Successful Management of a 27-cm Mucinous Cystic Neoplasm of the Liver With Laparoscopic Excision: A Case Report

Mucinous cystic neoplasms of the liver (MCN-L) are rare cystic tumors defined by the presence of ovarian-type subepithelial stroma beneath mucin-secreting epithelium and carry a risk of malignant transformation, necessitating complete surgical excision. Giant MCN-L lesions are exceptionally uncommon, and data regarding minimally invasive management of such large tumors remain limited. A 44-year-old woman (American Society of Anesthesiologists I) presented with a six-month history of progressive right-sided abdominal fullness. Contrast-enhanced computed tomography revealed a large 27 × 18 × 19 cm thin-walled, unilocular cystic lesion arising from the posterior segments of the right hepatic lobe, extending into the pelvis. Laboratory investigations demonstrated microcytic hypochromic anemia (hemoglobin 9.6 g/dL), with preserved liver and renal function. Serum tumor markers showed carcinoembryonic antigen of 0.70 ng/mL, carbohydrate antigen 19-9 of 11.33 U/mL, cancer antigen-125 of 13.3 U/mL, and alpha-fetoprotein of 9.27 ng/mL. Hydatid serology was negative. The patient underwent laparoscopic right posterior sectionectomy (segments VI and VII) with cholecystectomy. Approximately 4.5 L of clear fluid was aspirated in a controlled manner to decompress the cyst and improve operative exposure. Complete excision of the cyst-replaced posterior sector was achieved. The operative time was approximately 210 minutes with an estimated blood loss of 150 mL. Histopathological examination confirmed mucinous cystic neoplasm with mucin-secreting epithelium (cytokeratin 7 positive, cytokeratin 20 negative) and characteristic ovarian-type stroma expressing estrogen and progesterone receptors, without dysplasia or malignancy. The postoperative course was uneventful, and the patient was discharged in stable condition. At one-year follow-up, there was no evidence of recurrence. This case highlights that laparoscopic right posterior sectionectomy is feasible for giant MCN-L, even when the lesion exceeds 25 cm, provided careful decompression and appropriate surgical expertise are available. At 27 cm, this represents one of the largest MCN-L successfully managed using a purely laparoscopic approach. Complete excision remains essential due to the malignant potential of these lesions.