Primary Squamous Cell Biliary Carcinoma With Liver Metastasis Is Rare but Malicious

Primary squamous cell carcinoma (SCC) of the liver is quite rare, and to our knowledge, very few cases have been reported in the literature. The exact pathogenesis of the disease is unestablished; however, it is mostly reported to be associated with hepatic cyst, Caroli's disease, hepatolithiasis, hepatic cirrhosis, and hepatic teratoma. We report a case of a 50-year-old woman with no prior medical history initially, who presented with postprandial epigastric and right upper quadrant pain that continued to worsen and was associated with early satiety, nausea, and weight loss of 25 pounds over 2 months, which prompted further evaluation by her primary care physician. Magnetic resonance imaging (MRI) examination a month later revealed a large heterogeneous area measuring 8.5 × 2.4 × 7.4 cm in the inferior right hepatic lobe with heterogeneous enhancement and involvement of the gallbladder, concerning for cholangiocarcinoma. Given radiographic findings, she underwent a computed tomography (CT)-guided core biopsy of the liver, which showed a necrotic malignant tumor favoring adenocarcinoma and was also found to have germline BRCA mutation. A positron emission tomography (PET) scan revealed a large partially necrotic fluorodeoxyglucose (FDG) avid mass, possibly arising from the gallbladder fossa with an invasion of both lobes of the liver and probable involvement of a portion of the ascending colon. There was no gross evidence of distant metastatic disease. The patient underwent staging laparoscopy prior to initiating chemotherapy, and another biopsy was done, which returned in favor of SCC, with immunohistochemical stains being positive for cytokeratin (CK)19, Ber-EP4 (epithelial antigen recognized by Ber-EP4 antibody), and P40 (DeltaNp63); while negative for CK7, CK20, caudal-type homeobox 2 (CDX-2), paired box 8 (PAX-8), and mucicarmine. The patient started platinum-based chemotherapy due to germline BRCA mutation. However, due to complications associated with therapy and the progression of the disease, the patient eventually chose hospice. Primary SSC remains an unexplored aggressive malignancy that carries an overall poor prognosis. Diagnosis can be challenging and requires high clinical suspicion due to the scarcity in specific laboratory workup. Pathological diagnosis remains the gold standard; however, it also carries its own challenges. Treatment is usually case-oriented, and definitive protocols have yet to be established.