Appendiceal intussusception complicated by adenocarcinoma of the cecum: A case report.

BACKGROUND: Appendiceal intussusception is a pathological condition in which the appendix is inverted into the cecum, which may cause symptoms that resemble those of other gastrointestinal disorders and may induce intestinal obstruction. The rarity of this case presentation is the co-occurrence of appendiceal intussusception and cecal adenocarcinoma, a combination that to our knowledge has not previously been reported in the medical literature. This case provides new insights into the complexities of diagnosing and managing overlapping pathologies. CASE SUMMARY: A 25-year-old woman presented with persistent periumbilical pain and bloody stools. An initial biopsy showed cecal cancer; however, subsequent colonoscopy and computed tomography findings raised the suspicion of appendiceal intussusception, which was later confirmed postoperatively. This unique case was characterized by a combination of intussusception and adenocarcinoma of the cecum. The intervention included a laparoscopic right hemicolectomy, which led to the histopathological diagnosis of mucinous adenocarcinoma with appendiceal intussusception. The patient recovered well postoperatively and was advised to initiate adjuvant chemotherapy. This case highlights not only the importance of considering appendiceal intussusception in the differential diagnosis, but also the possibility of appendicitis and the atypical presentation of neoplastic lesions. CONCLUSIONS: Physicians should consider the possibility of appendiceal intussusception in cases of atypical appendicitis, particularly when associated with neoplastic presentation.

Synchronous Double Primary Malignant Tumors and their Possible Shared Genes: A Rare Clinical Entity.

Objective: This study sought to analyze the 18F-FDG PET/CT and contrast-enhanced computed tomography (CT) images of synchronous colorectal cancer (CRC) and renal clear cell carcinoma (ccRCC) and identify the shared genes between these two types of cancer through bioinformatic analysis. Methods: A retrospective analysis was conducted on a patient with synchronous CRC and ccRCC who underwent 18F-FDG PET/CT and contrast-enhanced CT before treatment. Databases were analyzed to identify differentially expressed genes between CRC and ccRCC, and co-expression genes were extracted for RCC and CRC. Results: 18F-FDG PET/CT revealed intense metabolic activity in the primary colorectal lesion (SUVmax 13.2), while a left renal mass (diameter = 35 mm) was observed with no significant uptake. Contrast-enhanced CT during the arterial phase showed heterogeneous intense enhancement of the renal lesion, and the lesion washed out earlier than in the renal cortex in the nephrographic and excretory phases, indicating ccRCC. The histopathological results confirmed synchronous double primary malignant tumors. Our bioinformatic analysis results showed that synchronous occurrence of CRC and ccRCC may correlate with simultaneous expression of Carbonic Anhydrase 9 (CA9), integrin-binding sialoprotein (IBSP), and Fibrinogen γ chain (FGG). Conclusion: 18F-FDG PET/CT combined with contrast-enhanced CT is an effective diagnostic tool in evaluating synchronous CRC and RCC. By analyzing this clinical case and conducting bioinformatic analysis, we improved our current understanding of the mechanisms underlying synchronous tumors.

Dickkopf-related protein 1/cytoskeleton-associated protein 4 signaling activation by Helicobacter pylori-induced activator protein-1 promotes gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

BACKGROUND: Gastric cancer (GC) is a common malignant tumor with high incidence and mortality rates globally, especially in East Asian countries. Helicobacter pylori (H. pylori) infection is a significant and independent risk factor for GC. However, its underlying mechanism of action is not fully understood. Dickkopf-related protein (DKK) 1 is a Wnt signaling antagonist, and cytoskeleton-associated protein (CKAP) 4 is a newly identified DKK1 receptor. Recent studies found that the binding of DKK1 to CAKP4 mediated the procancer signaling of DKK1 inde-pendent of Wnt signaling. We hypothesize that H. pylori-induced activation of DKK1/CKAP4 signaling contributes to the initiation and progression of GC. AIM: To investigate the interaction of H. pylori infection, DKK1 and CAKP4 in GC, as well as the underlying molecular mechanisms. METHODS: RNA sequencing was used to identify differentially expressed genes (DEGs) between H. pylori-infected and uninfected primary GC cells. Gain- and loss-of-function experiments were performed to verify the H. pylori-induced upregulation of activator protein-1 (AP-1) in GC cells. A dual-luciferase reporter assay and co-immunoprecipitation were used to determine the binding of AP-1 to the DKK1 promoter and DKK1 to CKAP4. Western blotting and immunohistochemistry detected the expression of DKK1, CKAP4, and phos-phatidylinositol 3-kinase (PI3K) pathway-related proteins in GC cells and tissues. Functional experiments and tumorigenicity in nude mice detected malignant behavior of GC cells in vitro and in vivo. RESULTS: We identified 32 DEGs between primary GC cells with and without H. pylori infection, including JUN, fos-like antigen-1 (FOSL1), and DKK1, and confirmed that the three proteins and CKAP4 were highly expressed in H. pylori-infected GC cells, H. pylori-infected gerbil gastric tissues, and human GC tissues. JUN and FOSL1 form AP-1 to transcriptionally activate DKK1 expression by binding to the DKK1 promoter. Activated DKK1 bound to CKAP4, but not the most common Wnt coreceptor low-density lipoprotein receptor-related protein 5/6, to promote GC cell growth, colony formation, migration, invasion, and xenograft tumor growth in nude mice. All these effects were driven by activation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway. Targeting the PI3K signaling pathway by LY294002 inhibited DKK1-mediated CKAP4/PI3K signaling activity and the malignant behavior of GC cells. CONCLUSION: H. pylori induces JUN and FOSL1 expression to form AP-1, which transcriptionally activates DKK1. Binding of DKK1 to KAKP4 contributes to gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

Plexiform fibromyxoma of the small bowel: A case report.

BACKGROUND: Plexiform fibromyxoma is a rare, special type of mesenchymal tumor. The most common presenting symptoms are anemia, hematemesis, and hematochezia, without sex or age predilection. The reported cases have mainly occurred in the gastric antrum and pylorus region, with some cases in the duodenum. CASE SUMMARY: We report here a case of plexiform fibromyxoma in the upper segment of the jejunum, which was continuously followed up for 3 years after surgical removal. Plexiform fibromyxoma showed multinodular or plexiform growth. The cells in the tumor node were spindle-shaped but few in number and mitotic figures. Small blood vessels and mucous matrix were found among the tumor cells. Immunohistochemistry revealed that the plexiform fibromyxoma cells were positive for smooth muscle actin, focally positive for CD10, and negative for cytokeratin, CD117, DOG-1 (discovered on GIST-1) desmin, S-100, epithelial membrane antigen, and CD34. Ki-67 labeling index was < 5%. Plexiform fibromyxoma showed benign biological behavior. After 3 years of consecutive postoperative follow-up, no obvious signs of metastasis or recurrence were found by imaging examination. CONCLUSION: Plexiform fibromyxoma is a rare type of mesenchymal tumor. The diagnosis mainly depends on pathological examination, and it should be distinguished from other gastrointestinal mesenchymal tumors.

[Ultrastructural features and platelet-derived growth factor receptor A gene mutations in CD117-negative gastrointestinal stromal tumor].

OBJECTIVE: To explore the ultrastructural features and mutation status of platelet-derived growth factor receptors A (PDGFRA) and c-kit in gastrointestinal stromal tumors that were immunohistochemically negative for CD117 antigen. METHODS: Six cases of gastrointestinal stromal tumors that were CD117 immunostain negative were studied by electron microscopy. Direct PCR sequencing was used to investigate the mutation status of c-kit gene exons 9, 11, 13, 17 and PDGFRA gene exons 12 and 18. RESULTS: The ultrastructural features of all 6 cases were similar to those of the interstitial cell of Cajal (ICC). None of the 6 cases were found to have c-kit gene mutations. However, three tumors were found to harbor PDGFRA exon 18 activating mutations, including two tumors having an Asp-->Val842 missense mutation and one having an Arg-->Ser841 missense mutation. CONCLUSIONS: PDGFRA mutations may provide an important alternative molecular mechanism for the development of gastrointestinal stromal tumor.

[The clinical significance of p16 protein non-expression and p16 gene inactivation by deletions and hypermethylation in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the clinical significance of p16 protein non-expression and p16 gene inactivation by deletions and hypermethylation in nasopharyngeal carcinoma. METHODS: Immunohistochemical study for p16 protein was carried out in 90 cases of non-keratinizing carcinoma (NKC) of nasopharynx. P16 gene deletions and hypermethylation were also analyzed by polymerase chain reaction (PCR) and methylation-specific PCR in 23 randomly selected NKC cases. RESULTS: Among the 90 NKC cases studied, 42 cases (46.7%) were negative for p16 protein. The non-expression rate of p16 protein also correlated with the 5-year survival rate. The non-expression rate was 60.0% in patients who died within 5 years, in contrast to 20.0% in those alive for over 5 years after diagnosis. The non-expression rate of p16 protein in cases with or without distant metastasis was 81.8% and 41.8% respectively (P < 0.05), while that in cases with or without local invasion into skull base was 41.7% and 48.5% respectively (P > 0.05). As for molecular analysis, deletion of p16 gene exon 2 was found in 10 of the 23 cases (43.4%) studied, while deletion of p16 gene exon 1 was not detected in these samples. Hypermethylation of p16 gene exon 1 was also noted in 2 of the 23 cases (8.7%). The overall mutation rate of these cases was 52.1%. CONCLUSIONS: There is a high incidence of p16 protein non-expression, deletion of p16 gene exon 2 and hypermethylation of p16 gene exon 1 in NKC. P16 gene inactivation may thus play an important role in the pathogenesis of NKC, especially in terms of its metastatic potential.

[c-kit and PDGFRA mutations in 60 cases of gastrointestinal stromal tumors (GISTs)].

OBJECTIVE: To explore the status of activating mutations of c-kit and PDGFRA in GIST of Chinese patients. METHODS: Sixty GISTs, confirmed by immunoreactivity of CD117, CD34, SMA, S-100 and Desmin, were evaluated for the presence of c-kit exons 9, 11, 13 and 17 mutations, and PDGFRA exons 12 and 18 mutations. The PCR products were sequenced directly for mutations, using DNA extracted from paraffin-embedded tissue. RESULTS: 53% of the tumors were located in the stomach, 22% in the small bowel, 8% in the colo rectum, 2% in the esophagus and 15% in the extragastrointestinal tract. Immunohistochemical demonstrations of c-kit (CD117) were seen in 90% cases. Overall, c-kit mutations were detected in 63.3% of patients as follows: 58.3% in exon 11, 3.3% in exon 9, 1.7% in exon 13 and none in exon 17. The types of c-kit exon 11 mutations were mostly heterogeneous and clustered in the classic "hot spot" at the 5' end of exon 11, 42.9% being point mutation and in-frame deletion at Codon 557-560. 14.3% of cases showed internal tandem duplications (ITD) at the 3' end of exon 11 in a region of a second hot spot for c-kit mutations. Interestingly, these cases were associated with female predominance, stomach location and occurrence in older patients. The present study failed to identify a significant association between c-kit mutation status and risk of aggressive behavior in GISTs. Exon 9 mutations consisted of ITP of six nucleotides encoding Ala-Tyr. A new point mutation of L641P was revealed in exon 13. PDGFRA mutations were found in 5% of all the 60 cases with none of the positive cases expressed detectable KIT protein. The type of mutation was the commonest point mutation of D842V of exon 18. CONCLUSION: Most KIT expressing GIST show c-kit mutations that are preferentially located within the classic hot spot of exon 11. A second hot spot -ITD at the 3' end of exon 11 seems to associate with a subgroup of gastric GISTs in older females. c-kit exons 9, 13 and 17 mutations are rare events in GIST of China. PDGFRA oncogenic mutations are more likely seen in KIT-negative GISTs arising in the peritoneal surface and have an unfavorable clinical course.