Metastatic Small Cell Neuroendocrine Carcinoma Presenting with Liver Metastasis

A 72-year-old female presented with weight loss and poor oral intake.Multiple hepatic masses and enlarged lymph nodes (LNs) observed on imaging raised the suspicion of metastatic disease.Esophagogastroduodenoscopy and colonoscopy were unremarkable.Liver biopsy confirmed the diagnosis of metastatic small cell neuroendocrine carcinoma, with immunohistochemistry (IHC) findings indicative of the primary tumor being from the lungs (CK [AE1/3]+, TTF-1+, INSM1+, CD45-, Vimentin-).Widespread metastases to the liver, LNs, and bones were evident on positron emission tomography-computed tomography.The patient underwent four cycles of chemotherapy with etoposide and cisplatin (EP regimen); however, pneumonia and anemia complicated the treatment and the patient had to be referred to hospice care.This case highlights the importance of IHC in diagnosing metastatic disease and the challenges of managing extensive metastases in elderly patients with comorbidities.