Mucinous Cystic Neoplasm of the Liver

Mucinous cystic neoplasm of the liver is a cystic epithelial tumour that produces mucin and has a characteristic ovarian type stroma. It replaces the older terms biliary cystadenoma and cystadenocarcinoma.

It occurs almost only in women, with a mean age of about 45 years, and is rare (under 5% of liver cysts of biliary origin). Most are solitary and large, in the right lobe or the left lobe, and multilocular with septations and mural nodules.

It has malignant potential: invasive carcinoma is found in about 5% to 30%, higher in older patients and in lesions with solid components or nodules.

Pathophysiology.

Epithelium secreting mucin lines the cyst and sits on cellular ovarian type stroma that expresses oestrogen and progesterone receptors. Progression from low grade to high grade dysplasia and carcinoma occurs.

Abdominal pain or discomfort, a palpable mass, early satiety, nausea and, less often, jaundice from compression or fever from infection. Rupture and haemorrhage are rare. Many cases are discovered incidentally.

Red flags.

• Mural nodules or thick septa.
• Rapid enlargement.
• Weight loss, jaundice or raised tumour markers.

Ultrasound, CT and magnetic resonance imaging show a large, multiloculated cyst with internal septa and sometimes calcification or mural nodules, with enhancement of septa and nodules. Serum CA 19-9 and carcinoembryonic antigen may be raised and are higher in malignancy. Aspiration, fine needle sampling and biopsy are avoided because of the risk of tumour spread and recurrence. Hydatid serology excludes echinococcal cyst.

Differential diagnosis.

• Simple hepatic cyst.
• Hydatid cyst.
• Haemorrhagic or infected cyst.
• Liver abscess.
• Cystic metastasis.
• Intraductal papillary neoplasm of the bile duct.

Complete surgical excision with clear margins (enucleation for benign lesions away from vessels, or hepatectomy for larger, deep or suspicious lesions) is the treatment. Do not aspirate, drain, sclerose or marsupialise, because recurrence is near universal. Resect invasive carcinoma with oncological margins and lymph node assessment.

• Cefazolin (surgical prophylaxis): 2 g IV (3 g if over 120 kg) within 60 minutes before incision; single dose, repeated after 4 hours if surgery continues; maximum 6 g in 24 hours for prophylaxis; monitor for hypersensitivity; adjust the interval when creatinine clearance is under 35 mL/min.

Adjuvant chemotherapy for invasive carcinoma (capecitabine 1,250 mg/m2 orally twice daily on days 1 to 14 of a 21-day cycle for 8 cycles) is a specialist decision.

Monitoring. Imaging and tumour markers at 6 to 12 months for 2 years, then yearly for 5 years.

Referral and escalation. Hepatobiliary surgery and oncology.