4v14 0012 Mp 78 Tuesday Nov 24 01:09 PM SV-Ab Image (v. 23, #6) 0012 (1595) Abdom Imaging 24:78-81 (1999) Abdominal I maging  Springer-Verlag New York Inc. 1999 Peritoneal serous papillary carcinoma: radiological appearance T. Furukawa, 1 J. Ueda, 1 S. Takahashi, 1 * K. Higashino, 1 K. Shimura, 2 T. Tsujimura, 3 Y. Araki 4 1 Department of Radiology, Sumitomo Hospital, 5-2-2 Nakanoshima, Kita-ku, Osaka 530-0005, Japan 2 Department of Gynecology and Obstetrics, Sumitomo Hospital, 5-2-2 Nakanoshima, Kita-ku, Osaka 530-0005, Japan 3 Department of Pathology, Sumitomo Hospital, 5-2-2 Nakanoshima, Kita-ku, Osaka 530-0005, Japan 4 Department of Radiology, Kinki University School of Medicine, 377-2, Ohno-higashi, Osaka-Sayama 589-0014, Japan Received: 12 November 1997/Accepted: 31 December 1997 Abstract Background: The radiological appearance of peritoneal serous papillary carcinoma (PSPC) is described. Methods: Three cases of PSPC were analyzed retro- spectively with regard to the radiological appearance and histopathological features. Results: All three patients were women, aged 44–71 years. Massive ascites and a greater omentum tumor were observed on computed tomography in all patients. Double-contrast enema performed in one patient showed irregularity on the upper aspect of the transverse colon. Radiological examinations excluded primary tu- mors in both gastrointestinal and genital organs in all patients. Histological diagnosis was made from the sur- gical specimen in two patients and from an autopsy specimen in one patient. All patients had a large omental tumor involving the transverse colon, but the ovaries were not involved or only minimally involved on the surface. Serum CA125 was markedly elevated, and im- munohistochemical staining for CA125 was positive within the tumor cell cytoplasm in all three patients. Conclusion: PSPC cannot be diagnosed from radiolog- ical findings alone because of its similarity to metastatic peritoneal carcinomatosis and peritoneal mesothelioma. Marked elevation of serum CA125 may help with PSPC diagnosis. Response to treatment is promising, and ex- ploratory laparotomy is thus justified when a patient shows characteristic radiological findings and high CA125 level. Key words: Peritoneum — Neoplasm — Computed to- mography—Barium enema—CA125. * Present address: Department of Radiology, Osaka University Med- ical School, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan Correspondence to: T. Furukawa Since 1959, when Swerdlow reported the first case of peritoneal serous papillary carcinoma (PSPC) as a ‘‘mesothelioma resembling papillary ovarian adenocar- cinoma’’ [1], PSPC has become recognized as an in- dependent pathological entity. The etiology of PSPC is uncertain but it is believed to be a primary peritoneal tumor arising from the secondary Mu ¨llerian system in the mesothelium. The histopathological features of this tumor are identical to those of ovarian papillary serous carcinoma (OPSC), but in PSPC the ovaries are intact or only their surface is affected [2]. The clinical features of PSPC are also similar to those of peritoneal carci- nomatosis due to OPSC and the response to using cis- platin-based chemotherapy regimen is favorable. Thus, a correct diagnosis of PSPC, distinguishing it from the other peritoneal malignancies with a poor prognosis, is required before treatment. There are few descriptions of the radiological appearance of PSPC in the literature; therefore, we analyzed the radiological, clinical, and histopathological features of this carcinoma in our in- stitution. Case reports Case 1 A 59-year-old woman presented with rapidly progressing abdominal distention and loss of appetite. She had a history of chronic thyroiditis for 25 years, but the thyroid function had normalized during that pe- riod. Physical examination showed diffuse goiter, massive ascites, and palpable induration in the lower abdomen. Cytological examination of ascitic fluid showed adenocarcinoma cells, which did not stain with periodic acid – Schiff with diastase digestion. Serum carbohydrate an- tigen 12-5 (CA125) was markedly elevated to 11,100 IU/mL (normal õ 35 IU/mL). Computed tomography (CT) demonstrated a poorly demarcated smudgy tumor in front of the transverse colon (Fig. 1A), but no involvement of the genital organs was observed. Double-con- trast enema showed irregularity on the upper aspect of the transverse