Unusual Metastasis of Signet-Ring Cell Gastric Cancer That Could Not Be Detected With 18 F-FDG PET But With 68 Ga-FAPI PET/CT.

ABSTRACT: A 70-year-old man who was scheduled for surgery because of the recurrence of gastric cancer was referred to our clinic preoperatively. The patient underwent a comprehensive evaluation through 18 F-FDG and 68 Ga-FAPI ( 68 Ga-labeled FAP inhibitors) PET/CT scans. The 68 Ga-FAPI PET/CT scan was particularly valuable in this case because of its ability to detect recurrent mass lesions and identify unusual metastatic sites compared with the 18 F-FDG PET/CT scan.

Comparison of 18 F-FDG and 18 F-FAPI PET/CT Findings of Signet-Ring Cell Carcinoma of the Stomach.

ABSTRACT: A 66-year-old man with gastric signet-ring cell carcinoma underwent both 18 F-FDG and 18 FAl-NOTA-FAPI PET/CT imaging. There was no abnormal FDG activity in the stomach, but there was diffuse intense 18 FAl-NOTA-FAPI uptake in the known lesion and an adjacent metastasis.

A rare cause of intestinal obstruction in children: signet-ring cell adenocarcinoma of the colon.

BACKGROUND: Signet-ring cell adenocarcinoma of the colon is well-recognized in adult patients who are extremely rare and not well-documented in children. Our study aims to raise awareness about this rare disease and its long-term outcomes. METHODS: We retrospectively evaluated patients with signet-ring cell colon adenocarcinoma. RESULTS: Six patients, three boys and three girls, with a mean age of 14.83 (range, 13-17 years), presented with signs of intesti-nal obstruction and were diagnosed with signet-ring cell colon adenocarcinoma. All patients had air-fluid levels on abdominal X-ray. Abdominal ultrasonography of all patients revealed subileus. Abdominal computed tomography was performed in five patients, and pre-operative colonoscopy was conducted in two patients before the emergency intervention. All of the patients underwent emergent exploratory laparotomy with the preliminary diagnosis of acute abdomen. In two patients, debulking surgery followed by a stoma was performed. The remaining four patients were treated with anastomosis following intestinal resection. All girls had metastases on the ovary. One of the patients died due to the burden of multiple metastases in the early period, and three died in the sixth post-operative year. We have been following the remaining two patients since then. CONCLUSION: Although signet-ring cell carcinomas (SRCCs) are rare, they should be considered in the differential diagnosis of acute abdomen and intestinal obstruction in pediatric patients. Despite early diagnosis and treatment, SRCC has a poor prognosis in the pediatric population.

Identification of gastric signet ring cell carcinoma based on endoscopic images using few-shot learning.

BACKGROUND: Deep learning (DL) models perform poorly when there are limited gastric signet ring cell carcinoma (SRCC) samples. Few-shot learning (FSL) can address the small sample problem. METHODS: EfficientNetV2-S was first pretrained on ImageNet and then pretrained on esophageal endoscopic images (i.e., base classes: normal vs. early cancer vs. advanced cancer) using transfer learning. Second, images of gastric benign ulcers, adenocarcinoma and SRCC, i.e., novel classes (n = 50 per class), were included. Image features were extracted as vectors using the dual pretrained EfficientNetV2-S. Finally, a k-nearest neighbor classifier was used to identify SRCC. The above proposed 3-way 3-shot FSL framework was conducted in three rounds. RESULTS: Dual pretrained FSL performed better than single pretrained FSL, endoscopists and traditional EfficientNetV2-S models. Dual pretrained FSL obtained the highest accuracy (79.4%), sensitivity (68.8%), recall (68.8%), precision (69.3%) and F1-score (0.691), and the senior endoscopist achieved the highest specificity of 93.6% when identifying SRCC. The macro-AUC and F1-score for dual pretraining (0.763 and 0.703, respectively) were higher than those for single pretraining (0.656 and 0.537, respectively), along with endoscopists and traditional EfficientNetV2-S models. The 2-way 3-shot FSL also performed better. CONCLUSION: The proposed FSL framework showed practical performance in the differentiation of SRCC on endoscopic images, suggesting the potential of FSL in the computer-aided diagnosis for rare diseases.

[A Case of Primary Signet Ring Cell Carcinoma of the Urinary Bladder Showing Effectiveness of Chemotherapy with Gemcitabine and Cisplatin].

A 55-year-old female presented to the hospital with a complaint of gross hematuria. Transurethral resection of bladder tumor was performed. The specimens pathologically showed signet ring cells and no urothelial carcinoma components. Magnetic resonance imaging and computed tomographic (CT) scan revealed bladder tumor, cervical metastasis, bilateral ovarian metastasis, and multiple lymph node metastasis. She was diagnosed with a primary signet ring cell carcinoma of the urinary bladder with cT3bN2M1, and was treated with chemotherapy of gemcitabine and cisplatin combination (GC). After 2 cycles of GC, the value of CEA which was elevated to 106 ng/ml before treatment, became negative. CT scan showed that her disease had successfully responded to the chemotherapy, and remained efficacious till the end of 6 cycles. The patient subsequently received 1 cycle of gemcitabine and nedaplatin and 3 cycles of avelumab due to renal insufficiency. Yet, 14 months after diagnosis, cerebellar metastases appeared and the patient died of meningeal carcinomatosis.

Factors associated with detection of hereditary diffuse gastric cancer on endoscopy in individuals with germline CDH1 mutations.

BACKGROUND AND AIMS: Individuals with germline pathogenic CDH1 variants have a high risk of hereditary diffuse gastric cancer. The sensitivity of EGD in detecting signet ring cell carcinoma (SRCC) in this population is low. We aimed to identify endoscopic findings and biopsy practices associated with detection of SRCC. METHODS: This retrospective cohort included individuals with a germline pathogenic/likely pathogenic CDH1 variant undergoing at least 1 EGD at Memorial Sloan Kettering Cancer Center between January 1, 2006, and March 25, 2022. The primary outcome was detection of SRCC on EGD. Findings on gastrectomy were also assessed. The study included periods before and after implementation of the Cambridge protocol for endoscopic surveillance, allowing for assessment of a spectrum of biopsy practices. RESULTS: Ninety-eight CDH1 patients underwent at least 1 EGD at our institution. SRCC was detected in 20 (20%) individuals on EGD overall and in 50 (86%) of the 58 patients undergoing gastrectomy. Most SRCC foci were detected in the gastric cardia/fundus (EGD, 50%; gastrectomy, 62%) and body/transition zone (EGD, 60%; gastrectomy, 62%). Biopsy results of gastric pale mucosal areas were associated with detection of SRCC (P < .01). The total number of biopsy samples taken on EGD was associated with increased detection of SRCC (P = .01), with 43% detected when ≥40 samples were taken. CONCLUSIONS: Targeted biopsy sampling of gastric pale mucosal areas and increasing number of biopsy samples taken on EGD were associated with detection of SRCC. SRCC foci were mostly detected in the proximal stomach, supporting updated endoscopic surveillance guidelines. Further studies are needed to refine endoscopic protocols to improve SRCC detection in this high-risk population.

The Correlation Between 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography Semiquantitative Parameters and the Clinical Features and Pathological Biological Indexes of Gastric Cancer.

Objective: This study explored the application value of the maximum standard uptake value (SUVmax) of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG PET/CT) in gastric cancer. Materials and Methods: Data of 164 patients with gastric cancer who had undergone18F-FDG PET/CT before a biopsy were collected, and the correlation of SUVmax with clinical stage, pathological differentiation degree, human epidermal growth factor receptor-2 (HER-2) status, and Ki-67 index of gastric cancer was analyzed. Results: The SUVmax of poorly differentiated adenocarcinoma was significantly higher than that of moderately differentiated adenocarcinoma and signet-ring cell carcinoma (p < 0.01), and SUVmax in the well-differentiated adenocarcinoma group was higher than that in the signet-ring cell carcinoma group (p < 0.01). The SUVmax in the HER-2 negative group was higher than that in the HER-2 positive group (p < 0.01). The SUVmax was higher in the Ki-67 high expression group than in the low expression group (p < 0.01), and there was a significant positive correlation between the two (p < 0.01). Conclusion: 18F-FDG PET/CT SUVmax can, to some extent, predict the degree of differentiation, HER-2 status, and Ki-67 index of gastric cancer patients.

Perirenal Infiltration of Signet Ring Cell Colon Carcinoma Shown by 68Ga-FAPI PET/CT.

ABSTRACT: A soft tissue lesion surrounding the left kidney was detected in 18F-FDG PET/CT performed with suspicion of recurrence in a patient who was operated for descending colon cancer and showed mild FDG uptake. Intense fibroblast activation protein-specific inhibitor (FAPI) uptake in the perirenal soft tissue was observed in 68Ga-FAPI-04 PET/CT. Tru-cut biopsy of the left perirenal lesion revealed signet ring cell colon carcinoma metastasis. This case demonstrated that 68Ga-FAPI-04 PET/CT could be a promising radiopharmaceutical for the evaluation of signet ring cell colon carcinomas.

Diagnosis and Management of Primary Prostatic Signet Ring Cell Carcinoma: Single-Center Experience.

The purpose of the study was to retrospectively summarize the diagnosis and management of 10 primary prostatic signet ring cell carcinoma (PPSRCC) cases in our center. Ten PPSRCC patients diagnosed at the First Affiliated Hospital of Nanjing Medical University from November 2014 to December 2020 were included. Clinical characteristics, image features, therapeutic procedures, histological diagnosis, and outcomes were retrospectively analyzed. All patients received prostate-specific antigen (PSA) examination preoperatively. Nine of them accepted multiparametric magnetic resonance imaging (mpMRI) due to elevated PSA value, and further biopsied. Among them, five patients were diagnosed as prostatic adenocarcinoma and the other four cases were found a mixture of signet ring cell carcinoma (SRCC) and adenocarcinoma. Furthermore, gastrointestinal endoscope and abdominal computed tomography (CT) did not find SRCC originating in gastrointestinal tract. Therefore, these cases were considered to be PPSRCC. Nine patients accepted laparoscopic or robot-assisted RP. Only one patient with normal PSA adopted transurethral resection of the prostate. Postoperative pathological results confirmed SRCC mixed with prostatic adenocarcinoma in nine cases, and only one patient with pure SRCC. After surgery, nine patients received adjuvant hormone therapy, one of which accepted radiotherapy simultaneously. The patient with pure SRCC did not accept any adjuvant therapy postoperatively. During a mean follow-up of 31.9 months, only four patients were alive without disease progression. In summary, PPSRCC is a rare malignant tumor with few specific symptoms, rapid disease progression, and poor prognosis and is frequently accompanied by high-grade prostate adenocarcinoma patterns. There is still no clear and effective strategy to improve the prognosis.

[Late recurrence of gastric cancer diagnosed 10 years after curative gastrectomy: a review of 30 Japanese case reports].

A woman in her 50s was referred to our hospital with intestinal obstruction. Ten years prior, she had been treated for gastric cancer, pathologically confirmed as stage IIIA poorly differentiated adenocarcinoma with signet-ring cell carcinoma. Intraoperatively, a 4-cm hard white tumor was found in the mesoileum and around the ileum. Pathological examination revealed poorly differentiated adenocarcinoma with signet-ring cell carcinoma and infiltration and fibrosis. Late peritoneal recurrence of gastric carcinoma was diagnosed. Recurrence of gastric carcinoma more than 10 years after curative gastrectomy is extremely rare. A review of 30 cases reported in Japan revealed recurrence was more frequent in females (60%) and the mean age was around 50 years at the time of primary surgery. Poorly differentiated adenocarcinoma and/or signet-ring cell carcinoma was the primary gastric cancer in 82% of cases and bone metastasis was the most frequent site of recurrence.

CT-based radiomics nomograms for preoperative prediction of diffuse-type and signet ring cell gastric cancer: a multicenter development and validation cohort.

BACKGROUND: The prevalence of diffuse-type gastric cancer (GC), especially signet ring cell carcinoma (SRCC), has shown an upward trend in the past decades. This study aimed to develop computed tomography (CT) based radiomics nomograms to distinguish diffuse-type and SRCC GC preoperatively. METHODS: A total of 693 GC patients from two centers were retrospectively analyzed and divided into training, internal validation and external validation cohorts. Radiomics features were extracted from CT images, and the Lauren radiomics model was established with a support vector machine (SVM) classifier to identify diffuse-type GC. The Lauren radiomics nomogram integrating radiomics features score (Rad-score) and clinicopathological characteristics were developed and evaluated regarding prediction ability. Further, the SRCC radiomics nomogram designed to identify SRCC from diffuse-type GC was developed and evaluated following the same procedures. RESULTS: Multivariate analysis revealed that Rad-scores was significantly associated with diffuse-type GC and SRCC (p < 0.001). The Lauren radiomics nomogram showed promising prediction performance with an area under the curve (AUC) of 0.895 (95%CI, 0.957-0.932), 0.841 (95%CI, 0.781-0.901) and 0.893 (95%CI, 0.831-0.955) in each cohort. The SRCC radiomics nomogram also showed good discrimination, with AUC of 0.905 (95%CI,0.866-0.944), 0.845 (95%CI, 0.775-0.915) and 0.918 (95%CI, 0.842-0.994) in each cohort. The radiomics nomograms showed great model fitness and clinical usefulness by calibration curve and decision curve analysis. CONCLUSION: Our CT-based radiomics nomograms had the ability to identify the diffuse-type and SRCC GC, providing a non-invasive, efficient and preoperative diagnosis method. They may help guide preoperative clinical decision-making and benefit GC patients in the future.

Deep learning-based AI model for signet-ring cell carcinoma diagnosis and chemotherapy response prediction in gastric cancer.

PURPOSE: We aimed to develop a noninvasive artificial intelligence (AI) model to diagnose signet-ring cell carcinoma (SRCC) of gastric cancer (GC) and identify patients with SRCC who could benefit from postoperative chemotherapy based on preoperative contrast-enhanced computed tomography (CT). METHODS: A total of 855 GC patients with 855 single GCs were included, of which 249 patients were diagnosed as SRCC by histopathologic examinations. The AI model was generated with clinical, handcrafted radiomic, and deep learning features. Model diagnostic performance was measured by area under the receiver operating characteristic curve (AUC), sensitivity, and specificity, while predictive performance was measured by Kaplan-Meier curves. RESULTS: In the test cohort (n = 257), the AUC, sensitivity, and specificity of our AI model for diagnosing SRCC were 0.786 (95% CI: 0.721-0.845), 77.3%, and 69.2%, respectively. For the entire cohort, patients with AI-predicted high risk had a significantly shorter median OS compared with those with low risk (median overall survival [OS], 38.8 vs. 64.2 months, p = 0.009). Importantly, in pathologically confirmed advanced SRCC patients, AI-predicted high-risk status was indicative of a shorter overall survival (median overall survival [OS], 31.0 vs. 54.4 months, p = 0.036) and marked chemotherapy resistance, whereas AI-predicted low-risk status had substantial chemotherapy benefit (median OS [without vs. with chemotherapy], 26.0 vs. not reached, p = 0.013). CONCLUSIONS: The CT-based AI model demonstrated good performance for diagnosing SRCC, stratifying patient prognosis, and predicting chemotherapy responses. Advanced SRCC patients with AI-predicted low-risk status may benefit substantially from adjuvant chemotherapy.

Signet ring cell carcinoma of bladder: a dilemma between primary and metastatic.

Signet ring cell carcinoma, in general, is a peculiar tumour. There is always a query regarding its exact site of origin. Even, immunohistochemistry shows overlapping staining patterns between various sites. On one hand, signet ring cell carcinoma of the bladder is a rare occurrence, but on the other hand metastatic signet ring cell carcinoma to the bladder is not uncommon. However, without prior knowledge of the primary site of tumour clinically and radiologically, definitive diagnosis is challenging based on morphology and immunohistochemistry.

Comparison of 18F-AlF-NOTA-FAPI and 18F-FDG Imaging in a Patient With Gastric Signet-Ring Cell Carcinoma.

ABSTRACT: Several case reports have shown fibroblast activation protein inhibitor (FAPI) imaging to be superior to 18F-FDG imaging in the delineation of primary gastric signet-ring cell carcinoma lesions. In this case, 18F-AlF-NOTA-FAPI PET/CT showed more metastatic lesions that had more increased activity than 18F-FDG PET/CT. However, neither 18F-AlF-NOTA-FAPI nor 18F-FDG imaging revealed any abnormal uptake in the primary gastric lesion, which was subsequently demonstrated to be the primary lesion by pathology.