Delayed Diagnosis of Duodenal Metastasis From Primary Lung Adenocarcinoma: A Case Report

The incidence of lung cancer metastasizing to the duodenum is rare, and its clinical presentation is still not fully understood due to its low frequency. It can be asymptomatic or present symptomatically in various ways. Here, we present the case of a 63-year-old female with an unusual case of duodenal metastasis from pulmonary adenocarcinoma, presenting with a new-onset seizure complicated by a fracture from a post-ictal fall. The diagnosis of anemia secondary to duodenal metastasis from lung cancer was delayed due to this sequence of events. The patient was ultimately found to have a circumferential mass in the third portion of the duodenum on esophagogastroduodenoscopy, which was found to be consistent with metastatic pulmonary adenocarcinoma on pathological examination.