S5589 Small Cells but Scrappy: A Rare Case of Hepatic Small Cell Neuroendocrine Carcinoma

Introduction: Small cell carcinoma (SCC) is a cancer that is most seen in the lungs; however, it has been found in extrapulmonary sites. Extrapulmonary SCC (EPSCC) has an aggressive natural history and is characterized by early widespread metastasis. Patients with EPSCC may show signs of improvement with initial therapies however, most will experience relapse and the overall prognosis is poor. Recent studies have revealed that less than 15% of patients with EPSCC will reach 5-year survival. We present a unique case of a patient with prostate adenocarcinoma who developed a new hepatic small cell neuroendocrine carcinoma. Case Description/Methods: A 70-year-old African American male presented to the emergency room for abdominal pain and constipation. He had a past medical history significant for hypertension and prostate adenocarcinoma status post chemotherapy and radiation. He was jaundiced and had scleral icterus. Initial labs were significant for transaminitis, hyperbilirubinemia, and elevated alkaline phosphatase. Abdominal imaging revealed multiple hepatic masses as well as intra- and extrahepatic biliary ductal dilation. Patient underwent biliary sphincterotomy with common bile duct stenting, and liver biopsies were obtained. Biopsy results came back as hepatic small cell neuroendocrine transformation of his prostate adenocarcinoma. He was started on radiation therapy as well as carboplatin and etoposide combination chemotherapy. Unfortunately, the patient displayed worsening symptoms in the months to come and repeat imaging revealed worsening metastasis of his cancer. The patient ultimately passed away a few months after initial diagnosis. Discussion: EPSCC is extremely rare, currently there are very few reported cases of liver involvement. The initial clinical manifestations of EPSCC are typically due to locoregional disease and presenting symptoms may be indistinguishable from different tumors arising from the same site. Tumor-associated neuroendocrine markers have been shown to be high in some cases, however no studies have shown any utility to measuring or monitoring these markers. Currently, the mainstay of treatment is a platinum-based regimen with etoposide, as was used in our patient. Despite aggressive systemic chemotherapy, most patients with EPSCC will develop metastatic disease and the prognosis is poor. This case highlights how aggressive EPSCC can be despite locoregional and systemic therapy and the need for additional research to improve outcomes for these patients.