided futile surgery due to disease upstaging. Fifty-one of the 141 (36.2%) patients underwent changes in management plans after PET/CT. PET/CT had great clinical impact, with significant reduction of futile curative surgery.

Promising Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Human Immunodeficiency Virus Associated Non-Hodgkin's Lymphoma.

This case report explores the potential role of FDG PET/CT in HIV -associated systemic non-Hodgkin's lymphoma (HIV-NHLs). In our locality, there are a cumulative total of 5523 reported HIV infections cases since 1984. We reported a case of HIV-related Burkitt's lymphoma (BL) and a case of diffuse large B-cell lymphoma (DLBCL) that underwent PET/CT examination in our PET centre. In HIV-NHLs patients, we must be reminded that not all hypermetabolic foci represent lymphomatous lesions. There is a close correlation between the pattern of lymphoid tissue activation in FDG PET/CT and HIV progression in patients without HIV-related malignancy. The unique patterns of lymphoid tissue activation observed in HIV-infected patients have great clinical implications. Secondly, HIV-infected patients are prone to suffer from opportunistic infections due to immunosuppression, particularly in those with high levels of HIV viral loads. FDG PET/CT cannot reliably differentiate metabolic active lymphoma from other benign diseases such as inflammation in the context of low CD4 count and high viral loads. In those cases, benign markedly hypermetabolic foci can be erroneously interpreted as lymphoma, particularly in those normal-sized lymph nodes. Furthermore, FDG PET/CT may be useful for assessing the efficacy of HAART in suppressing HIV replication and detecting its complication such as lipodystrophy. FDG PET/CT may play a potential useful role in staging and management of HIV -associated systemic non-Hodgkin's lymphoma. Plasma variables such as viral loads and CD4 count must be taken into account during image interpretation. FDG PET/CT as a potential useful tool for diagnosis, treatment response assessment and disease relapse detection in HIV -associated systemic non-Hodgkin's lymphoma worth to be further explored.

Prevalence of detecting unknown cerebral metastases in fluorodeoxyglucose positron emission tomography/computed tomography and its potential clinical impact.

To determine the prevalence of incidental finding of unknown cerebral metastases and explore the clinical impact of detecting unknown brain metastases among individuals underwent whole body fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with brain included in field of view. A retrospective review of 1876 patients who underwent whole body PET/CT examination in our clinical PET center for oncological evaluation from January 2009 to September 2009 was performed. The total number and prevalence of unknown brain metastases detected by PET/CT were calculated. Patients diagnosed with cerebral metastases by PET/CT were further analyzed via the electronic patient record system for relevant clinical and radiological findings. Positive predictive value of PET/CT for the diagnosis of cerebral metastases was calculated with reference to contrast enhanced magnetic resonance imaging (MRI) or contrast enhanced CT. Of the 1876 subjects, 71 patients (3.8%) were diagnosed with cerebral metastases by PET/CT. 31 patients were already diagnosed with brain metastases before PET/CT. Among the 40 patients with unknown brain metastasis, 24 (60.0%) underwent either MRI (n = 5) or CT (n = 19) after PET/CT, of which 17 patients were confirmed with cerebral metastases. The true positive rate was 70.8% (17/24), while the false positive rate of PET/CT was 29.2% (7/24). Nearly 94.1% (16/17) patients with confirmed cerebral metastases on MRI or CT had subsequent change in management. Among the remaining 16 patients with positive findings of cerebral metastases without further radiological correlation, 43.8% (7/16) patients had change in management after PET/CT. A total of 57.5% (23/40) patients had change in management after PET/CT. The point prevalence of detecting unknown cerebral metastases by PET/CT was 2.1% (40/1876). 94.1% patients with newly diagnosed brain metastases confirmed with either MRI or CT received immediate treatment for cerebral metastasis in this retrospective study. PET/CT demonstrated significant clinical impact by identifying cerebral lesions with mass effect and hence that timely treatment was offered.