Primary lymphoma of liver is a rare malignancy with non-specific clinical features and tumor markers. The presentation and imaging features may be indistinguishable from other hepatic malignant lesions. Pathological diagnosis is the gold standard, and early detection is essential to choose the treatment modality. Here, we share an interesting case of Primary Diffuse Large B cell lymphoma of liver and its imaging findings on Computed tomography (CT), Magnetic Resonance Imaging (MRI) and F-18 FDG PET/CT.

Carotid body paraganglioma is a slow growing tumor of head and neck region. It can rarely be malignant in nature which is characterized by distant metastases on anatomical imaging. We share an interesting presentation of a malignant carotid body on F-18 FDG PET/CT in form of liver and skeletal metastases.

Background/Objectives: Although the role of PET/CT imaging is well established in oncology, its diagnostic value in routine monitoring for recurrent colorectal cancer (CRC) is still controversial. The aim was to evaluate the diagnostic value of F-18 FDG PET/CT in detecting recurrent CRC in correlation with CEA, CA 19-9 levels, and conventional imaging modalities (CIM). Methods: Between 2009 and 2023, a retrospective study was performed including 134 CRC patients referred for PET/CT imaging on the suspicion of recurrence, based on elevated CEA and/or CA 19-9 and/or equivocal CIM findings. According to our institution\'s Tumor Board CRC protocol, after the initial treatment, which was dependent on the TNM stage (neoadjuvant therapy, primary resection, or adjuvant treatment), patients underwent a standard 5-year surveillance including CEA and CA 19-9 measurements, CIM, and colonoscopy, every six months. The statistics, including univariate and multivariate analyses were conducted using the IBM SPSS 20.0 statistical software. p-values < 0.05 were considered statistically significant. Results: Recurrent CRC was confirmed in 54/134 (40.3%) patients with elevated tumor markers. PET/CT showed high diagnostic performance in detecting recurrent CRC with sensitivity, specificity, PPV, NPV, and accuracy of 94.4%, 82.5%, 78.5%, 95.7%, and 87.3%, respectively. The CEA showed a high sensitivity of 98.1% but both low specificity and accuracy of 15% and 48.5%, respectively. The sensitivity, specificity, and accuracy for CA 19-9 and CIM for diagnosis of CRC recurrence were 44.4%, 67.5%, 58.2%, and 51.9%, 98.8%, 79.9%, respectively. The AUC for PET/CT, elevated CEA levels, CIM, and elevated CA 19-9 levels was 0.885 (95% CI: 0.824-0.946; p < 0.001), 0.844 (95% CI: 0.772-0.916; p < 0.001), 0.753 (95% CI: 0.612-0.844; p < 0.001), and 0.547 (95% CI: 0.442-0.652; p = 0.358), respectively. Univariate analysis showed that both PET/CT and CIM positive results were highly associated with CRC recurrence (p < 0.001 and p < 0.001, respectively). At the same time, gender, mucinous tumor type, presence of initial lymph node metastasis (N+), and presence of initial distant metastasis (M+) had no significance (p = 0.211, p = 0.158, p = 0.583, and p = 0.201, respectively). Our multivariate analysis showed that independent predictors for CRC recurrence are positive PET/CT scans (p < 0.001), positive CIM results (p = 0.001), and elevated CA 19-9 levels (p = 0.023). Although CA 19-9 was not detected as a statistically significant predictor in the univariate analysis (p = 0.358), in a multivariate analysis it was recognized as a significant predicting factor in detecting the CRC recurrence (p = 0.023). Conclusions: F-18 FDG PET/CT showed high diagnostic efficacy in CRC recurrence detection, in correlation with CEA levels, CA 19-9 levels, and CIM. This imaging modality should be routinely integrated into the post-operative follow-op in patients with elevated tumor markers.

BACKGROUND: This study aims to predict quantitative parameter in form of metabolic ratios to diagnose tumor thrombus on F-18 FDG PET/CT.
METHODS: This is a retrospective study from Nuclear Medicine department at All India Institute of Medical Sciences, Jodhpur, India. Patients with malignancies who underwent F-18 FDG PET/CT in our department or images sent for review from February 2020 till September 2022 were screened for tumor thrombus that comprised study group. Control group had patients with malignancy and no imaging evidence of tumor thrombus. Metabolic activities (SUVmax) of tumor thrombus, liver and descending aorta in study group, and that of IVC, liver and descending aorta in control group were recorded. Metabolic ratios of tumor thrombus to liver (SUR L) and to aorta (SUR A) in study group, and IVC to liver (SUR* L) and to aorta (SUR*A) in control group were compared using receiver operator curves.
RESULTS: Of 2277 studies screened, 12 had tumor thrombus. The most common primary malignant site and vessel involved were lung and IVC respectively. The median (IQR) SUR L, SUR A, SUR* L and SUR* A were 2.5 (3.25), 2.6  (6), 0.67 (0.18) and 1 (0.17) respectively. Area under ROC for SUR L and SUR A were 0.983 [95% CI: 0.955-1.0] and 0.958 [95% CI: 0.90-1.0] respectively. The ideal cut-off for SUR L was 0.953 (sensitivity 92.3%, specificity 98.0%) and for SUR A was 1.42 (sensitivity 84.6%, specificity 98.0%).
CONCLUSIONS: Metabolic ratios of tumor thrombus to liver (SUR L) and aorta (SUR A) have good diagnostic performance and can be useful in studies with non-iodinated contrast CT.

UNASSIGNED: Paget Disease (PD) is usually asymptomatic and discovered incidentally, it is known that it is exhibited low to high grade increased F-18 FDG uptake.
UNASSIGNED: In this study, we investigated the distinguishability of FDG PET/CT in incidental PD cases from other bone diseases and at different stages of the disease.
UNASSIGNED: In this cross-sectional, descriptive study, \"Paget\" identification associated with PET/CT reports was found in 69 of 18,119 studies (~3.8%). Of the 45 patients (33 males and 12 females) eligible for inclusion in the study, 35.6% had monostotic and 64.4% had polyostotic disease (p>0.5). There was no statistically significant difference in biochemical parameters between groups.
UNASSIGNED: According to the radiological appearance of the patients, 36 were in the mixed stage and 9 were in the blastic stage. Only the difference in ALP and creatinine values between the groups was statistically significant. SUVmax, SUVmean and HU values were found to be statistically significantly higher in pagetoid bones compared to control bone lesions. For SUVmax for PD bone lesion we found the 2.55 cutoff point with a sensitivity of 91% and a specificity of 84%.
UNASSIGNED: The specific radiological appearance of bone lesions and the evaluation of metabolic activity compared to normal bone seem to help differentiate PD from other lesions. Prospective studies are needed in the differentiation of FDG\'s disease stage and treatment response evaluation. The ability to differentiate between benign and malignant FDG avid bone lesions in oncological patients\' enables appropriate patient management, including avoiding unnecessary additional invasive procedures such as bone biopsy.

Gamma Delta (γδ) T-cell lymphomas are uncommon and aggressive neoplasms originating from the γδ receptor-bearing lymphocytes. The most frequent entities include primary hepatosplenic γδ T-cell lymphomas, primary cutaneous γδ lymphoma, and monomorphic epitheliotropic T-cell lymphoma. F-18 fluorodeoxyglucose (FDG) PET/CT is an important modality in the staging of Hodgkin\'s and various non-Hodgkin\'s lymphoma. However, literature is scare on imaging findings of γδ lymphoma on F-18 FDG PET/CT. In this review, we discuss briefly the clinical and biological features and present the spectrum of F-18 FDG PET/CT findings of γδ lymphoma.

Perfusion parameters obtained in F-18 FDG PET/CT performed for staging purposes in breast cancers may provide additional information about tumor biology as well as glucose metabolism. The aim of this study was to evaluate throughout F-18 FDG PET/CT the relationship between blood flow and glucose metabolism and histological parameters of the primary tumor, normal mammary gland, and axillary lymph nodes in breast cancer patients.
Sixty six female patients (mean age 51 y ± 12,81) were prospectively included to this study. We performed dynamic blood flow (f) study that started with 296-444 MBq (8-12 mCi) F-18 FDG injection and lasted for 10 minutes, and glucose metabolism (m) imaging one hour later. On each frame, mean activity concentration (AC) values (Bq/mL) were recorded on a spherical volume of interest (VOI) having a volume of ~ 1 cm3 on the hottest voxel of primary tumor (T), across normal breast gland (NG) and ipsilaterally axillary lymph nodes (iLN). Correlations among PET parameters and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (c-erbB2) and Ki67 index were analyzed.
T volume (TV) ranged from 1.1 to 85.28 cm3 [median (IR): 6.44 (11.78)]. There were positive correlations between c-erbB2 and TACf and between c-erbB2 and iLNACf (p = 0.045, r = + 0.248; p = 0.050, r = + 0.242). In the ER positive (ERP) patients, TV and TACm were significantly lower than those of ER negative (ERN) (respectively p = 0.044 and p = 0.041). In patients with two positive Ki-67 indices, iLN-SUVmax was significantly higher than one-positive patients (p = 0.020). There was a negative correlation between NGACm and histological grade of tumor (p = 0.005, r = - 0.365).
Breast cancer shows differences in progression, metastasis and survival due to its diversity in terms of molecular, biological and angiogenesis. High glucose metabolism in breast cancers is associated with tumor aggressiveness. Being able to examine tumor tissue characteristics such as blood flow and glucose metabolism with a single diagnostic technique and to reveal its relationship with histological parameters can provide a reliable pretherapeutic evaluation in breast cancers.

OBJECTIVE: This study aimed to evaluate the correlation between maximal standardized uptake value (SUVmax) of primary colon cancer and serum neutrophil-to-lymphocyte ratio (NLR), and to assess the prognostic value of SUVmax and serum NLR in stage I and II colon cancer patients.
METHODS: In this retrospective study a total of 128 patients with pathologically confirmed stage I and II colon cancer diagnosed between January 2014 and December 2017 were included. All patients underwent F-18 Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and differential white blood cell (WBC) counts before surgery. The correlations between SUVmax and NLR were assessed. The prognostic value of SUVmax and NLR for predicting recurrence-free survival (RFS) was investigated.
RESULTS: The mean NLR was 2.2 ± 1.2, and the mean SUVmax of primary tumor was 15.2 ± 7.9. There was significant correlation between NLR and SUVmax (rho=0.2, p=0.02). Mean follow-up period was 59.8 ± 19.2 months and 12 patients experienced a recurrence. In univariable analysis, NLR (p=0.0084, HR=5.0223, 95% CI=1.5117-16.6853), C-reactive protein (CRP) (p=0.021, HR=4.1115, 95% CI=1.2380-13.6551), carbohydrate antigen 19-9 (CA19-9) (p=0.0134, HR=4.2683, 95% CI=1.3519-13.4766), and Kirsten ras sarcoma viral oncogene (KRAS) mutation (p=0.0338, HR=3.4703, 95% CI=1.0998-10.9499) were significant prognostic factors for the recurrence. In multivariable analysis, NLR (p=0.0256, HR=4.1155, 95% CI=1.1887-14.2490) and CA19-9 (p=0.0257, HR=4.139, 95% CI=1.1880-14.4200) were independent prognostic factors for the recurrence.
CONCLUSIONS: Significant correlation was observed between SUVmax of primary colon cancer and serum NLR. Furthermore, in the multivariable analysis conducted on early colon cancer cases, NLR and CA19-9 were found to be independently associated with RFS. This suggested that NLR could be used as a supplementary tool for identifying patients at high risk of recurrence in early colon cancer. However, SUVmax was not associated with prognosis, suggesting that it cannot be used for predicting prognosis in early colon cancer.

Primary cutaneous Diffuse Large B-Cell Lymphoma-leg type (PCDLBCL-LT) is a rare subtype of cutaneous lymphomas, with high frequency of extra-cutaneous relapse and poor prognosis. We report a case of 70-year-old lady who was diagnosed with PCDLBCL-LT on biopsy and underwent a baseline F-18 FDG PET/CT, followed by interim and post-treatment PET/CTs. With this case report, we highlight the findings of F-18 FDG PET/CT in the staging of this cutaneous lymphoma, and also emphasize on its role in the response assessment.

Leptomeningeal carcinomatosis is a manifestation in which tumor cells migrate into meninges. Breast carcinoma presenting with leptomeningeal metastases is a rare phenomenon that can occur in an isolated form as well as with coexistent parenchymal brain metastases. The gold standard for diagnosis is cerebrospinal fluid analysis, while contrast-enhanced magnetic resonance imaging is the most commonly used imaging modality. Nuclear medicine imaging with flourine-18-fluorodeoxyglucose positron emission tomography/computed tomography has proved to be useful in detecting leptomeningeal metastases and, at times, even before anatomical changes occur. Here, we present a case of breast carcinoma presenting with both pachymeningeal and leptomeningeal metastases 10 years after treatment.