An autopsy case of peritoneal malignant mesothelioma in a radiation technologist

A case of peritoneal malignant mesothelioma in a radiation technologist, who had worked in this field for 34 years, is reported. Histopathologically, a biopsy specimen from the retroperitoneal tumor revealed a biphasic type of malignant mesothelioma. Electron microscopy disclosed that the tumor cells contained prominent microvilli, basal laminae adjacent to the stroma, junctional complexes, desmosomes, tonofilaments, clusters of glycogen granules, well developed rough endoplasmic reticulum (RER), confronting cisternae showing direct continuity with the RER and membrane-bound granules suggestive of secretory activity. No increased amount of asbestos was detected in autopsied lung material or the peritoneal mesothelioma. The estimated cumulative dose of occupational irradiation was calculated to be about 40 to 50 rad at most. Irradiation was discussed in relation to the etiology of the peritoneal mesothelioma.     

Two cases of malignant peritoneal mesothelioma without asbestos exposure: cytologic and immunohistochemical features

Approximately half a century has passed since asbestos was first reported to be the main cause of malignant mesothelioma; yet the incidence of this disease continues to increase worldwide. Twenty percent of cases occur without prior asbestos exposure, and in these patients, malignant peritoneal mesothelioma is more common than malignant pleural mesothelioma. Here, we report the cytomorphologic and immunohistochemical features of 2 cases of malignant peritoneal mesothelioma where there was no history of asbestos exposure. Ascitic cytology showed that most cells were isolated and that clusters were rarely observed, but the findings were consistent with malignant mesothelioma in both cases. Immunohistochemical analysis for epithelial membrane antigen, calretinin, vimentin, β-catenin, melan-A, glucose transporter-1, cytokeratin CAM5.2, Wilms tumor antigen-1, D2-40, CD146, progesterone receptor, estrogen receptor, and cytokeratin 5/6 was indicative of malignant mesothelioma. In malignant mesothelioma without prior asbestos exposure, the etiology and prognostic significance is still unclear. Further study is needed to clarify this point.     

Immunoelectron microscopic demonstration of glycoprotein subunits in the FSH producing pituitary adenomas

Immunoelectron microscopic observations disclosed the presence of FSH alpha, beta subunits in secretory granules and rough endoplasmic reticulum (RER). Golgi saccules were consistently negative. The presence of these subunits in secretory granules which were located in the vicinity of RER or perinuclear spaces (PNS) suggested the possible formation of secretory granules in RER or PNS. The tumor cells showed heterogeneity in size and immunoreactivity of the secretory granules but non-neoplastic cells showed uniformity in these aspects.     

Malignant mesothelioma of the peritoneum invading the liver and mimicking metastatic carcinoma: a case report

We present a case of malignant mesothelioma of the peritoneum with massive direct invasion to the liver in a 58-year-old Japanese woman. She had no history of asbestos exposure or other malignancies. Abdominal computed tomography revealed one 8-cm intrahepatic mass adjacent to the abdominal wall with peritoneal thickening, multiple smaller nodules in the peritoneal cavity, and intra-abdominal lymphadenopathy. Liver biopsy showed a small cluster of atypical cells similar to epithelial neoplasm, which formed a tubulopapillary structure. The tumor cells were positive for calretinin with strong nuclear and cytoplasmic expression together with podoplanin (D2-40) and some cytokeratins, but were negative for hepatocyte paraffin 1 and other adenocarcinoma markers. We confirmed a diffuse peritoneal mesothelioma with direct invasion to the liver. Liver masses with other peritoneal nodules are mostly encountered as metastatic diseases. However, the possibility of mesothelioma should be considered, even in women without an apparent history of asbestos exposure.     

Malignant peritoneal mesothelioma: Quantitative analysis of asbestos burden

Malignant mesotheliomas develop commonly in the pleural cavity and rarely arise in the peritoneal cavity. It is well established that asbestos exposure is related to malignant pleural mesothelioma, but the asbestos burden in the abdominal cavity in patients with malignant peritoneal mesothelioma has not been well studied. The purpose of the present study was therefore to report on an autopsy case of malignant peritoneal mesothelioma with quantitative analysis of the asbestos burden in tissues from the pleura and organs in the abdominal cavity. The patient was a 67-year-old man with a history of asbestos exposure. The peritoneum was thickened with diffuse tumor proliferation. This patient was diagnosed as having malignant peritoneal epithelioid mesothelioma. The number of asbestos fibers was >10 000/g dry tissue in all samples examined except in the small intestine. The number of asbestos fibers in the stomach was 53 000/g, which was higher than that in a control asbestosis subject. The existence of numerous asbestos fibers found in the abdominal cavity suggests that asbestos stimuli are related to the tumorigenesis of malignant peritoneal mesothelioma.     

Polycystic mesothelioma of the peritoneum. Description of 4 cases]

Cystic mesothelioma is a rare tumor of the peritoneal cavity arising from mesothelial cells. About 130 cases have been reported in the literature. The tumor is more frequent (85%) in adult women and rarely occurs in children. It is benign but recurrences are often described. The differential diagnosis with adenomatoid tumors, lymphangiomas, cystic malignant mesotheliomas and metastatic serous cystic tumors of the ovary is supported by immunohistochemistry. We describe four cases of cystic mesothelioma of the peritoneum; two of the cases occurred in pregnant women, one in a 45-year-old man and one in a 5-year-old boy. Asbestos exposure was not documented. The mesothelial origin of the neoplasms was supported by immunohistochemical analysis. Furthermore, tests for simian virus 40 (SV40 T antigen), to determine whether this virus was also present in the lesions, were negative.     

Malignant biphasic peritoneal mesothelioma in a child: Fine-needle aspiration cytology, Histopathology, and immunohistochemical features along with review of literature

Peritoneal mesotheliomas in children are of rare occurrance. We herein report the clinical, radiological, and pathological findings of a rare case of malignant peritoneal mesothelioma occurring in nine‐year‐old female child. The child presented with abdominal distension and awareness of a painless mass in the abdomen which on radiology appeared as a large heterogeneous pelvic mass with peritoneal deposits at multiple sites. To the best of our knowledge, this is the first case of a peritoneal malignant mesothelioma on which fine needle aspiration (FNA) was performed as first line investigation of the primary tumor. The cytological features, major differential diagnoses, and the pitfalls therein are discussed. Histopathology revealed biphasic pattern of mesothelioma which is again a rare pattern. Immunochemistry was carried out on the cell block made from the FNA as well as the biopsy specimen essentially showed the same features. There was positivity for vimentin, EMA, and cytokeratin 5/6 while WT1, calretinin, and CEA were negative; however, D2‐40 showed diffuse membranous positivity in the epithelial areas and cytoplasmic positivity in the spindle areas confirming a mesothelioma. We emphasize the use of immunochemistry on cell block material for a confident diagnosis of mesothelioma in such cases. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.     

The performance of expansile nanoparticles in a murine model of peritoneal carcinomatosis

Carcinomatosis from peritoneal surface malignancies, such as mesothelioma, appendiceal carcinoma or ovarian metastases, significantly decreases survival and quality of life. Given a 60-80% locoregional recurrence rate after surgical debulking for mesothelioma, the current study explores the use of polymeric nanoparticles, specifically engineered to expand and locally deliver chemotherapeutic agents at endosomal pH, for the prevention of progressive carcinomatosis. Anti-tumor efficacy of paclitaxel-loaded pH-responsive expansile nanoparticles (Pax-eNP) was evaluated in vitro and in in vivo murine models of malignant peritoneal mesothelioma. Pax-eNP inhibited mesothelioma growth in vitro, markedly decreased tumor growth and disease severity in vivo, prevented initial intraperitoneal tumor implants, and significantly prolonged survival compared to other intraperitoneal drug delivery methods. These outcomes suggest that the mechanism of pH-triggered drug delivery and tumor affinity associated with eNP may effectively improve the local control of residual microscopic disease following surgical debulking of locoregionally aggressive malignancies.     

ULTRASTRUCTURAL LOCALIZATION OF PROLACTIN IN THE HUMAN PITUITARY PROLACTINOMAS AND ITS CHANGES BY BROMOCRIPTINE TREATMENT

Fourteen human prolactinomas, four of which received bromocriptine treatment, were studied by immunoelectron microscopy to observe the intracellular localization of prolactin (PRL). In the untreated cases two different patterns of PRL localization were noted. In the first type (Type I) PRL was seen in Golgi saccules, single stacks of rough endoplasmlc retlculum (RER), and a few secretory granules and in the second type (Type II) it was present in the predominant parallel arrays of RER. Type II cells were observed more frequently in the cases with higher serum prolactin levels. In the treated cases with normalized serum prolactin levels, the tumor cells showed accumulation of secretory granules. This finding suggested secretory inhibition. RER and Golgi saccules were inconspicuous in these cells and this might indicate decreased production of PRL. In a case which was resistant to the bromocriptine treatment, most tumor cells were similar in ultrastructural localization of PRL to those cells in the untreated cases and this might suggest the lack of dopamine receptor.     

Ultrastructural localization of prolactin in the human pituitary prolactinomas and its changes by bromocriptine treatment

Fourteen human prolactinomas, four of which received bromocriptine treatment, were studied by immunoelectron microscopy to observe the intracellular localization of prolactin (PRL). In the untreated cases two different patterns of PRL localization were noted. In the first type (Type I) PRL was seen in Golgi saccules, single stacks of rough endoplasmic reticulum (RER), and a few secretory granules and in the second type (Type II) it was present in the predominant parallel arrays of RER. Type II cells were observed more frequently in the cases with higher serum prolactin levels. In the treated cases with normalized serum prolactin levels, the tumor cells showed accumulation of secretory granules. This finding suggested secretory inhibition. RER and Golgi saccules were inconspicuous in these cells and this might indicate decreased production of PRL. In a case which was resistant to the bromocriptine treatment, most tumor cells were similar in ultrastructural localization of PRL to those cells in the untreated cases and this might suggest the lack of dopamine receptor.     

Malignant peritoneal mesothelioma as a pelvic mass. Application of athymic mice in clinical pathology

We reported herein an unusual presentation of malignant peritoneal mesothelioma which appeared as a solid pelvic tumor in a 73-year-old man. The solid tumor was confined in the pelvic cavity, except for one tiny disseminated nodule on the mesocolon. The pelvic tumor was resected with whole pelvic organs en bloc. Histologically, the tumor consisted of tubular and sarcomatous structures, suggesting the biphasic malignant mesothelioma. One of the transplanted tumors in athymic mice was cystic and its histology had striking similarities to cystic mesothelioma. Transplantation of human neoplasms to athymic mice may be able to reproduce histological diversity of the tumor, even if it is not fully expressed in the original tumor.     

Mesothelioma. Histological and electron microscopic study of human cases

Four cases of mesothelioma were studied histologically and electron microscopically. One of them showed a pure epithelial type of the peritoneal origin, characterised by a tremendous production of hyaluronic acid. The other three tumors originated from the pleura revealed a histology of biphasic type mesothelioma, which showed an admixed tubular and fibrous pattern and consisted of small-sized cells with slight atypia. However, in some places of these tumors they showed considerable atypical features appearing like an anaplastic or squamoid carcinoma and/or spindle cell sarcoma. Hyaluronic acid was histologically demonstrated in the cytoplasmic vacuoles as well as in the luminal space surrounded by the tumor cells. Electron microscopically, varied numbers of microvilli and desmosome-like attachments were found on the surface of the tumor cells. Mitochondria were small and round. Well-developed rERs tended to encircle mitochondria and to dilate forming cisternae. Various amounts of microfilaments were found in the cytoplasm. The tumor cells which were rich in the latter two components, dilated rERs and microfilaments, resembled fibroblasts. Some tumor cells had phagosomes including dense and fine granules similar to ferritin, suggesting their phagocytotic activity. The hyaline matrix, common to the biphasic type tumor which was largely composed of dense collagenous tissues, was demonstrated to contain hyaluronic acid by histochemistry, and it was suggested that some secretory substances of the tumor cell may participate in composing the hyaline matrix to some extent.     

MALIGNANT PERITONEAL MESOTHELIOMA AS A PELVIC MASS

We reported herein an unusual presentation of malignant peritoneal mesothelioma which appeared as a solid pelvic tumor in a 73-year-old man. The solid tumor was confined in the pelvic cavity, except for one tiny disseminated nodule on the mesocolon. The pelvic tumor was resected with whole pelvic organs en bloc. Histologically, the tumor consisted of tubular and sarcomatous structures, suggesting the biphasic malignant mesothelioma. One of the transplanted tumors in athymic mice was cystic and its histology had striking similarities to cystic mesothelioma. Transplantation of human neoplasms to athymic mice may be able to reproduce histological diversity of the tumor, even if it is not fully expressed in the original tumor. ACTA PATHOL. JPN. 37:1149–1156, 1987.     

Histological and Electron Microscopic Study of Human Cases

Four autopsy cases of mesothelioma were studied histologically and electron microscopically. One of them showed a pure epithelial type of the peritoneal origin, characterised by a tremendous production of hyaluronic acid. The other three tumors originated from the pleura revealed a histology of biphasic type mesothelioma, which showed an admixed tubular and fibrous pattern and consisted of small-sized cells with slight atypia. However, in some places of these tumors they showed considerable atypical features appearing like an anaplastic or squamoid carcinoma and/or spindle cell sarcoma. Hyaluronic acid was histologically demonstrated in the cytoplasmic vacuoles as well as in the luminal space surrounded by the tumor cells. Electron microscopically, varied numbers of microvilli and desmosome-like attachments were found on the surface of the tumor cells. Mitochondria were small and round. Well-developed rERs tended to encircle mitochondria and to dilate forming cisternae. Various amounts of microfilaments were found in the cytoplasm. The tumor cells which were rich in the latter two components, dilated rERs and microfilaments, resembled fibroblasts. Some tumor cells had phagosomes including dense and fine granules similar to ferritin, suggesting their phagocytotic activity. The hyaline matrix, common to the biphasic type tumor which was largely composed of dense collagenous tissues, was demonstrated to contain hyaluronic acid by histochemistry, and it was suggested that some secretory substances of the tumor cell may participate in composing the hyaline matrix to some extent. ACTA PATHOL. JPN. 34: 1411–1424, 1984.     

Establishment and characterization of a new human mesothelioma cell line (T-85) from malignant peritoneal mesothelioma with remarkable thrombocytosis

A mesothelioma cell line, termed T-85, was established from a patient with malignant peritoneal mesothelioma and remarkable thrombocytosis (1.4 × 10⁶/mm³). Electron microscopically, two types of mesothelioma cells have been characterized; the major type of cells with dense-cored granules in the cytoplasm and the minor one with evenly dense granules. Immunologically, the cells showed staining for inter-leukin-6 (IL-6), cytokeratin, collagen type IV, vimentin, laminin, fibronectin and Factor VIII-related antigen. Quanti-tation by ELISA revealed a high concentration of IL-6 in T-85 cell culture supernatants. RT-polymerase chain reaction of T-85 cells showed two positive bands of cDNA at 628 and 251 base pairs indicating the constitutive expression of IL-6 and IL-6 receptor mRNA. Moreover, prominent pro-platelet process formation activity in T-85 cell culture supernatants indicated the presence of a thrombopoietic activity due mainly to IL-6 but not the c-MpI ligand or erythropoietin. However, the fact that 15% of PPF activity remained in the supernatants treated with anti-IL-6 antibody indicated the presence of another thrombopoietic substance. T-85 is so far the first mesothelioma cell line derived from a case with remarkable thrombocytosis.     

Localized malignant peritoneal mesothelioma containing rhabdoid cells

A case Is presented of localized malignant peritoneal mesothelioma appearing as a liver neoplasm. The patient underwent tumor resection but developed a recurrent growth and died 10 months after the Initial surgery. The primary tumor showed sarcomatous features with rhabdoid cells. Examination revealed the presence of hyaluronic acid, co-Immunoreactivlty for cytokeratln epithelial membrane antigen and vlmentln, cellular contacts with small desmosomes, and intracytoplasmic lumina. These findings supported the mesothelial nature of this tumor. The recurrent tumor was composed of predominantly tubulopaplllary proliferation. It was concluded that the present tumor was a localized malignant mesothelioma of a blphasic type showing a predominantly sarcomatous component in the primary tumor.     

Granulocyte-colony stimulating factor- and interleukin 6-producing diffuse deciduoid peritoneal mesothelioma.

An autopsy case of granulocyte colony-stimulating factor (G-CSF)- and interleukin-6 (IL-6)-producing diffuse deciduoid peritoneal mesothelioma is reported. The patient was a 70-year-old man with abdominal distension and weight loss in the year prior to his death. Laboratory data suggested severe inflammation with marked leukocytosis, thrombocytosis and elevated serum levels of C-reactive protein, G-CSF and IL-6. Imaging studies showed an expansive mass occupying the entire abdomen and pelvic cavity. Histological diagnosis of tissue taken by needle biopsy was difficult due to the unusual sarcomatoid-appearance of the tumor. In addition, there was severe infiltration of numerous neutrophilic leukocytes. An autopsy revealed that the diffuse peritoneal tumor had a fresh fishmeat-like appearance with focal mucinous degeneration and entirely encased the abdominal organs. Histological examination showed a sheet-like proliferation of tumor cells with large ovoid or polygonal cytoplasm, large atypical nuclei and obvious nucleoli. The tumor cells showed abundant glycogen and hyaluronic acid, and were immunoreactive to cytokeratin, calretinin, epithelial membrane antigen (EMA), CA-125, and focally to vimentin. The tumor cells were immunoreactive to G-CSF and IL-6. Electron microscopy revealed long, slender microvilli on the tumor cell surface. This tumor was diagnosed as a G-CSF- and IL-6-producing, diffuse deciduoid mesothelioma. We report this case with special reference to the differential diagnosis of deciduoid peritoneal mesothelioma with paraneoplastic syndrome.     

Malignant Peritoneal Mesothelioma With Massive Foamy Cells: Codfish Roe-Like Mesothelioma

An autopsy case of a 45 years old Japanese female with malignant masothelioma a showing peculiar stromal change was presented. The tumor had occupied the abdominal cavity around the uterus and both ovaries, and was diagnosed as a malignant peritoneal mesothelioma of epithelial type. The characteristic feature of the tumor was that the foam cells, which contained abundant amount of lipid droplets in the cytoplasm, and were thought to be histiocytes, massively occupied the stroma of the papillary tumor. Macroscopically, the tumor simulated a codfish roe. To our knowledge, no case of this sort of appearance of mesothelioma has ever been reported. ACTA PATHOL. JPN. 34: 687–692, 1984.     

Hepatocellular carcinoma with mesothelioma-like dissemination

Reported herein is a case of hepatocellular carcinoma (HCC) with unusual peritoneal dissemination masquerading as peritoneal mesothelioma. A 61-year-old man was clinically found to have multiple tumors in his abdominal cavity; peritonitis carcinomatosa was suspected. An autopsy revealed numerous tumors of various sizes in the abdominal serosa, omentum, and diaphragm. No signs of tumor, fibrosis, or cirrhosis were found in the liver, except for a small nodule in the hepatic triangular ligament. Histologically, the tumor cells proliferated in thick trabeculae or in sheets and formed a few canaliculi and tubules with homogenously brown contents in their lumina, which stained positively with Hall stain. Immunohistochemically, these tumors were positive for hepatocyte, alpha-fetoprotein (AFP) and low-molecular-weight cytokeratin; were focally positive for pan-cytokeratin and epithelial membrane antigen (EMA); and were negative for high-molecular-weight cytokeratin, vimentin, and calretinin. Carcinoembryonic antigen (CEA) produced a bile canalicular immunohistochemical staining pattern. Thus, the tumor was diagnosed as an HCC (Edmondson II type) of the triangular ligament with massive peritoneal dissemination. The origin of this tumor and its differential diagnosis (malignant mesothelioma, hepatoid adenocarcinoma, and hepatoid yolk sac tumor) are discussed.     

Expression of cytokeratin 5/6 in epithelial neoplasms: an immunohistochemical study of 509 cases.

Cytokeratin 5/6 (CK 5/6) immunoreactivity has been observed in the vast majority of cases of malignant mesothelioma but only rarely in pulmonary adenocarcinomas. Thus, CK 5/6 has been used to distinguish malignant mesothelioma from pulmonary adenocarcinoma. However, the utility of CK 5/6 in distinguishing pleural malignant mesothelioma from pleural metastases from nonpulmonary adenocarcinoma, as well as peritoneal malignant mesothelioma from peritoneal metastatic adenocarcinoma, has not yet been adequately addressed because the tissue expression of CK 5/6 in nonpulmonary neoplasms has not been well defined. We have studied the CK 5/6 expression in 509 cases of various epithelial tumors by immunohistochemistry. We found that the vast majority of cases of squamous cell carcinoma, basal cell carcinoma, thymoma, salivary gland tumor, and biphasic malignant mesothelioma were positive for CK 5/6. In addition, CK 5/6 immunoreactivity was detected in 15 of 24 cases (62%) of transitional cell carcinoma, in 5 of 10 cases (50%) of endometrial adenocarcinoma, in about one third of cases of pancreatic adenocarcinoma (38%) and breast adenocarcinoma (31%), and in one quarter of cases of ovarian adenocarcinomas (25%). Our study confirms the diagnostic utility of CK 5/6 immunohistochemistry in distinguishing biphasic mesothelioma from pulmonary adenocarcinoma but raises caution about its use for the differential diagnosis of pleural or peritoneal malignant mesothelioma versus pleural or peritoneal metastatic nonpulmonary adenocarcinoma, because many types of nonpulmonary adenocarcinomas may be positive for CK 5/6.