2661 A Rare Case of Poorly Differentiated Lung Carcinoma With Duodenal Metastasis

Abstract

INTRODUCTION: Lung cancer metastasis to the gastrointestinal (GI) tract is uncommon, with the duodenum being particularly rare. We present a unique case of a 61-year-old male with a history of lung cancer, who was found to have a metastatic mass on esophagogastroduodenoscopy (EGD) that was histologically similar to his lung cancer, ultimately being a diagnosis of poorly differentiated carcinoma (PDC) with focal neuroendocrine differentiation (FND). CASE DESCRIPTION/METHODS: 61-year-old male presented with 1 month of worsening dizziness, fatigue, and early satiety. On physical exam, he was tachycardic with a blood pressure of 92/60. Labs were notable for a Hgb of 7.2 (baseline of 12). Of note, 6 months prior, he was having hemoptysis and was found to have a left apical lesion on computerized tomography (CT) scan of the chest. Results from a fine needle aspiration (FNA) of the mass showed PDC that was weakly positive for CK-7, and synaptophysin on immunohistochemical staining (IHCS); thus, he was started on chemoradiation therapy. His EGD showed an oozing ulcer in the third portion of the duodenum with heaped up borders. Bipolar cautery was performed, and biopsies were obtained which showed PDC, histologically and immunohistochemically similar to his previous lung biopsy. The patient’s Hgb continued to drop during the hospital course requiring multiple transfusions, and ultimately, a gastroduodenal artery embolization. He was eventually discharged after monitoring his hemodynamics, with close outpatient follow up, as he wanted to pursue continued medical management. DISCUSSION: The results of the lung FNA showed sheets of atypical cells with focal necrosis, and prominent nucleoli being dispersed without a specific pattern, consistent with a diagnosis of PDC with FND. IHCS was weakly positive (very few scattered cells) for CK-7, and synaptophysin but negative for CK-20, P63, TTF-1, chromogranin, and CDX2. The duodenal mass biopsy showed PDC with IHCS negative for CK-7, synaptophysin, CK-20, P63, P40, Napsin-A, P40, CDX-2, TTF-1, chromogranin, calretinin, CD20, and CD3; making it histologically similar to his previous lung biopsy. The IHCS of both biopsies could not identify a specific type of carcinoma and histological analysis only showed areas of FND; highlighting the unique aspect of this case. Treatment of duodenal metastasis is challenging and depends on many variables. He was deemed a poor surgical candidate due to his comorbidities/metastatic disease and eventually had a palliative embolization.