Benign cystic mesothelioma (BCM) is a rare tumor with benign characteristic. It was first described in 1979 by Mennemeyer and Smith (1). About 141 cases of BCM have been reported, but only 8 cases in children have been found (1). Here we present a 2-year old boy with BCM originating from the liver.
Benign cystic mesothelioma is a rare abdominal tumours among women in the reproductive age. Various alternative names have been proposed, including inflammatory inclusion cyst of the peritoneum, multilocular peritoneal inclusion cysts, benign cystic mesothelioma and multicystic mesothelial proliferation (2). Generally it originates in the pelvic retro peritoneum and may also originate in serosa of the pelvic viscera. From this site the BMC can spread to the visceral peritoneum of pelvic and abdominal organs including uterus, kidney, bladder, liver, and colon (2). In addition, extra-abdominal localized cases such as chest and pericardium have been reported (3, 4). The most common cause of admission to hospital is pelvic and lower abdominal pain. Palpable mass can be determined in some cases, but occasionally the lesions can be incidentally encountered at during laparotomy. A rare cause of ascites in children should be kept in mind (5). The etiology of BCM is controversial but is probably either neoplastic or else reactive because of a strong correlation in women with pelvic inflammatory disease (6). Patients who have been diagnosed Familial Mediterranean Fever have developed BCM or malignant mesothelioma subsequently (6). BCM has been suggested that may be a variant between benign and malignant mesothelioma (5). Exposure to asbestos does not consider as a factor in BCM development. The lack of asbestos exposure in the patient’s story supports non-neoplastic nature of our patient. Progression to malignancy is rare but in literature nevertheless it has been reported in 2 cases (6). The probability of BCM’ s recurrence can go up to 75% and has occurred in an early period such as 1 month or in a late period as 16 years later (case reports in the literature) (7). Benign cystic mesothelioma’s preoperative diagnosis is difficult because of the nonspecific imaging. Cellular analysis of peritoneal washings can be useful for diagnosis in preoperative period in recent studies but it is not specific because reactive mesothelial cells are also seen in viral infections, cirrhosis and connective tissue disorders (8). Differentiation of BCM from other cystic lesions such as cystic lymphangioma and malignant mesothelioma, is made with the combination of cytology of the peritoneal washing including abundant mesothelial cells, histology and clinical story (9). In our case, definitive diagnosis was confirmed by histopathological examination of the surgical specimen. Immunohistochemical studies revealed multiple cysts lined by mesothelial cells and there was strong cytoplasmic immunoreactivity for calretinin in cells lining the cysts.
En block removal of BCM via laparotomy or laparoscopy is the most commonly reported management technique as we used in our patient. However, different treatment methods are used in adult patients, such as hormonal managements, USG or CT-guided aspiration, image-guided sclerotherapy, potassium-titanyl-phosphate laser ablation and chemotherapy (8). A variety of sclerosing agents such as povidone-iodine, ethanol, doxycycline or tetracycline may also be used. Lim et al. used sclerotherapy for the treatment of 29 patients with BCM (peritoneal inclusion cyst). They used povidone-iodine and ethanol. Long term success rate was 90 % and there was no significant difference in the success rate between the use of povidone-iodine and ethanol (10).
Despite the variety of treatment options, there is no absolute consensus on treatment because of the underlying pathogenesis, long-term results and complications rates are unknown. Contrary to our case en block removal of the mesothelioma is often not possible, recurrence is frequent and malignant degeneration has been reported, thus accurate diagnosis requires histological evaluation of a specimen.
BCM should be kept in mind a rare cause of the abdominal mass in children. Because it may lead to confusion preoperative diagnosis. Although rare, patients should be followed for life long because of the risk of recurrence and malignant degeneration.
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