Can you Identify This Malignancy?

A Malignant peritoneal mesothelioma B Benign multicystic peritoneal mesothelioma C Well-differentiated papillary mesothelioma History Mr. B. is a 39-year-old male with no significant medical history who began experiencing progressive abdominal girth and bloating. Ultrasound and CT of the abdomen and pelvis revealed moderate to large abdominal ascites. Ultrasound-guided paracentesis yielded 7 L of serous fluid, with cytology showing atypical me-sothelial cells. Upper endoscopy and chest CT were unremarkable. Exploratory lapa-roscopy demonstrated a large amount of abdominal ascites and carcinomatosis involving the peritoneal surfaces, omentum, and surfaces of the left and right lobes of the liver. Biopsies of peritoneal surfaces and liver implants confirmed a diagnosis of mesothelioma, and Mr. B. was referred to surgical oncology. Mr. B. presents to the surgical oncology clinic with right upper quadrant pain extending to the right flank, 7/10 on the pain scale, exacerbated by lying on his right side. He has not been taking any pain medication. He reports abdominal bloating , progressive abdominal girth since paracentesis, early satiety, excessive gas with large meals, subjective weight gain, and dyspnea on exertion after climbing one flight of stairs. Mr. B. has never had a colonoscopy. He is a lifelong nonsmoker and denies any alcohol or drug use or any prior asbestos exposure to his knowledge. He works as a customer service representative at a department store and specifically denies any knowledge of occupational or recreational chemical exposure. Upon physical exam, Mr. B. is a healthy-appearing male of stated age, in no apparent distress. His vital signs are normal. Abdominal exam reveals a dome-shaped abdomen with gross ascites. Normoac-tive bowel sounds are present with no hepatosplenomegaly. Shifting dullness and fluid wave are noted. There is mild tenderness to deep palpation of the right mid-abdomen. No stigmata of cirrhosis, jaundice, scleral icterus, or lower extremity edema are noted. Cardiac exam is unre-markable. Laboratory analysis reveals Mr. B.'s CA-125 level to be 263.3 U/mL (normal range: 0–35 U/mL). His CEA and CA 19-9 levels are normal, as are his complete blood count, liver function tests, and kidney function. Cross-sectional imaging of the abdomen and pelvis (see Figure) show a large amount of ascitic fluid extending into the pelvis, with the omentum displaced and compressed by fluid as well as omental caking. No dominant mass is identified, and intra-abdominal and pelvic organs are unremarkable except for a hepatic cyst. Repeat ultrasound-guided paracentesis is performed for symptomatic relief, yielding 5 …