대한병리학회지: 제 37 권 제 1 호 2003
The Korean Journal of Pathology. 2003; 37: 74-7
Localized Malignant Mesothelioma of Peritoneum Arising in the
- A Case Report -
Hae Joung Sul∙Dae Young Kang Mesothelioma originates in several sites including the pleura, peritoneum, pericardium, and
tunica vaginalis. The pleura is the most common site of origin, but cases originating in the per-
Department of Pathology, Chungnam itoneum is relatively rare. Mesothelial lesions of the peritoneum may pose significant diagnos-
University College of Medicine, tic problems. Yet, the accurate identification of this lesion is important because of its distinctive
Daejeon, Korea behavior and treatment modality. We herein report a case of malignant mesothelioma of the
peritoneum arising in the capsule of the liver. The accuracy of our diagnosis has been confirmed
Received : October18, 2002 by the immunohistochemical study and electron microscopic examination.
Accepted : January 22, 2002
Hae Joung Sul, M.D.
Department of Pathology, Chungnam University
College of Medicine, 640 Daesadong, Jung-gu,
Daejeon 301-131, Korea
E-mail: email@example.com Key Words : Mesothelioma-Peritoneum
Peritoneal mesothelioma is a rare neoplasm and accounts for mesothelioma was made, and the mass was removed. Grossly, the
about 10% of all mesotheliomas.1 Malignant mesothelioma of tumor was adherent to the liver and consisted of variably sized
the peritoneum must be distinguished from the more common nodules (Fig. 1). Histologically, the tumor consisted of two cell
primary peritoneal serous epithelial neoplasms. This report doc- types: solid and papillary epithelial growth. In the papillary area,
uments a malignant tumor of the peritoneum that showed ultra- the papillary fragments consisted of two-cell thick layers of me-
structural and immunohistochemical features consistent with sothelial cells surrounding thin fibrovascular cores (Fig. 2A). In
malignant mesothelioma. the solid area, the tumor cells were arranged in cohesive groups
or sheets. The tumor cells had round or ovoid nuclei in variable
size with prominent nucleoli (Fig. 2B). Mitotic figures were less
CASE REPORT than 1/10 HPF. The tumor cells were diffusely positive for cal-
retinin (1:50, Zymed, San Francisco, U.S.A.) (Fig. 3A) and cytok-
A 55-year-old female patient presented with malaise, abdom- eratin (1:50, DAKO, Glostrup, Denmark), while negative for
inal pain, fever, and ascites. She also lost approximately 6 kg dur- carcinoembryonic antigen (CEA) (1:50, DAKO, Glostrup, Den-
ing the previous three months. She had no history of any other ill- mark) (Fig. 3B) and factor VIII related antigen (1:100, Zymed,
nesses preceding the onset of these symptoms. The patient had San Francisco, U.S.A.). Scanning and transmission electron mi-
no history of asbestos exposure. An ultrasonography and a com- croscopic examinations using paraffin blocks of the tumor tis-
puted tomography confirmed ascites as well as an ill-defined sue showed numerous long microvilli of the tumor cell surfaces
exophytic mass of the liver capsule. The cytologic examination (Fig. 4). The morphological findings were consistent with local-
of the ascites showed mostly red blood cells with only a few de- ized malignant mesothelioma. After the tumor excision, the pa-
generated mesothelial cells and inflammatory cells. The fine nee- tient was treated with Taxol by intraperitoneal injection. The
dle aspiration of the mass revealed mesenchymal elements and patient has been free of abnormal symptoms of the tumor for
spindle-shaped epithelial-like cells. A presumptive diagnosis of three months.
Localized Malignant Mesothelioma 2
DISCUSSION occur in individuals past 40 years of age, but the tumor has been
described in young adults,2 children,3 and neonates.4 The obser-
Mesotheliomas are located superficially in the body cavities. vation that patients with mesotheliomas are prone to develop
The pleural malignant mesothelioma is by far more common pleural effusion or ascites leads to the suggestion that cytologic
(about ten- to thirty-fold) than the peritoneal variants.1 Not in- examinations of effusion specimens would be useful in establish-
frequently, mesothelioms involve both the pleura and the peri- ing the diagnosis.5 However, not all patients with mesotheliomas
toneum as the result of direct extension through the diaphragm. have developed pleural effusion or ascites at the time of clinical
They very rarely occur in other locations (e.g., the pericardium presentation, and there are also cases of mesothelioma with neg-
and the tunica vaginalis). Most cases of peritoneal mesothelioma ative results in effusion cytology. Occasionally, the disease may
first manifestat itself in a hernial sac or in the umbilicus.6 In other
instances ing- uinal or cervical lymphadenopathy resulting from
a metastatic disease was the first sign of the tumor.7
Immunocytochemically, malignant mesothelioma cells are stro-
ngly positive for keratin, epithelial membrane antigen, basement
membrane-related proteins (type 4 collagen, laminin, and laminin
receptors), and calretinin; and they are generally negative for CEA,
B72.3, and Leu-M1.8 The tumor cells may also exhibit positiv-
ity for vimentin and, occasionally also, for actin and desmin.9,10
Some malignant mesotheliomas also express bcl-2 protein. A
recent study demonstrated that Leu-M1 was detected in 94% of
adenocarcinomas of the lung and in 58% of adenocarcinomas of
other organs but in none of 28 mesotheliomas.11 Thus, anti-Leu-
M1 may be of value in differentiating between adenocarcinoma
and mesothlioma of the peritoneum.
The differential diagnosis of a variety of mesothelial lesions of
the peritoneum includes mesothelial hyperplasia, multilocular
Fig. 1. The exophytic tumor is adherent to the liver surface (arrow). peritoneal inclusion cysts (benign cystic mesothelioma), well-dif-
Fig. 2. (A) Papillary structures with thin fibrovascular cores are surrounded by malignant mesothelial cells. (B) Solid sheets of the tumor
cells have eosino philic cytoplasm and vesicular nuclei with prominent nucleoli.
3 Hae Joung Sul∙Dae Young Kang
Fig. 3. (A) The tumor cells are diffusely immmunostained for calretinin. (B) Immunohistochemical staining for carcinoembryonic antigen is
completely negative in the tumor cells.
Fig. 4. Scanning (A) and transmission (B) electron micrographic views of the tumor cells show the intercellular spaces with multiple slen-
der microvilli (arrow) and desmosome (empty arrows).
ferentiated papillary mesothelioma, and diffuse malignant meso- is important for proper treatment. For undifferentiated tumors
thelioma. These lesions are usually different. The presence of many involving the pleura or peritoneum, the main diagnostic consid-
three-dimensional groupings of neoplastic cells with prominent erations are malignant mesothelioma and peritoneal serous epithe-
nucleoli, nuclear pleomorphism, and cell clusters in irregular ar- lial neoplasm (primary or metastatic). Unlike mesotheliomas, se-
rangements as in this case was not consistent with mesothelial rosal carcinomas do not show a diffuse and/or perinuclear distri-
hyperplasia. The distinction between malignant mesothelioma bution of tonofilaments.12,13 The long, thin, branching microvil-
and other malignant neoplasms diffusely involving the peritoneum li of relatively well differentiated mesotheliomas are often lost in
Localized Malignant Mesothelioma 4
poorly differentiated mesotheliomas.14 In these poorly differen- 5. Triol JH, Coston AS, Chandler SV. Malignant mesothelioma. Cyto-
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sothelial differentiation. These tumor cells showed characteristi- nod-
6. Chen KT. Malignant mesothelioma presenting as Sister Joseph’
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late stage of the disease. There is still no effective mode of ther- lioma and pulmonary adenocarcinoma: an immunohistological anal-
apy, but multiagent chemotherapy and radiation therapy, in addi- ysis demonstrating the value of Leu-M1 antigen. Am J Pathol 1986;
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