A case of pancreatic endocrine carcinoma with a different clinical diagnosis before chemotherapy and pathological autopsy

Abstract

We encountered a case of pancreatic neuroendocrine carcinoma (pNEC) diagnosed via pathological autopsy that was initially diagnosed clinically as G3 pancreatic neuroendocrine tumor (G3 pNET) and discussed the differences between these entities in the literature. A 76-year-old man was admitted to our department because of jaundice. Computed tomography revealed multiple round nodules in both lung fields, suggesting metastasis, and a mass lesion was detected in the head of the pancreas with poor contrast in the arterial phase and slight contrast enhancement in the equilibrium phase. Biopsy of the lungs and pancreas led to a diagnosis of multiple pulmonary metastases of G3 pNET. Because the lesions were unresectable, chemotherapy was administered. Treatment was started with everolimus for 5 weeks. However, the patient experienced severe loss of appetite and malaise, and the lung lesions progressed, prompting treatment discontinuation. Subsequently, the patient’s disease progressed rapidly, and he died 99 days after the start of chemotherapy. We performed a pathological autopsy with the consent of the family because of the rapid tumor growth. A pathological autopsy revealed a final diagnosis of pNEC, which differed from the clinical diagnosis.