Background: The prevalence of multiple primary malignant neoplasms (MPMNs) is increasing in parallel with the incidence of malignancies, the continual improvement of diagnostic models, and the extended life of patients with tumors, especially those of the digestive system. However, the co-existence of MPMNs and duodenal adenocarcinoma (DA) is rarely reported. In addition, there is a lack of comprehensive analysis of MPMNs regarding multi-omics and the tumor microenvironment (TME).
Case summary: In this article, we report the case of a 56-year-old man who presented with a complaint of chest discomfort and abdominal distension. The patient was diagnosed with metachronous esophageal squamous cell carcinoma and DA in the Department of Oncology. He underwent radical resection and chemotherapy for the esophageal tumor, as well as chemotherapy combined with a programmed death-1 inhibitor for the duodenal tumor. The overall survival was 16.6 mo. Extensive evaluation of the multi-omics and microenvironment features of primary and metastatic tumors was conducted to: (1) Identify the reasons responsible for the poor prognosis and treatment resistance in this case; and (2) Offer novel diagnostic and therapeutic approaches for MPMNs. This case demonstrated that the development of a second malignancy may be independent of the location of the first tumor. Thus, tumor recurrence (including metastases) should be distinguished from the second primary for an accurate diagnosis of MPMNs.
Conclusion: Multi-omics characteristics and the TME may facilitate treatment selection, improve efficacy, and assist in the prediction of prognosis.
Keywords: Case report; Duodenal adenocarcinoma; Esophageal tumor; Multi-omics; Multiple primary malignancies; Tumor microenvironment.
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