S3332 An Unusual Case of Aggressive Prostate Cancer With Liver Metastasis in a Patient With Ulcerative Colitis and Total Colectomy

Abstract

Introduction: Prostate cancer is a relatively slow-growing with 96.8% 5-year survival rate. Less than 7% of patients are found to have aggressive cancer with metastasis to distant sites, such as: bone, lymph nodes, liver and thorax. The incidence of prostate cancer in the 45-54 year age group is merely 7.2% and median age at diagnosis is 67 years. We present a rare case of a 51-year old patient found to have liver metastasis of prostate origin, which was initially thought to be of gastrointestinal origin given elevated Carcinoembryonic Antigen (CEA) and CA 19-9. Case Description/Methods: A 51-year-old male patient with history of ulcerative colitis status post total colectomy thirty years prior, presented with progressive abdominal distension and unintentional twenty pound weight loss over a two month period. Physical exam revealed a mild jaundice, non-tender distended abdomen with palpable hepato-splenomegaly. Routine laboratory revealed normal complete blood count, with liver function elevation: total bilirubin 3.8, direct bilirubin 3, ALP 722, ALT 112, and AST 395. Computed tomography (CT) scan of the abdomen and pelvis without contrast showed findings concerning for metastatic disease with innumerable hepatic mass lesions, and lymphadenopathy. Cancer markers obtained showed normal AFP, however elevated Chromogranin A, CEA and CA 19-9, at 111 ng/mL, 741 ng/mL and 892 ng/mL, respectively. While initially a gastrointestinal origin of cancer was suspected, a liver biopsy was performed which revealed a poorly differentiated adenocarcinoma of prostate origin with positive staining for NKX3.1 and elevated PSA. (Figure) Discussion: Prostate cancer is the second most frequent malignancy in men worldwide and second leading cause of male-cancer related death in the United States, yet has favorable survival rates. The most common tumor marker for prostate carcinoma is serum PSA, however there is no current guideline recommending periodic PSA measurements. Elevated levels of CEA and CA 19-9 in the setting of metastatic prostate cancer have rarely been reported in literature, with merely eight known other cases. Given patient’s underlying history of ulcerative colitis, suspicion for cholangiocarcinoma would have been high on differential and in this case liver biopsy would be contraindicated. Our case highlights a rare presentation of liver metastasis and highlights importance of keeping broad differential. Importantly, liver metastatic burden is of concern and limiting factor when choosing immunotherapy or chemotherapy.Figure 1.: Computed tomography (CT) image of the abdomen, showing innumerable hypodense hepatic mass lesions (white arrows), with the largest in the right hepatic lobe measuring up to 5.4 x 5.0 cm indicated by red arrow.