Gallium Scanning in Peritoneal Mesothelioma
Renato R. Armas1’2 Stanley J. Goldsmith1
Gallium scans in seven cases of pathologically proven primary pentoneal mesothelioma were reviewed and correlated with clinical, radiologic, and surgical findings. Although five patients gave a history of asbestos exposure, only two showed chest film findings typical of asbestosis. Most had abdominal discomfort, ascites, and abdominal
masses. Five of the seven had positive gallium scans; three showed a large single focus
of uptake and two showed diffuse abdominal uptake. Although these patterns correspend to the two main gross pathologic types described in peritoneal mesothelioma, there was not complete agreement with clinical, radiographic, and surgical findings, and the focal pattern tended to underestimate the extent of the disease. Although gallium uptake can be seen in a variety of other neoplastic and inflammatory conditions, it may be useful in the diagnosis and follow-up of peritoneal mesothelioma.
Peritoneal mesothelioma is a rare tumor, with an estimated incidence of less than 1/million/year in the United States [1 2]. Gallium scintigraphy has been reported to be sensitive in the detection of pleural mesothelioma , but only one case of a positive gallium scan has been reported in peritoneal mesothelioma . We describe our experience with gallium scintigraphy in a small group of patients with histologically proven malignant peritoneal mesothelioma.
Records of the tumor registry and Nuclear Medicine Department were reviewed, and all patients with proven primary malignant pentoneal mesothelioma who underwent gallium scanning were identified. Between 1 975 and 1982, 1 2 patients with peritoneal mesothelioma
seven of these had gallium scans, performed
In two patients, One patient the initial diagnosis with known pleural
as part of the initial diagnostic
were performed at
and treatment mesothelioma
and the gallium scan was obtained
at 2 and 3 years, respectively,
March 19, 1984; 24, 1984.
developed peritoneal involvement was excluded. The age range of patients was 33-63 years (mean, 49); there were five men and two women. Five gave a history of exposure to asbestos. All had symptoms of weight loss, abdominal distension, and/or pain. Ascites was noted in six of the seven, and in four patients one or more discrete masses were palpated. The diagnosis was confirmed at laparotomy in six, and by laparoscopy and peritoneal biopsy in the other. Three patients died 2-4 months after the gallium scan; the rest were lost to follow-up after periods of 6 months to a year.
Gallium scans were performed citrate, with more delayed views 48 hr after injection of 3-5 mCi (1 1 1 -1 85 MBq) of 67Ga after a Fleet enema if needed to differentiate normal bowel activity from pathologic uptake. Anterior and posterior views were obtained with (1) a Cleon 760 whole-body imager with a single 80-420 keV window at an information density of 500 counts/cm2 over the liver, or (2) a GE Maxicamera with a medium-energy collimator and
Andre Meyer Medicine, Mount
Department of Physics-Nuclear Sinai Medical Center, One Gus-
tave L. Levy P1., New York, NY 10029. Address reprint requests to S. J. Goldsmith. 2Present address: Interfaith Medical Center,
144:563-565, March 1985 0361 -803X/85/1 443-0563 C American Roentgen Ray Society
separate 20% windows centered on each of the 93, 188, and 296 keV photopeaks for a time equivalent to 800,000 counts over the abdomen. The patients’ clinical records and gallium scans were reviewed and correlated with the
clinical, radiologic, and operative findings.
Fig. 1 -48-hr gallium scan on whole-body scanner. Liver (solid arrowhead) medially displaced by ascites. Peritoneal mesothelioma is large focal area of accumulation (open arrowhead) inferior and to right of liver. Fig. 2-48-hr gamma camera views of anterior upper and lower abdomen. Diffuse, irregular uptake throughout abdomen.
were also detected by these methods. In the third, the leftupper-quadrant mass was only vaguely identified on physical examination and was not detected by sonography, but involvement of the spleen, adjacent left colon, stomach, and small bowel was found at surgery. In two of these three patients, therefore, the gallium scan underestimated the extent of disease. On the other hand, both patients with diffuse abdominal gallium uptake had diffuse involvement by clinical, sonographic, and/or surgical findings. Of the two patients with a negative gallium scan, one had been diagnosed 2 years before the examination and had received several courses of chemo- and radiotherapy, including intraperitoneal 32P, with good initial response. At the time of the gallium scan 1 year later, this patient had developed progressive ascites. He had multiple 4-5 cm masses on physical examination, and sonography showed diffuse pentoneal thickening. The other patient had been diagnosed at another hospital 4 months earlier, but had not received any chemo- or radiotherapy. Involvement of the liver, pancreas, omentum, and penitoneum was found at laparotomy at the time of diagnosis.
Results Of the five patients who gave a history of exposure to asbestos, only two showed typical chest radiographic changes of asbestosis (bibasilar fibrosis in one, and pleural thickening and calcification in another); a third had a pleural effusion. The rest had normal chest films. Five of the seven patients had abnormal gallium scans. In three, there was a large focal area of increased uptake in the left upper quadrant in two cases and in the epigastrium in the third (fig. 1). The other two patients showed diffuse, irregular uptake throughout the abdominal cavity (fig. 2). In two of the seven, the scan was entirely normal. Overall, there was no complete agreement as to the extent of disease among clinical findings, gallium scan, radiologic procedures, and surgery; instead, the various findings tended to complement each other. Of the three cases where gallium showed a localized mass, one was confirmed by barium enema and sonography, but diffuse nodular involvement of the peritoneum was found at laparotomy. In another (fig. 1), the large epigastric mass was confirmed by physical examination and sonography, but multiple additional smaller masses
Discussion The clinical diagnosis of penitoneal mesothelioma is difficult. Symptoms and signs at presentation are varied and nonspecific [2, 5], and a history of asbestos exposure may often be absent [1 1. Radiographic changes may be striking, but are also nonspecific; only a minority show changes of asbestosis on chest radiography . Sonography and CT findings have also been described . Laparotomy is usually required for diagnosis. Pathologically, two main types of penitoneal mesothelioma have been described: In one, a large mass predominates, with smaller nodules scattered around in the peritoneum; in the other, nodules and plaques are scattered throughout the abdomen . These correspond to the two gallium-scan uptake patterns observed in our patients. The gallium patterns are also nonspecific. The localized form must be differentiated from focal inflammatory lesions and other abdominal malignancies, including lymphoma and gastrointestinal and genitourinary tumors . The differential diagnosis of the diffuse pattern includes peritonitis, both infectious [9, 10] and inflammatory [1 1 ], and other diffuse malignancies, such as Burkitt lymphoma . In contrast to pleural mesothelioma , it seems that the focal pattern underestimates the extent of disease. Of the two false-negative cases, only one could be explained by his having received extensive therapy before the scan. Whether gallium can be useful in the assessment of response to therapy and determination of prognosis, as demonstrated in other malignancies , cannot be assessed in our small series. In conclusion, although in this small series gallium was positive in most patients with peritoneal mesothelioma, its use in diagnosis and staging of the disease is limited by its nonspecificity and the tendency of the focal pattern to underestimate the extent of involvement. The disease should be
included in the differential abdominal gallium uptake, tory of asbestos exposure.
of focal in patients
and diffuse with a his-
1 . Brenner J, Sordillo PP, Magill GB, Golbey RB. Malignant perito-
7. 8. 9. 10.
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