A CASE OF BENIGN MULTICYSTIC MESOTHELIOMA OF THE RETROPERITONEUM

Abstract

A case of benign multicystic mesothelioma is presented. A 41-year-old woman was seen at the hospital because of right lower abdominal pain. A tumor in the right lower quadrant was palpated. Abdominal CT revealed a huge multilocular cystic tumor covering from the subhepatic space to pelvic cavity. The patient was operated on. On gross examination, the cysts measured 17cm in diameter, and weighed 800g, were multilocular and thin-walled, and contained clear and serous fluid. On microscopic examination, the cyst wall was lined by a single layer of cuboidal to columnar cells accompanied by some hobnial-shaped cells, and no evidence of malignancy was found. Immunohistochemical staining has revealed cystoplasmic positivity within the mesothelial cells using antibodies to cytokeratin and vimentin, in addition to negative staining for Factor VIII. Most mesotheliomas of the retroperitoneum are diffuse and malignant, and localized and benign mesotheliomas are rare. Among these benign mesotheliomas of the retroperitoneum, multicystic type is specific and 25% of these mesotheliomas recur even after histologically diagnosed benign and demand a follow-up observation.