Malignant Primary Peritoneal Mesothelioma

PRESENTATION Vague symptoms belied a 59-year-old woman’s dire situation. She presented with a 3-month history of abdominal pain, constipation, and anorexia, accompanied by a 40- pound (18.1 kg) weight loss. Initially she had attempted to manage her symptoms conservatively, but worsening abdominal pain, bloating, and loss of appetite prompted her to seek medical care. The patient denied fevers, chills, nausea, vomiting, or blood in her stools. Ten years earlier she had undergone total hysterectomy with bilateral oophorectomy for significant endometriosis. Her medical history also included hypertension and migraines. She was a veteran and retired journalist who lived alone, had never smoked, and had not used alcohol or illicit drugs to any significant extent. ASSESSMENT On examination, the patient appeared fatigued but was alert and conversant. She was afebrile with blood pressure of 132/78 mm Hg, a heart rate of 107 beats per minute, a respiratory rate of 16 breaths per minute, and an oxygen saturation of 98% on room air. Her mucous membranes were dry, and a cardiac examination revealed regularrhythm tachycardia without murmurs, rubs, or gallops. Her abdomen was soft with normal bowel sounds, mild tenderness to palpation in the epigastria and right upper quadrant, and a noticeable mass in the right middle quadrant. Initial laboratory results were consistent with dehydration but otherwise unremarkable. Computerized tomography (CT) of the abdomen demonstrated infiltrative opacities of the omentum, several liver surface implants, and a very distended gallbladder (Figure 1A). Findings were concerning for peritoneal carcinomatosis. The initial differential diagnosis included metastasis of colon or gallbladder malignancy and gastrointestinal lymphoma. An ovarian cause was unlikely, given her surgical history. Lesion distribution made an upper gastrointestinal malignancy less likely, and a normal pancreas and kidneys ruled these out as locations for primary tumors. The patient’s hospital course focused on symptom management and attempts at obtaining a tissue diagnosis. A small amount of ascites was present but was both difficult to obtain and thought to be a low-yield source for a definitive diagnosis. None of the lesions seen on the initial CT scan appeared to be safe for biopsy. Consultation with the general surgery department resulted in a recommendation against a laparoscopic approach, because the patient’s low functional status raised concerns for complications and a potential treatment delay. Colonoscopy was considered, but she could not tolerate the bowel preparation due to ileus. Putative cancer biomarkers were measured as follows: carcinoembryonic antigen, 4 ng/mL (within normal limits); carbohydrate antigen 19-9, <3 U/mL (within normal limits); and carbohydrate antigen 125, 464 U/mL, which was elevated but nonspecific owing to her gynecologic history.1 Her symptoms worsened, and a repeat CT scan was obtained to rule out intestinal obstruction. A more accessible liver lesion was identified (Figure 1B), and she was scheduled for image-guided biopsy but became signifi- cantly somnolent after receiving a low-dose benzodiazepine. The procedure was not done; subsequently, she developed hypoxemic respiratory failure requiring intubation and mechanical ventilation. Given the patient’s metastatic disease and poor prognosis, she was transitioned to comfort measures and subsequently died