Incidentally Detected Gallbladder Carcinoma: Can F-18 FDG PET/CT Aid in Staging and Prognostication?

Purpose: Incidental gallbladder carcinoma (IGBC) is diagnosed in post-cholecystectomy specimens for benign indications, where the role of 2-fluro-2-deoxyglucose positron emission tomography/computed tomography(FDG-PET/CT) is not clearly defined. The present study aimed to assess the benefits of staging and prognosticating with FDG-PET/CT in IGBC. Materials and Methods: A retrospective observational study from a tertiary-care center from January 2010 to July 2020 was performed. The demographic, clinical, histopathological, and treatment-related histories were collected. FDG-PET/CT-image findings were compared with survival outcomes through telephonic follow-up. The chi-square test was used for comparing frequencies. The univariate and multivariate survival estimates were analyzed using the Kaplan-Meier analysis and the Cox-proportional hazard model, respectively. Log-rank test was used to compare the Kaplan-Meier curves. Results: The study included 280 postcholecystectomy participants (mean age: 52 ± 11 years; women: 227) of whom 52.1% had open surgery(146/280). Residual disease in the gallbladder fossa (54.8% vs. 36.6%, p = 0.002) and liver infiltration (32.9% vs. 22.4%, p = 0.05) were seen more frequently in open surgery compared to laparoscopic surgery, while anterior abdominal wall deposits were more common in laparoscopy(35.1% vs. 24%,p = 0.041). FDG-PET/CT changed the management in 10% (n = 28) of patients compared to contrast-enhanced CT. The median survival was 14 months (95%CI-10.3-17.7). A higher stage of the disease on the FDG-PET/CT (loco-regional disease-HR 4.86, p = 0.006; metastatic disease-HR 7.53, p < 0.001) and the presence of liver infiltration (HR-1.92, p = 0.003) were independent predictors of poor survival outcomes. Conclusion: FDG-PET/CT detects residual and metastatic disease in patients with IGBC, enabling the institution of appropriate management and acting as a tool for prognostication of survival.

Prostate-Specific Membrane Antigen-Avid Neurofibroma Mimicking Cutaneous Metastasis in Metastatic Castration-Resistant Prostate Cancer on 18 F-PSMA-1007 PET/CT.

ABSTRACT: The occurrence of cutaneous metastases in prostate cancer is exceedingly rare. Many benign lesions and nonprostatic cancers can express the prostate-specific membrane antigen (PSMA). They can potentially mimic metastasis of prostate cancer and lead to misinterpretation of PSMA PET/CT findings. Additionally, it has significant management and prognostic implications. We present a rare case of an 88-year-old man with metastatic castration-resistant prostate cancer who showed a PSMA-expressing subcutaneous nodule in the scalp on 18 F-PSMA-1007 PET/CT, raising the suspicion of cutaneous metastasis. However, its biopsy revealed a neurofibroma, altering the disease prognosis and management.

177 Lu-DOTATATE Salvage Therapy in Rapidly Progressing Neuroendocrine Tumor With Poor Performance Status.

ABSTRACT: Peptide receptor radionuclide therapy (PRRT) has shown to be effective and safe in metastatic gastroenteropancreatic and nongastroenteropancreatic neuroendocrine tumors. However, the selection criteria for PRRT are restricted to patients with good performance status (Eastern Cooperative Oncology Group score ≤2 or Karnofsky performance score ≥60). This denies many patients with adequate somatostatin receptor expression and biochemical profiles from the beneficial effects of PRRT on the quality of life, daily function, and overall survival. The 2 cases highlight the favorable response of PRRT in patients with metastatic neuroendocrine tumor having a very poor performance status initially.

Neoadjuvant Peptide Receptor Radionuclide Therapy in a Rare Case of Pediatric Primary Hepatic Gastrinoma.

ABSTRACT: Gastrinomas with predilection for the adult male population are located in the gastrinoma triangle (>90%). Primary hepatic gastrinoma especially in pediatric population is very rare. Peptide receptor radionuclide therapy has shown benefit in metastatic gastroenteropancreatic neuroendocrine tumors (NETs) with an increasing interest in expanding its role as neoadjuvant treatment modality to improve the surgical candidature in inoperable NETs. There is currently no literature supporting its role in the pediatric NET patients. We present a rare case of a young boy with primary hepatic gastrinoma where 177Lu-based peptide receptor radionuclide therapy in the neoadjuvant setting contributed to his final disease-free status.

Unusual Sites of Visceral Spread in Prostate Cancer: A Prostate-Specific Membrane Antigen-Based Theranostic Imaging Series.

ABSTRACT: Prostate cancer commonly metastasizes to lymphatic and skeletal systems with lesser frequency to visceral organs; however, uncommon visceral sites have also been found and reported as case reports. We present a series of uncommon metastatic visceral spread in prostate cancer on prostate-specific membrane antigen-based diagnostic and posttherapeutic imaging modalities.

Role of non-contrast CT component of prostate-specific membrane antigen PET/CT scan in the detection of peripheral zone prostate cancer.

OBJECTIVE: The aim of this study was to look for feasibility of non-contrast CT (NCCT) in detecting peripheral zone prostate cancer (PCa). METHODS: A retrospective analysis included 50 biopsy-proven PCa patients between April 2019 and March 2022 who underwent staging whole body prostate-specific membrane antigen (PSMA)/CT prior to treatment. The control subjects were 50 randomly selected adult male patients who underwent PET/CT for non-prostate malignancy during the same time period. Two readers independently calculated the Hounsfield unit (HU) of normal peripheral zone, central zone, and corresponding PSMA avid focus in cases. RESULTS: No significant difference was seen in the mean HU value of normal peripheral zone between cases and controls. Significant difference in the mean HU was seen between the PSMA avid focus in cases (40.1 ± 6.2) and normal peripheral zone of cases (28.2 ± 7.0) and controls (27.7 ± 5.8). No significant difference was found between the mean HU values of high-grade PCa and non-high-grade PCa. Receiver operating characteristic (ROC) curve analysis revealed a mean HU cut-off of ≥35 for detecting PCa with a sensitivity and specificity of 86% and 90%, respectively, between cases and controls (AUC 0.88). CONCLUSION: Detection of clinically significant PCa is possible on routinely performed NCCT scans. Radiologists should routinely look for and convey these findings to facilitate further work-up and early detection of PCa. ADVANCES IN KNOWLEDGE: Our study adds to the knowledge that NCCT scans performed for unrelated indications can serve as a screening tool for clinically significant PCa.

68 Ga-Pentixafor PET/CT for in-vivo mapping of CXCR4 receptors as potential radiotheranostic targets in soft tissue and bone sarcoma: preliminary results.

OBJECTIVE: To evaluate the diagnostic utility of 68 Ga-Pentixafor PET/CT for in vivo imaging of CXCR4 receptors in soft tissue/bone sarcoma. METHODS: Ten (7M: 3F; mean age = 24.7 ± 14.2 years) consecutive patients with clinical and radiological evidence of bone/soft tissue sarcoma were recruited prospectively whole body 68 Ga-Pentixafor PET/CT imaging was performed at 60-min after tracer administration. After performing standard CT, PET acquisition from head to toe was done (3 min/bed position) in a caudocranial direction. PET/CT data was reconstructed and SUV max , SUV mean values, target-to-background ratio (TBR) and active tumor volume (cc) were computed for the tracer avid lesions. Histopathological and IHC analysis was performed on the surgically excised primary tumors. CXCR4 receptors' intensity was evaluated by visual scoring. RESULTS: The mean SUV max and SUV mean values in the primary tumors were 4.80 ±â€…1.0 (3.9-7.7) and 2.40 ±â€…0.60 (0.9-4.0). The mean TBR and tumor volume (cc) were 1.84 ±â€…1.3 and 312.2 ±â€…285. Diagnosis of osteosarcoma in 7, chondrosarcoma, leiomyosarcoma and synovial sarcoma in 1 patient each was confirmed on HP analysis. Distant metastatic lesions were seen in 3/10 patients. Nuclear CXCR4 receptors' positivity was seen in 5, cytoplasmic in 4 and both pattern seen in 1 patient. The mean CXCR4 receptors' intensity was found to be 7.6 ±â€…2. The highest SUV max value of 7.7 was observed in the patient having both cytoplasmic and nuclear CXCR4 expression. SUV max was found to be poorly correlated ( r  = 0.441) with CXCR4 expression. CONCLUSION: 68 Ga-Pentixafor PET/CT detects CXCR4 receptors over-expressed in sarcoma, its radio-theranostics potential needs detailed evaluation.

Potential role of 68Ga-PSMA PET/CT in metastatic renal cell cancer: A prospective study.

PURPOSE: Prostate-specific membrane antigen (PSMA), in addition to its utility in prostate cancer, is also an angiogenic imaging marker for hypervascular tumors like renal cell carcinoma (RCC). Our study aims to assess the potential role of 68Ga-PSMA-11 positron emission tomography (PET)/CT in metastatic RCC and compare it with contrast-enhanced computed tomography (CECT). METHODS: Biopsy-proven RCC patients with known or suspected distant metastases who underwent 68Ga-PSMA-11 PET/CT for staging/restaging were prospectively recruited. Those patients who had undergone 18F-FDG PET/CT within six weeks of 68Ga-PSMA PET/CT were also included retrospectively for comparative analysis. A patient-based and lesion-based analysis was done to compare the lesion detection rates of CECT, 68Ga-PSMA-11 PET and 18F-FDG PET. PET-based quantitative parameters were also compared between both the PET modalities. Impact of baseline parameters on survival was assessed using Cox regression analysis. A p-value of < 0.05 was considered significant. RESULTS: Thirty-seven patients with median age 60 years ± 13 years (range = 26-76 years) were included in the study. Twenty-seven patients had clear cell (cc) RCC, six had papillary RCC (pRCC), and one each had an eosinophilic variant of ccRCC, collecting duct RCC, translocation RCC and poorly differentiated RCC. 68Ga-PSMA-11 PET performed better in detecting marrow and equivocal bone lesions and worse in detecting liver lesions compared to CECT. 68Ga-PSMA-11 PET-based angiogenic tumor burden estimation using Total Lesion-PSMA (TL-PSMA) and PSMA-Total volume (PSMA-TV) had a prognostic impact on the survival of patients. 68Ga-PSMA-11 PET also detected more lesions and showed significantly higher SUVmax than 18F-FDG PET. CONCLUSION: 68Ga-PSMA-11 PET/CT performs better than CECT and 18F-FDG PET/CT in metastatic evaluation and has prognostic value in the management of clear cell RCC.

Estimation of absorbed dose to salivary glands in mCRPC patients undergoing 177 Lu- PSMA-617 radioligand therapy using quantitative SPECT-CT at single time point: a single-center feasibility study.

OBJECTIVE: 177 Lu-PSMA-617-radioligand therapy (RLT) has shown promising therapeutic role in patients with metastatic castration-resistant prostate cancer. However, off-target action in salivary glands often presents with xerostomia. Personalized dosimetry can help in optimizing the treatment, however, has so far been tedious due to multiple time-point imaging. In this prospective study, we intended to estimate the absorbed dose delivered to the salivary glands in patients undergoing 177 Lu-PSMA-617-RLT using quantitative SPECT/CT at a single time point. METHODS: Patients undergoing 177 Lu-PSMA-617 RLT were included in this prospective study. Post-therapy whole-body images and regional quantitative single time-point SPECT/CT were acquired at 24 h with high-energy collimator. The data was processed and analyzed using Q.Metrix software. A scaling factor, that is, the time-integrated activity conversion factor was applied for the image acquired at 24 h. Absorbed doses were computed using MIRD scheme and OLINDA software. RESULTS: A total of 21 patients (mean age: 66 ±â€…9 years) were included. The value of mean absorbed dose for the parotid glands was 1.90 ±â€…1.31Gy (range: 0.26-6.23) and that for the submandibular glands was 1.37 ±â€…0.94Gy (range: 0.16-3.65). The mean absorbed doses per administered activity for the parotid and submandibular glands were 0.26 ±â€…0.18 Gy/GBq and 0.19 ±â€…0.12 Gy/GBq, respectively. The absorbed doses were estimated for one cycle of therapy and were well within acceptable limits. None of the patients experienced dryness of mouth. CONCLUSION: Single time-point dosimetry with quantitative SPECT/CT is feasible and can be standardized to estimate the absorbed dose to salivary glands instead of multiple time-point acquisitions.

Sunitinib in Tandem With 177 Lu-DOTATATE Therapy in Advanced Pancreatic Neuroendocrine Tumor : A New Treatment Approach.

ABSTRACT: Various systemic treatment options are available for advanced pancreatic neuroendocrine tumors (NETs); however, individual treatment may be suboptimally effective. Sunitinib inhibits multiple kinases and signaling pathways with delay in tumor growth, whereas peptide radioreceptor therapy (PRRT) delivers targeted radiation to the tumors in pancreatic NETs. There is a dearth of literature on the combined or tandem use of these systemic treatment modalities. We present a case of 40-year-old man with advanced pancreatic NET where PRRT or sunitinib as monotherapy had a suboptimal treatment response, but the use of sunitinib in tandem with 177 Lu-PRRT reinforced the response to the treatment.

Excellent Response to Full-Dose 177 Lu-PSMA-617 RLT in Metastatic Castration-Resistant Prostate Cancer With Transplant Kidney : A Step Ahead.

ABSTRACT: 177 Lu-PSMA radioligand therapy (RLT) has shown very encouraging results in metastatic castrate-resistant prostate cancer (mCRPC) patients with acceptable adverse events. The adverse events of RLT are mainly limited to salivary glands and kidneys. However, there is dearth of available data of RLT in transplanted kidney patients with mCRPC. Here is a case of 68-year-old mCRPC patient with history of renal transplant who underwent 4 cycles of 177 Lu-PSMA-617 RLT (~7.4 GBq/cycle). Posttherapy serum creatinine and glomerular filtration rate remained stable along with excellent response and symptomatic improvement, thus demonstrating the safety of full dose of 177 Lu-PSMA in renal transplant patients.

Hot Embolus Artifact Mimicking Disease Progression in Post-therapy 177Lu-DOTATATE Scan: Incremental Value of SPECT/CT.

Peptide receptor radionuclide therapy (PRRT) has become an established treatment for patients with inoperable and/or metastatic, well-differentiated neuroendocrine tumors with overexpression of somatostatin receptor type 2 (SSTR-2). The post-therapy 177Lu-DOTATATE whole-body scan not only assesses the biodistribution of the lesions seen on pre-therapy 68 Ga-SSTR PET/CT scan but also provides a quick assessment of disease status and dosimetry during treatment. Like any other radionuclide scan, the whole-body 177Lu-DOTATATE scan may also show abnormal radiotracer uptake, which may require further imaging to establish its exact etiology. Though radiotracer emboli mimicking focal pulmonary lesions have been described with 18F-FDG and 68 Ga-DOTANOC PET/CT scans, similar artifacts with post-therapy 177Lu-DOTATATE scans have not been described. Herein, we report two cases of hot emboli in the post-therapy 177Lu-DOTATATE scans.

Increased PSMA Expression in 177 Lu-PSMA-617 Scan in Metastatic Castrate-Resistant Prostate Cancer Patient Treated With PSMA Radioligand Therapy and Enzalutamide : A Potential Game-Changer.

ABSTRACT: Androgen deprivation therapy plays an integral role in the treatment algorithm of advanced prostate cancer. Enzalutamide has shown great benefit in castrate-sensitive as well as resistant prostate cancer. Few studies have shown that enzalutamide can potentially increase the PSMA expression on 68 Ga-PSMA-11 PET/CT imaging in patients with metastatic castrate-resistant prostate cancer. We present an interesting case where addition of short course of enzalutamide resulted in increased localization of 177 Lu-PSMA-617 in metastatic lesions on posttherapy scan pointing to the added benefit of PSMA RLT.

False positive finding on whole-body iodine-131 scan secondary to contaminated face mask: an uncommon peril in current COVID pandemic.

Covid-19 has changed the practice of present-day medicine. Social-distancing, hand-sanitation and use of face-mask are important measures taken against its spread. Post-thyroidectomy whole-body diagnostic I-131 scan is an important preliminary investigation for risk stratification and further management in thyroid cancer. False positive findings on diagnostic scan are not uncommon and must be evaluated to avoid unnecessary work-up and treatment. Clinical and biochemical correlation with adjunct SPCET/CT imaging may differentiate true from false-positive lesions. We report a case of unusual false positive linear neck tracer on whole-body diagnostic I-131 scan due to the use of an I-131 contaminated face mask.

Genomic characterization of metastatic castration-resistant prostate cancer patients undergoing PSMA radioligand therapy: A single-center experience.

BACKGROUND: Genomic defects in DNA-damage repair (DDR) mechanisms have been proposed to affect the radiosensitivity of prostate cancers. In this study, we intended to evaluate the prevalence of genetic alterations in a cohort of metastatic castration-resistant prostate cancer (mCRPC) patients undergoing radioligand therapy (RLT) with prostate-specific membrane antigen (PSMA)-inhibitors as well as the impact of such mutations on treatment outcomes. METHODS: Data of consecutive mCRPC patients from 2017 to 2021 who were treated with PSMA-RLT and underwent next-generation sequencing (NGS) were collected and analyzed for response and survival outcomes. RESULTS: In 95 patients of mCRPC treated with PSMA-RLT, 15 patients (median age: 66 years, range: 50-73 years; [177 Lu]Lu-PSMA-617, n = 12; [225 Ac]Ac-PSMA-617, n = 3) underwent NGS. The median progression-free survival (PFS) of this cohort was 3 months (95% confidence interval: 1.6-4.4 months). On NGS, 21 genetic alterations were reported in 10/15 (67%) patients, of which 13 were DDR-associated alterations involving the genes: ATM (n = 3), BRCA2 (n = 3), TP53 (n = 2), PTEN (n = 2), FANCD2 (n = 1), FANCM (n = 1), and NBN (n = 1). Overall, 5/15 (33%) patients harbored six pathogenic variants (BRCA2, n = 2; ATM, n = 1; TP53, n = 1; PTEN, n = 2). No significant difference was noted for the biochemical response, radiological response, PFS, and overall survival between the patients with and without genetic alterations. CONCLUSIONS: Patients of mCRPC undergoing PSMA-RLT were frequently seen to harbor DDR-associated aberrations, albeit with no significant impact on treatment outcomes. Large prospective trials comparing PSMA-RLT-related outcomes in DDR-deficient and -proficient patients are required to bring out the differences, if any, in a more observable manner.

Radioactive Iodine Uptake in Postoperative Seroma: A Cause for False Positivity.

Besides the known physiologic uptake of 131I, the literature describes various false-positive findings on 131I scans in benign lesions, inflammation, traumatic sites, and postsurgical sites, to name a few. However, to the best of our knowledge, no study has shown false-positive uptake of 131I in a postoperative seroma at the postsurgical site. We describe such a case here.

68Ga-DOTANOC PET/CT in Adrenal Schwannoma.

ABSTRACT: Adrenal schwannoma is a rare adrenal incidentaloma. It is a benign tumor arising from the Schwann cells. Differentiating benign from malignant adrenal lesions requires a combination of clinical, biochemical, imaging, and histopathological findings. 68Ga-DOTANOC PET/CT is one of the sensitive imaging modalities to detect adrenal lesions such as pheochromocytoma. Multiple benign and malignant lesions show somatostatin receptor expression causing a high probability of false-positive findings on somatostatin receptor imaging. We present a case of adrenal incidentaloma positive on 68Ga-DOTANOC PET, which revealed a benign adrenal spindle cell tumor on histopathology.

Bilaterally ectopic pelvic kidneys masquerading as horseshoe kidney in Fanconi anemia.

Fanconi anemia (FA) is a genetic disease associated with the risk of different congenital malformations, bone marrow failure, and predisposition to cancer. Congenital abnormalities of the kidney and urinary tract are not infrequent in FA with renal ectopia being one of them. The incidence of the bilateral pelvic ectopic kidney is restricted to only a few reported cases; however, its association with FA has never been reported in the literature. We present a case of Fanconi anemia in a young girl with apparently fused kidneys on a 99mTc-DMSA planar scan which was confirmed to be bilateral pelvic kidneys on hybrid cross-sectional imaging.

Pancreatic hemorrhage contributes to late mortality in patients with acute necrotizing pancreatitis.

OBJECTIVES: The frequency, risk factors, and impact on survival of hemorrhage into (peri)pancreatic collections in patients with acute pancreatitis (AP) has not been well studied. The study was designed to evaluate the risk factors for hemorrhage, successful hemostasis and its effect on in-hospital mortality. METHODS: In a prospective cohort study for prediction of severity of AP, the incidence, risk factors, and outcomes of pancreatic hemorrhage were analyzed. Patients with significant hemorrhage were managed according to a predefined protocol including endovascular intervention. RESULTS: Out of 363 patients hospitalized during the study-period, 33(9%) patients developed hemorrhage. Median time from onset of AP to hemorrhage was 59(45-68) days. The cause of hemorrhage was arterial in 19(57.5%) patients and unlocalized in 14(42.5%) patients. Hemorrhage was managed by conservative approach in 7 (21.2%), radiographic angioembolisation in 16 (48.5%), radiographic angioembolisation followed by surgery in 3 (9.1%), and surgery in 7 (21.2%) patients. Persistent organ failure [aHR 2.3 (1.1-5.1), p = 0.03], use of large bore (>20 Fr) catheter for initial drainage [aHR 3.9 (1.7-9.1), p = 0.001] and extensive (>50%) necrosis [aHR 3.1 (1.4-6.9), p = 0.005] were significant risk factors for hemorrhage. Hemorrhage was an independent predictor of mortality [aHR 2.0 (1.2-3.4), p = 0.008] in addition to persistent organ failure (aHR 12.1 (5.7-25.8), p < 0.001). In-hospital mortality in patients with hemorrhage was 22/33 (66.7%) vs. 81/330 (25%) in no hemorrhage group [p <0.001]. CONCLUSION: Pancreatic hemorrhage occurs later in the course of acute pancreatitis in relatively sicker group of patients with organ failure and extensive necrosis, and is independently associated with a higher risk of in-hospital mortality.

Versatile Role of 18F-FDG PET/CT in a Patient with Pan-cerebellar Paraneoplastic Manifestation Due to Underlying Hodgkin's Lymphoma.

Hodgkin's lymphoma most commonly presents as painless lymphadenopathy and systemic B symptoms like fever, night sweats, and weight loss. But rarely, it can present with unusual paraneoplastic manifestations. In the present case, we report a 30-year-old woman who presented with sub-acute onset pan-cerebellar symptoms. The serum neuronal antibody panel was negative. She underwent F-18 FDG PET/CT to evaluate the neoplastic etiology as the underlying cause, which demonstrated both the primary etiology and the paraneoplastic changes in the brain.