Identification of a Microsatellite Stable, EGFR-Mutant Lung Adenocarcinoma Developing in a Patient With Lynch Syndrome

Lung adenocarcinoma in a patient with Lynch syndrome: a case report and literature review

This article presents a case of a 62-year-old Vietnamese woman with a history of Lynch syndrome (LS), who developed lung adenocarcinoma with EGFR L858R mutation. LS is an autosomal dominant cancer predisposition syndrome caused by a pathogenic germline variant in DNA mismatch repair genes, often leading to microsatellite instability. While LS is primarily associated with gastrointestinal, endometrial, ovarian, and urologic tract cancers, lung cancer accounts for less than 1% of LS-related cancers, with only six cases of LS-related lung cancer previously reported in the literature. The patient underwent multiple lines of treatment for her lung adenocarcinoma, including tyrosine kinase inhibitors, stereotactic body radiation therapy, pemetrexed and pembrolizumab, amivantamab, and fam-trastuzumab deruxtecan, but all resulted in only a partial response followed by a progressive disease. This case highlights the complex interplay of genetic cancer predisposition syndromes and the development of spontaneous driver mutations in the disease course and the subsequent management of tumors arising in these patients.

Nonbacterial thrombotic endocarditis in a patient with gastric cancer and SARS-CoV-2 infection

Nonbacterial thrombotic endocarditis, formerly known as marantic endocarditis, is a very rare complication of advanced malignancy and other hypercoagulable states in which sterile, fibrin vegetations develop on heart valve leaflets. The most common malignancies associated with this entity are lung, pancreatic and gastric cancer. It has also been described as a presentation of COVID-19, which is known to be frequently complicated with coagulopathy and thromboembolic events. We report the case of a 62 year-old female patient newly diagnosed with stage IV gastric cancer and acute SARS-CoV-2 infection, presenting with confusion and homonymous hemianopsia in the setting of multiple acute ischemic strokes complicating a nonbacterial thrombotic mitral endocarditis. Herein, we discuss the underlying pathophysiology and make the hypothesis that SARS-CoV-2 infection could have participated in the pathogenesis of nonbacterial thrombotic endocarditis in our patient suffering from a gastric cancer.