Incidental Metastatic High-Grade Neuroendocrine Carcinoma Diagnosed by Liver Biopsy During Cholecystectomy: A Case Report

Neuroendocrine neoplasms range from relatively indolent well-differentiated tumors to aggressive poorly differentiated neuroendocrine carcinomas (NECs).Diagnosis can be challenging when nonspecific symptoms coexist with another disease that provides a plausible explanation for the presentation.A 70-year-old woman developed nausea, vomiting, and epigastric abdominal pain several weeks after pelvic reconstructive surgery.Evaluation demonstrated abnormal liver tests, cholelithiasis, and a heterogeneous nodular liver initially concerning for cirrhosis.Magnetic resonance cholangiopancreatography showed no choledocholithiasis or significant biliary dilation.She underwent laparoscopic cholecystectomy with liver wedge biopsy.Gallbladder pathology confirmed chronic cholecystitis, cholelithiasis, and porcelain gallbladder; unexpectedly, the liver biopsy demonstrated high-grade NEC, small-cell type.Persistent abdominal pain and cholestatic liver abnormalities after cholecystectomy prompted further evaluation.Staging demonstrated extensive hepatic involvement, a right middle-lobe pulmonary lesion, bulky mediastinal and hilar lymphadenopathy, and multifocal osseous metastatic disease.The overall pattern favored metastatic small-cell NEC of pulmonary origin, although the thoracic disease was not biopsied in the available records.She received carboplatin and etoposide, later with atezolizumab, but developed neutropenia, pneumonia, recurrent hospitalizations, progressive cancer-related pain, weight loss, and worsening metastatic disease.With progressive hepatic and osseous disease, declining functional status, and worsening hepatic dysfunction, she ultimately elected comfort-focused treatment and home hospice.This case demonstrates how an aggressive metastatic malignancy can remain obscured by legitimate concurrent diagnoses.Persistence of findings unexplained by the initial diagnosis and failure to improve as expected after appropriate treatment should prompt diagnostic reassessment.