Medical and Pediatric Oncology 31:123–124 (1998) BRIEF REPORT Long-Term Follow-Up of a Well-Differentiated Mesothelioma of the Peritoneum in a 2-Year-Old Girl The unusual clinical course of a girl with welldifferentiated mesothelioma is of interest. She was diagnosed at the age of 2 years and is living with the disease 9 years later. She was admitted with fever, abdominal swelling, and an inguinal hernia. Ascites was confirmed on ultrasound, but no mass lesion could be detected. Bloody ascites was aspirated and cells suggestive of mesothelioma were found. At laparotomy, the abdomen was filled with ascites and small cysts and nodules, which covered the liver, spleen, omentum, and peritoneum (Fig. 1). Omentectomy, an appendectomy, and a bilateral herniorrhaphy were performed, but complete resection was impossible. Pathologic examination showed mesothelial cells with epithelioid differentiation, arranged in papillary patterns. The cells were monomorphous with round or ovoid nuclei without atypia and few mitoses. Focal areas of calcification and psammoma bodies were present (Fig. 2). No asbestos particles could be observed. No hyperchromasia or anaplasia and no invasive growth was seen. Well-differentiated mesothelioma was diagnosed, but reactive mesothelial hyperplasia was also discussed. Because of uncertainty concerning the evolution of her disease, a decision for close observation was made. Two months later, ascites was again detected on ultrasound, 1 year after it was first detected. Treatment with furosemid and aldactone was started. After 2 weeks, prednisone (1 mg/kg/day) was added and the ascites disappeared for a short time. Alpha-interferon (3,000,000 U/m2 s.c.) was given 3 days/week for 9 weeks without measurable reduction of ascites or tumor, but then had to be stopped because of severe thrombocytopenia. A second operation was performed 4 years later, at the age of 6 years. Small nodules covered all surfaces of the parietal and visceral peritoneum. Complete removal was attempted by superficial resection. The histopathologic features were unchanged. The girl lived on for 4 years with visible disease on ultrasound. At the age of 10 years, she was readmitted with bowel obstruction. It was found to result from a cystic tumor that was firmly aherent to the stomach and transverse colon, making partial resection of these organs necessary. The diagnosis of welldifferentiated mesothelioma was confirmed. The girl is now 11 years old. Her height and weight are in the 3rd percentile. She suffers from recurrent attacks of abdominal pain and has visible residual disease on ultrasound. There are only a few case reports that deal with the treatment of well-differentiated mesothelioma in chil- Fig. 1. Intraoperative view of well-differentiated cystic mesothelioma. The arrowhead indicates a mesothelioma of the splenic capsule. © 1998 Wiley-Liss, Inc. 124 Fig. 2. ×15. Wünsch et al. Papillary differentiation and psammoma bodies are evident. Cells are monomorphous with ovoid nuclei; mitoses or atypia are absent. dren; surgery alone is mentioned [1–3]. Complete removal of diffuse mesothelioma can rarely be accomplished. Systemic chemotherapy has been considered in this case, but was thought probably to be ineffective because of the low malignancy of the lesions. Intraperitoneal chemotherapy has been used for peritoneal carcinomatosis and pseudomyxoma peritonea in adults, combined with adhesiolysis and removal of bulky tumor. Effective agents for mesothelioma are, however, unknown. Peritonectomy has also been combined with multivisceral resections and intraperitoneal chemotherapy in adults. Because the stomach, spleen, and colon must be sacrificed, this treatment is considered too aggressive in children. Prolonged symptomatic relief and improvement of somatic growth have been observed in our patient after incomplete tumor resection. Until effective systemic or intraperitoneal treatment regimens are developed, a lim- ited surgical approach as described here seems acceptable. L. Wünsch, MD P. Flemming, MD A. Reiter, MD Children’s Hospital and Division of Pathology Hannover Medical School D-30625 Hannover, Germany REFERENCES 1. McCullagh M, Keen C, Dykes E: Cystic mesothelioma of the peritoneum: A rare cause of ‘‘ascites’’ in children. J Pediatr Surg 29:1205–1220, 1994. 2. Hanucoglu A, Gewurtz G, Zaidel L, et al. Benign cystic mesothelioma of the peritoneum: The occurrence of an adult entity in a child. Med Pediatr Oncol 20:169–171, 1992. 3. Silberstein MJ, Lewis JE, Blair JD, et al.: Congenital peritoneal mesothelioma. J Pediatr Surg 18:243–246, 1983.