1443 Hypercalcemia as the First Presentation of an Underlying Rare Variant of Adenosquamous Cholangiocarcinoma

Abstract

INTRODUCTION: Humoral hypercalcemia of malignancy (HHM) is an important paraneoplastic syndrome which is caused by the over secretion of the parathyroid hormone-related peptide (PTHrP) from a variety of cancers. Most commonly HHM is reported in squamous cell carcinomas of the lung, head, neck, skin, esophagus, ovarian and breast cancer. HHM due to intrahepatic cholangiocarcinoma is a rare association and is associated with poor prognosis. CASE DESCRIPTION/METHODS: We herein report a case of hypercalcemia presenting as the first presentation of an underlying rare variant of intrahepatic cholangiocarcinoma. Our patient is a 57-year-old male who presented to the emergency room with severe constipation and polyuria. His physical examination was unremarkable except for hepatomegaly. His laboratory values revealed calcium 16.5 mg/dL, creatinine 1.37 mg/dL, ALP of 413 U/L, PTH -2 pg/mL, PTHrP 82 pg/mL. Computed tomography (CT) of the abdomen revealed a 15 cm liver mass with possible satellite lesions. The patient was subsequently treated for symptomatic hypercalcemia with aggressive hydration, zoledronic acid, and calcitonin. Biopsy of the liver lesion revealed poorly differentiated carcinoma with squamous features positive for Immunohistochemical markers CEA, CK19, P63, CK5/6, CK7 which favored pancreaticobiliary malignancy as the primary. Further staging scan with positron emission tomography (PET) revealed extensive hypermetabolic activity in the liver, enlarged upper abdominal lymph nodes, nodularity of the omentum/peritoneum and ascites inferior to the liver. Within a week into the presentation, his bilirubin started to increase, needing emergency percutaneous transhepatic cholangiography (PTC). His repeat CT scans showed progressively increasing tumor size to 19 cm with an associated increase in satellite lesions. This necessitated an urgent inpatient treatment with gemcitabine/cisplatin combination chemotherapy to control the aggressive nature of the malignancy. DISCUSSION: Adenosquamous cholangiocarcinoma is a very rare variant accounting for <2% of all liver tumors. It develops due to squamous metaplasia of an underlying cholangiocarcinoma and usually has aggressive clinicopathological features. HMM is a life-threatening yet unrecognized phenomenon of cholangiocarcinoma which represents a poor prognostic marker. Prompt recognition of this complication is important for preventing serious complications associated with hypercalcemia and to improve the quality of life of these patients.