Introduction A biloma is a loculated accumulation of bile outside of the biliary tree; it can either be intrahepatic or extrahepatic. They are usually caused by trauma, iatrogenic procedures like endoscopic retrograde cholangiopancreatography (ERCP), laparoscopic cholecystectomy, percutaneous procedures like transcatheter arterial chemoembolization, microwave ablation, or percutaneous biliary drainage. We are presenting a case of a 78-year-old male with an incidental diagnosis of large biloma noted on CT scan which was obtained for routine lung cancer screening. Case presentation A 78-year-old male with a past medical history of prostate cancer and diabetes was admitted to the hospital after a routine Low dose CT lung screening for lung cancer showed an incidental finding of a liver lesion suggestive of neoplasm. Abdominal examination was unremarkable. CT abdomen and pelvis showed a 9 cm cystic and solid liver lesion in segment 5 associated with gallbladder fossa. The gallbladder was large, and hydropic, with an irregular wall, consistent with intrahepatic rupture of the gallbladder. Blood cultures were negative with no organisms seen on the gram stain, and no growth on the anaerobic culture as well. CT was concerning for cholangiocarcinoma associated with the gallbladder or could be intrahepatic rupture of the gallbladder. Ultrasound-guided Biopsy of the lesion showed needle core fragments of liver parenchyma with granulation tissue with cholestatic pigment associated with foreign body giant cell reaction. Rare foci of necrosis were present. The adjacent hepatocytes showed reactive changes. The overall findings were consistent with intrahepatic biloma. A Cholecystostomy tube was placed to drain the biloma. Repeat CT showed persistent intrahepatic biloma with slightly reduced size. A pigtail catheter was placed to drain the biloma. Discussion Spontaneous bilomas are a rare entity caused by bile leaks that are encapsulated either inside or outside of the liver without cause. Most often, they are secondary to iatragenic or traumatic causes. The common manifestations of biloma are abdominal pain, jaundice, fever, and leukocytosis, none were found in our patient. Appropriate diagnostic imaging includes Ultrasound, HIDA, CT, or even MR imaging. Differential diagnoses include bilhemia, angioma, abscess, cystic lesions, lymphocele, seroma, or hematomas, which can be differentiated with fluid studies. Complications such as infection, perforation, and impingement on surrounding structures may arise. Radiological image-guided aspiration gives us a definitive diagnosis, fluid studies help rule out the infection. Smaller bilomas less than 4 cm may resolve. Treatment of choice may include minimally invasive techniques such as percutaneous drainage or endoscopic retrograde cholangiopancreatography with appropriate stent placement and surgical removal for those that are refractory to treatment.