CT and enhanced CT in diagnosis of gastrointestinal neuroendocrine carcinomas

China special issue on gastrointestinal tumors-Radiological features of pathological complete response in mismatch repair deficient colorectal cancer after neoadjuvant PD-1 blockade: A post hoc analysis of the PICC phase II trial

Neoadjuvant programmed cell death protein 1 (PD-1) blockade exhibits promising efficacy in patients with mismatch repair deficient (dMMR) colorectal cancer (CRC). However, discrepancies between radiological and histological findings have been reported in the PICC phase II trial (NCT03926338). Therefore, we strived to discern radiological features associated with pathological complete response (pCR) based on computed tomography (CT) images. Data were obtained from the PICC trial that included 36 tumors from 34 locally advanced dMMR CRC patients, who received neoadjuvant PD-1 blockade for 3 months. Among the 36 tumors, 28 (77.8%) tumors achieved pCR. There were no statistically significant differences in tumor longitudinal diameter, the percentage change in tumor longitudinal diameter from baseline, primary tumor sidedness, clinical stage, extramural venous invasion status, intratumoral calcification, peritumoral fat infiltration, intestinal fistula and tumor necrosis between the pCR and non-pCR tumors. Otherwise, tumors with pCR had smaller posttreatment tumor maximum thickness (median: 10 mm vs 13 mm, P = .004) and higher percentage decrease in tumor maximum thickness from baseline (52.9% vs 21.6%, P = .005) compared to non-pCR tumors. Additionally, a higher proportion of the absence of vascular sign (P = .003, odds ratio [OR] = 25.870 [95% CI, 1.357-493.110]), nodular sign (P < .001, OR = 189.000 [95% CI, 10.464-3413.803]) and extramural enhancement sign (P = .003, OR = 21.667 [2.848-164.830]) was observed in tumors with pCR. In conclusion, these CT-defined radiological features may have the potential to serve as valuable tools for clinicians in identifying patients who have achieved pCR after neoadjuvant PD-1 blockade, particularly in individuals who are willing to adopt a watch-and-wait strategy.

Efficacy of multi-slice spiral computed tomography in evaluating gastric cancer recurrence after endoscopic submucosal dissection

BACKGROUND

Recurrence is the major challenge facing endoscopic submucosal dissection (ESD)-based treatment therapies for early gastric cancer (EGC). Urgent development of simple and easy surveillance approaches will enhance clinical treatment of the disease.

AIM

To explore the role of computed tomography (CT) recurrence in evaluating EGC after ESD treatment.

METHODS

We retrospectively recruited patients from our endoscopy department, between January 2002 and December 2015, and analyzed their basic characteristics, including symptoms, CT results, and results of endoscopy with biopsy, among others.

RESULTS

Among a total of 2150 patients EGC patients surveyed, 1362 met our inclusion and exclusion criteria and were therefore enrolled in our study. The cohort's sensitivity of CT for recurrent GC and specificity were 44.22% and 43.86%, respectively, with negative and positive predictive values of 40.15% (275/685) and 48.01% (325/677), respectively. The area under the curve of arterial and venous CT values for recurrent EGC were 0.545, and 0.604, respectively. Receiver operating characteristic curve revealed no statistically significant differences between arterial and venous CT values for recurrent EGC.

CONCLUSION

Enhanced CT has superior diagnostic efficacy, but less accuracy, compared to gold standard techniques in patients with recurrent EGC.

Unsuspected gastric glomus tumour

Gastric glomus tumours (GGTs) are rare predominantly benign, mesenchymal neoplasms that commonly arise from the muscularis or submucosa of the gastric antrum and account for <1% of gastrointestinal soft-tissue tumours. Historically, GGT has been difficult to diagnose preoperatively due to the lack of unique clinical, endoscopic and CT features. We present a case of an incidentally identified GGT in an asymptomatic man that was initially considered a neuroendocrine tumour (NET) by preoperative fine-needle aspiration biopsy with focal synaptophysin reactivity. An elective robotic distal gastrectomy and regional lymphadenectomy were performed. Postoperative review by pathology confirmed the diagnosis of GGT. GGTs should be considered by morphology as a differential diagnosis of gastric NET on cytology biopsy, especially if there is focal synaptophysin reactivity. Additional staining for SMA and BRAF, if atypical/malignant, can help with this distinction. Providers should be aware of the biological behaviour and treatment of GGTs.

Development and validation of a contrast-enhanced CT-based radiomics nomogram for preoperative diagnosis in neuroendocrine carcinoma of digestive system

Objectives

To develop and validate a contrast-enhanced CT-based radiomics nomogram for the diagnosis of neuroendocrine carcinoma of the digestive system.

Methods

The clinical data and contrast-enhanced CT images of 60 patients with pathologically confirmed neuroendocrine carcinoma of the digestive system and 60 patients with non-neuroendocrine carcinoma of the digestive system were retrospectively collected from August 2015 to December 2021 at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, and randomly divided into a training cohort (n=84) and a validation cohort (n=36). Clinical characteristics were analyzed by logistic regression and a clinical diagnosis model was developed. Radiomics signature were established by extracting radiomic features from contrast-enhanced CT images. Based on the radiomic signature and clinical characteristics, radiomic nomogram was developed. ROC curves and Delong's test were used to evaluate the diagnostic efficacy of the three models, calibration curves and application decision curves were used to analyze the accuracy and clinical application value of nomogram.

Results

Logistic regression results showed that TNM stage (stage IV) (OR 6.8, 95% CI 1.320-43.164, p=0. 028) was an independent factor affecting the diagnosis for NECs of the digestive system, and a clinical model was constructed based on TNM stage (stage IV). The AUCs of the clinical model, radiomics signature, and radiomics nomogram for the diagnosis of NECs of the digestive system in the training, validation cohorts and pooled patients were 0.643, 0.893, 0.913; 0.722, 0.867, 0.932 and 0.667, 0.887, 0.917 respectively. The AUCs of radiomics signature and radiomics nomogram were higher than clinical model, with statistically significant difference (Z=4.46, 6.85, both p < 0.001); the AUC difference between radiomics signature and radiomics nomogram was not statistically significant (Z=1.63, p = 0.104). The results of the calibration curve showed favorable agreement between the predicted values of the nomogram and the pathological results, and the decision curve analysis indicated that the nomogram had favorable application in clinical practice.

Conclusions

The nomogram constructed based on contrast-enhanced CT radiomics and clinical characteristics was able to effectively diagnose neuroendocrine carcinoma of the digestive system.

Colonic actinomycosis presenting as a palpable colonic mass with normal colonic mucosa

Colonic actinomycosis is rare and can present as an ill-defined intra-abdominal mass that can be difficult to differentiate from colon cancer. This case report aims to share the details of this case and provide diagnostic clues. A 63-year-old female presented with a palpable right-sided abdominal mass. Computed tomography (CT) revealed irregular thickening of the colonic hepatic flexure, and colonoscopy detected no abnormalities. Five months later, the patient returned with an increase in the mass size. Repeat CT revealed lesion expansion, with suspected abdominal wall invasion. Extended right-hemicolectomy with abdominal wall wedge resection was performed, and the histological results were compatible with actinomycosis infection. Colonic actinomycosis is a rare chronic inflammatory disease. Normal colonic mucosa during colonoscopy, with clinical and imaging findings, may help physicians diagnose the condition preoperatively.

Radiomics analysis of CT imaging for differentiating gastric neuroendocrine carcinomas from gastric adenocarcinomas

PURPOSE

To develop and evaluate a CT-based radiomics nomogram for differentiating gastric neuroendocrine carcinomas (NECs) from gastric adenocarcinomas (ADCs).

METHODS

CT images of 63 patients with gastric NECs were collected retrospectively, and 63 patients with gastric ADCs were selected as the control group. Univariate analysis was used to identify the significant factors of clinical characteristics and CT findings for differentiating gastric NECs from ADCs. Radiomics analysis was applied to CT images of unenhanced, arterial phase and venous phase, respectively. A radiomics nomogram incorporating the radiomics signature and the subjective CT findings was developed and its diagnostic ability was evaluated. The diagnostic performances of CT findings model, radiomics signature and radiomics nomogram were compared using DeLong test.

RESULTS

The tumor margin and lymph node (LN) metastasis were independent predictors for differentiating gastric NECs from ADCs. The radiomics signature based on venous phase presented superior AUC of 0.798 [95 % confidence interval (CI), 0.657-0.938] in validation cohort. The nomogram incorporated the radiomics signature, tumor margin and LN metastasis showed AUCs of 0.821 (95 %CI: 0.725-0.895) in the primary cohort and 0.809 (95 %CI: 0.649-0.918) in the validation cohort. Moreover, the radiomics nomogram showed good discrimination and calibration. The diagnostic performance of CT findings model was significantly lower than that of radiomics nomogram (p =  0.001) and radiomics signature (p = 0.025).

CONCLUSIONS

Radiomics analysis exhibited good performance in differentiating gastric NECs from ADCs, and the radiomics nomogram may have significant clinical implications on preoperative detection of gastric malignant tumors.

Neuroendocrine carcinoma of the stomach: clinical features and CT findings

PURPOSE

The purpose of the study is to investigate the computed tomographic characteristic and clinical findings of gastric neuroendocrine carcinoma (G-NEC) to increase awareness of this disease.

METHODS

Twenty-two patients with a diagnosis of G-NEC were identified through the PACS of our hospital from August 2010 to November 2014. The clinical data, computed tomography (CT) features, and pathology records were analyzed.

RESULTS

Among the 22 patients, 21 were male (95.45%), and 1 was female (4.55%). The mean age was 63.5 years old. Positive rates of neuroendocrine markers were 77.28% for chromogranin A staining, 86.36% for synaptophysin staining. All cases were single lesions including 16 (72.73%) in the gastric fundus, 3 (13.64%) in the gastric body and 1 (4.55%) in the gastric angle. Additionally 2 (9.09%) were found in the gastric antrum. Gastric wall was local thickening in 15 cases, and mass formation in 7 cases, with the stenosis and deformation of the adjacent gastric cavity. The long-axis diameter of the lesions ranged from 1.2 to7.4 cm (mean diameter, 2.47 cm), and the long-axis diameter was <2 cm in 12 case, 2-7.4 cm in 10 cases. The radiodensity values of the lesions were homogeneous density in 15 cases ranging from 22 to 47 HU (mean 34 HU). An ulcer with an irregular base and slightly raised borders located in the stomach was seen in 19 cases. The CT images showed homogeneous enhancement in 15 cases and heterogeneous enhancement in 7 cases. Obvious enhancement was seen in two cases, moderate enhancement was seen in sixteen cases, and mildly enhancement was seen in four cases. The peak value occurred in the arterial phase in 5 cases and the peak value was seen in 17 cases in the portal phase. Eleven lesions invaded the gastric serosa, and lymphatic metastasis was observed in 21 cases, 8 of which were combined with liver metastasis. CT images revealed 2 cases of the liver metastasis had obvious enhancement.

CONCLUSION

The CT features regarding location, incidence rates of ulcer and enhancement pattern described in our findings are common in all malignant gastric tumors. Therefore, the diagnosis of G-NEC must be confirmed with pathological test.

Multimodality imaging of diseases of the duodenum

The duodenum is a unique segment of intestine, occupying both intra and extra-peritoneal locations. There is a wide spectrum of abnormalities of the duodenum that range from congenital anomalies to traumatic, inflammatory, and neoplastic entities. The duodenum may be overlooked on cross-sectional imaging due to its location and small size. Duodenal pathologies may, therefore, be missed or wrongly diagnosed. Knowledge about duodenal pathologies and optimal imaging techniques can increase diagnostic yield and permit optimal patient management. Conventionally, the duodenum was evaluated with upper GI studies on fluoroscopy; however, endoluminal evaluation is better performed with endoscopy. Additionally, a broad array of cross-sectional imaging modalities permits comprehensive assessment of the duodenum and surrounding viscera. While endoscopic sonography is increasingly used to locally stage duodenal malignancies, MDCT remains the primary modality widely used in the detection and characterization of duodenal abnormalities. MRI is used as a "problem solving" modality in select conditions. We present a comprehensive review of duodenal abnormalities with an emphasis on accurate diagnosis and management.

Gastric large cell neuroendocrine carcinoma with venous tumor thrombus: the value of PET/CT and contrast-enhanced computed tomography

Venous involvement is commonly detected microscopically on gastric neuroendocrine carcinomas (NECs), but related imaging studies have been rarely documented. We report a rare case of gastric large cell NEC with tumor thrombi in gastric and splenic veins, elevated serum alpha fetoprotein, and multiple hepatic nodules. In this case, (18)F-fluorodeoxyglucose positron emission tomography combined with contrast-enhanced computed tomography provided valuable information on tumor staging.

From the radiologic pathology archives: esophageal neoplasms: radiologic-pathologic correlation

Esophageal neoplasms have a wide spectrum of clinical features, pathologic findings, and imaging manifestations. Leiomyomas are the most common benign esophageal neoplasm, typically appearing as smoothly marginated intramural masses. Fibrovascular polyps arise in the cervical esophagus, gradually elongating as they are pulled inferiorly by esophageal peristalsis. Granular cell tumors are generally incidental small intramural masses with an appearance similar to that of leiomyomas. Malignant esophageal neoplasms are a common cause of cancer mortality, particularly squamous cell carcinoma (SCC) and adenocarcinoma. Both of these tumors occur in older men, most often appearing as irregular infiltrative lesions at barium examination, with evidence of tumor spread beyond the esophagus at cross-sectional imaging. Adenocarcinoma arises from Barrett esophagus and is much more likely than SCC to involve the gastroesophageal junction. Esophageal involvement by lymphoma is usually secondary to tumor spread from the stomach or mediastinum. Spindle cell carcinoma is a biphasic malignancy with carcinomatous and sarcomatous elements that forms a bulky polypoid intraluminal mass. Neuroendocrine carcinoma is an aggressive neoplasm that may be hypervascular and is usually associated with metastatic disease at presentation. Understanding the imaging appearances and pathologic bases of esophageal neoplasms is essential for their detection, differential diagnosis, staging, and treatment planning.