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

Abstract

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.

Keywords: adenocarcinoma; duodenal mass; duodenal metastasis from lung cancer; gastrointestinal metastasis; gastrointestinal metastasis from lung cancer; lung cancer; lung cancer with gastrointestinal metastasis; metastatic non-small cell lung cancer; non-small cell lung cancer; rare metastases.

Figure 1. Lung biopsy consistent with poorly differentiated adenocarcinoma at 40× magnification.

Figure 2. Contrast-enhanced computed tomography of the chest in axial view performed for initial staging showing a heterogeneously enhancing, lobulated, non-calcified right middle lobe mass closely abutting the cardiac border and measuring 4.0 × 3.1 × 2.3 cm. There is mild central low attenuation suggestive of necrosis.

Figure 3. Lateral radiograph of the right knee demonstrating an obliquely oriented, displaced, mildly angulated acute fracture (red arrow) of the right distal femoral metadiaphysis with overriding of the fracture fragments.

Figure 4. Anteroposterior radiograph of the right knee demonstrating an incidentally found lucent lesion with adjacent periosteal reaction within the proximal tibial diaphysis (red arrow).

Figure 5. Contrast-enhanced computed tomography in axial view taken after plain film radiography demonstrated a fracture showing a mixed attenuating fluid collection anterior to the femoral fracture, suggestive of hematoma formation (red arrow).

Figure 6. Duodenal biopsy consistent with adenocarcinoma.

Figure 7. Duodenal biopsy with positive thyroid transcription factor-1 immunohistochemical stain showing adenocarcinoma consistent with metastasis from lung primary.