Liver Metastasis of Gastrointestinal Neuroendocrine Tumors: A Single Center Experience

Prospective data-driven respiratory gating of [68Ga]Ga-DOTATOC PET/CT

Aim

The aim of this prospective study was to evaluate a data-driven gating software’s performance, in terms of identifying the respiratory signal, comparing [⁶⁸Ga]Ga-DOTATOC and [¹⁸F]FDG examinations. In addition, for the [⁶⁸Ga]Ga-DOTATOC examinations, tracer uptake quantitation and liver lesion detectability were assessed.

Methods

Twenty-four patients with confirmed or suspected neuroendocrine tumours underwent whole-body [⁶⁸Ga]Ga-DOTATOC PET/CT examinations. Prospective DDG was applied on all bed positions and respiratory motion correction was triggered automatically when the detected respiratory signal exceeded a certain threshold (R value ≥ 15), at which point the scan time for that bed position was doubled. These bed positions were reconstructed with quiescent period gating (QPG), retaining 50% of the total coincidences. A respiratory signal evaluation regarding the software’s efficacy in detecting respiratory motion for [⁶⁸Ga]Ga-DOTATOC was conducted and compared to [¹⁸F]FDG data. Measurements of SUV_max, SUV_mean, and tumour volume were performed on [⁶⁸Ga]Ga-DOTATOC PET and compared between gated and non-gated images.

Results

The threshold of R ≥ 15 was exceeded and gating triggered on mean 2.1 bed positions per examination for [⁶⁸Ga]Ga-DOTATOC as compared to 1.4 for [¹⁸F]FDG. In total, 34 tumours were evaluated in a quantitative analysis. An increase of 25.3% and 28.1%, respectively, for SUV_max (P < 0.0001) and SUV_mean (P < 0.0001), and decrease of 21.1% in tumour volume (P < 0.0001) was found when DDG was applied.

Conclusions

High respiratory signal was exclusively detected in bed positions where respiratory motion was expected, indicating reliable performance of the DDG software on [⁶⁸Ga]Ga-DOTATOC PET/CT. DDG yielded significantly higher SUV_max and SUV_mean values and smaller tumour volumes, as compared to non-gated images.

Clinicopathological Spectrum of Primary and Metastatic Neuroendocrine Neoplasms

Introduction

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors with histological features varying from well-differentiated neuroendocrine tumors (WDNETs) to poorly differentiated neuroendocrine carcinomas (PDNECs). In this study, we investigated the clinicomorphological spectrum of NENs including tumor grade, site of origin, and metastasis.

Methods

We retrospectively studied 125 cases of NENs (at the Department of Histopathology, Liaquat National Hospital and Medical College, Karachi) between the years 2014 and 2020. Slides of these cases were retrieved from the departmental archives and were evaluated for the tumor type, grade, and site of origin.

Results

The mean age of the patients was 51.25±16.10 years. Overall, the liver was the most common site of the tumor (27.2%), followed by the small bowel (15.2%). Grade 2 was the most common tumor grade (40.8%), and most of the tumors were primary (68.8%). A total of 84.8% of the tumors were WDNETs/carcinoids, while 15.2% were PDNEC. The small bowel was the most common site of primary NENs, followed by the stomach and lung. Among primary neuroendocrine tumors, patients with PDNEC were significantly noted to have a higher mean age than WDNET/carcinoid. Similarly, PDNEC had a higher ki67 index than WDNET/carcinoid. For metastatic NENs, the liver was the most common site of metastasis (71.8%) with the GI/pancreatobiliary tract being the most common primary site of origin (51.3%). Tumors with primary lung origin were found to have a higher tumor grade than primary GI/pancreatobiliary tract origin NENs (p<0.0001).

Conclusion

In this study, we found that the small intestine and liver were the most common sites for primary and metastatic NENs, respectively. Moreover, primary PDNECs were associated with a higher mean age than WDNETs. Alternatively, metastatic NENs with primary lung origin had a higher tumor grade than primary GI/pancreatobiliary tract origin.

Analysis of B-ultrasound and contrast-enhanced ultrasound characteristics of different hepatic neuroendocrine neoplasm

BACKGROUND

Hepatic neuroendocrine neoplasm (hNEN) is a highly heterogeneous tumor. The exact identification of the source and malignant degree of hNEN is important. However, there is a lack of information regarding diagnosis of hNEN with imaging. In addition, no studies have compared the imaging between hNEN and hepatocellular carcinoma (HCC) and among different sources and malignant degrees of hNEN.

AIM

To compare the ultrasound characteristics between hNEN and HCC and among different sources and malignant degrees of hNEN.

METHODS

A total of 55 patients with hNEN were recruited and defined as the hNEN group. Among them, 35 cases of hNET were defined as the hNET group. Twenty cases of hepatic neuroendocrine carcinoma (hNEC) were defined as the hNEC group. Among the 55 lesions, 29 were transferred from the pancreas, 20 were from the gastrointestinal tract, and six were from other sites. In total, 55 patients with HCC were recruited and defined as the HCC group. The characteristic differences of B-mode ultrasound and contrast-enhanced ultrasound (CEUS) between hNEN and HCC and among different sources and malignant degrees of hNEN were compared.

RESULTS

In the hNEN group, the proportions of multiple liver lesions, unclear borders, and high echo lesions were higher than those in the HCC group. The proportions of non-uniform echo and peripheral acoustic halo were lower than those in the HCC group (P < 0.05). The washout to iso-enhancement time and washout to hypo-enhancement time were lower than those in the HCC group (P < 0.05). The characteristics of B-ultrasound and CEUS among different sources of hNEN were similar, and the differences were not statistically significant (P > 0.05). B-mode ultrasound characteristics of hNET and hNEC were similar. The proportions of low enhancement at portal venous phase, non-uniform enhancement forms, and combined tumor vasculature in the hNEC group were larger than those in the hNEN group (P < 0.05).

CONCLUSION

Compared with HCC, hNEN showed multiple intrahepatic lesions, uniform high echo, uniform high enhancement at arterial phase, and rapid washout. Low enhancement at portal venous phase, overall non-uniform enhancement form, and the proportion of combined tumor vasculature in hNEC were larger than those in hNET.

Gastroenteropancreatic neuroendocrine tumors: impact of consistent contrast agent selection on radiologists' confidence in hepatic lesion assessment on restaging MRIs

PURPOSE

To evaluate the impact of contrast agent selection on radiologists' confidence in assessing liver lesions on follow-up magnetic resonance imaging (MRI) studies in patients with neuroendocrine tumors.

METHODS

This Institutional Review Board-approved, retrospective study performed at a tertiary cancer center and a quaternary care urban academic hospital included all 694 follow-up abdominal MRI studies from 179 patients with gastroenteropancreatic neuroendocrine tumor performed from 01/01/2010 to 05/31/2015. Primary outcome measure was radiologists' confidence in assessing liver lesions on follow-up MRI. MRI reports were reviewed to abstract radiologists' confidence, classified as "equivocal" if any equivocal connotation (mention of limitation due to differences in contrast agent or follow-up recommendation with specific contrast agent) was present; or "unequivocal" if a precise, confident comparison to prior was documented without the use of ambiguous terms. A fellowship-trained radiologist separately evaluated 100 randomly selected reports and images to calculate interobserver agreement with the report classification (equivocal vs. unequivocal) and with the original MRI report, respectively. Chi-square test was used to compare the proportion of equivocal reports when "same" or "different" contrast agent was used for successive examinations.

RESULTS

Rates of equivocal reports were higher when different contrast agents were used for successive examinations compared to examinations with same contrast agent (13.2% [21/159] vs. 1.8% [10/535]; p < 0.0001). There was very good interobserver agreement for assessment of radiologist confidence (κ = 0.92 for report review, κ = 0.82 for image review).

CONCLUSIONS

Consistent use of contrast agent for follow-up MRIs allows more confident assessment of liver lesions in patients with neuroendocrine tumors.

Clinicopathological Characteristics of the primary and metastatic Hepatic Neuroendocrine Tumors and the relevant Prognosis-Related Factors: A Retrospective Study of 81 Cases in a Single Chinese Center

Aims: We aim to describe the clinicopathological characteristics of hepatic neuroendocrine tumors (HNETs) and evaluate the relevant prognosis-related factors. Methods: The clinical data of 81 consecutive patients with primary or metastatic HNETs from March 2000 to July 2014 were retrospectively analyzed. Results: The mean (SD) age was 59.68 (11.64) years, 69.15% were men. The percentages of Grade G1, G2 and G3 tumors were 4.94%, 25.93% and 69.13%, respectively. Thirty-five cases were primary HNETs. Primary HNETs were more common in patients with larger tumors, lymph nodes invasions, tumor necrosis and portal vein tumor thrombus. The 1-, 3-, and 5-year overall survival rate were 88.89%, 32.10%, and 8.64%, separately. The relapse rate was 81.48% (66/81) and the mean (SD) relapse time was 18.79 (10.99) months. Reduced survival rate was associated with lymph node metastases (P=0.034), tumor necrosis (P=0.048), hard texture of tumor character (P=0.001), multifocality of tumor numbers (P=0.043), and the immunohistochemical expression of NSE (P=0.000) and Syn (P=0.037). Patients with metastatic HNETs were demonstrated with a more decreased period of Progression-free Survival (PFS) and Overall survival (OS) than their primary HNETs counterparts (P<0.05). Conclusion: Primary HNETs cohort patients were more common with aggressive clinical presentation. The hard texture of tumor character, multifocality of tumor numbers, and the immunohistochemical expression of NSE and Syn were independent predictive factors. Patients who were pathologically diagnosed as the primary HNETs seemed to achieve a long-term survival.

Two Cases of Primary Hepatic Neuroendocrine Tumors and a Review of the Current Literature

Neuroendocrine tumors comprise approximately 1-2% of all gastrointestinal tumors, and while the liver is the most common site for metastasis of these tumors, primary hepatic neuroendocrine tumors are very rare entities. Since first being reported in 1958, there have been less than 150 cases reported in the literature. Because of the infrequent occurrence of these tumors, the pool of data available for analysis regarding these tumors is small. As such, the medical community must rely on the publication of case report data to further enlarge this data pool, with the hopes of eventually having enough data to draw meaningful, statistically significant conclusions with regard to diagnosis and management of these rare tumors. We have encountered two patients at our institution within the last year with primary hepatic neuroendocrine tumors. We present their cases in this manuscript in an effort to contribute to the available data on the disease. We also provide a concise review of the literature available to date regarding primary hepatic neuroendocrine tumors.

Neuroendocrine neoplasms of liver - A 5-year retrospective clinico-pathological study applying World Health Organization 2010 classification

AIM

To study the clinicopathological characteristics of neuroendocrine neoplasms (NEN) on liver samples and apply World Health Organization (WHO) 2010 grading of gastroenteropancreatic (GEP) NEN.

METHODS

Clinicopathological features of 79 cases of NEN of the liver diagnosed between January 2011 to December 2015 were analyzed. WHO 2010 classification of GEP NEN was applied and the tumors were graded as G1, G2 or G3. Two more categories, D1/2 (discordant 1/2) and D2/3 (discordant 2/3) were also applied. The D1/2 grade tumors had a mitotic count of G1 and Ki-67 index of G2. The D2/3 tumors had a mitotic count of G2 and Ki-67 index of G3. The follow up details which were available till the end of the study period (December 2015) were collected.

RESULTS

Of the 79 tumors, 16 each were G1 and G2, and 18 were G3 tumors. Of the remaining 29 tumors, 13 were assigned to D1/2 and 16 were D2/3 grade. Male preponderance was noted in all tumors except for G2 neoplasms, which showed a slight female predilection. The median age at presentation was 47 years (range 10-82 years). The most common presentation was abdominal pain (81%). Pancreas (49%) was the most common site of primary followed by gastrointestinal tract (24.4%) and lungs (18%). Radiologically, 87% of the patients had multiple liver lesions. Histopathologically, necrosis was seen in only D2/3 and G3 tumors. Microvascular invasion was seen in all grades. Metastasis occurred in all grades of primary NEN and the grades of the metastatic tumors and their corresponding primary tumors were similar in 67% of the cases. Of the 79 patients, 36 had at least one follow up visit with a median duration of follow up of 8.5 mo (range: 1-50 mo). This study did not show any impact of the grade of tumor on the short term clinical outcome of these patients.

CONCLUSION

Liver biopsy is an important tool for clinicopathological characterization and grading of NEN, especially when the primary is not identified. Eighty-seven percent of the patients had multifocal liver lesions irrespective of the WHO grade, indicating a higher stage of disease at presentation. Follow up duration was inadequate to derive any meaningful conclusion on long term outcome in our study patients.