Diffuse malignant peritoneal mesothelioma in a 13-year-old girl. Report of a case and review of the literature

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) with cisplatin in pediatric patients with peritoneal mesothelioma: a single institution experience and long term follow up

INTRODUCTION

Malignant peritoneal mesothelioma (MPM) is a lethal cancer, with approximately 2% of diagnoses occurring in patients less than 40 years of age. The purpose of this study is to report the only long-term follow up and survival of pediatric patients with MPM after multi-modality therapy including cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

We retrospectively investigated a prospectively maintained database including patients <21 years old who underwent CRS and HIPEC from 1994 through 2014. Follow-up information was available through 2019 and is included in this report.

RESULTS

Seven young patients underwent CRS and HIPEC. Final histology was epithelioid in all patients. Three patients had received neo-adjuvant systemic chemotherapy. At the time of the operation Peritoneal Cancer Index ranged from 6 to 25. Completeness of cytoreduction score after CRS was 0 in 4 patients, 1 in two patients, and 2 in one patient. Post-operative complications included acute kidney injury (n = 1), hyperbilirubinemia (n = 1), bilateral pleural effusions (n = 1) and pneumothorax requiring chest tube placement (n = 1). At last available follow-up, 71% of patients (n = 5) were alive with minimal or no evaluable disease. The remaining two patients had passed away from their disease at 14 and 26 months, respectively, following CRS and HIPEC. Overall survival ranged between 14 and 281 months.

CONCLUSION

Our surgical experience shows that CRS and HIPEC is a feasible and safe treatment option in pediatric patients, potentially improving overall survival.

Clinical significance of histologic subtyping of malignant pleural mesothelioma

Malignant mesothelioma (MM) is uncommon, but very aggressive tumor arising from the mesothelial cells of pleura, pericardium, peritoneum, and tunica vaginalis. Despite multimodality treatments 5-year survival is only 5% after the diagnosis. Histology and TNM staging system are still the best prognostic factors. Furthermore, histologic subtype of MM determines the clinical management of the patients. According to the 2015 WHO classification, MM is divided into diffuse, localized and well differentiated papillary mesothelioma. Major histologic subtypes of diffuse MM, namely epithelioid, biphasic and sarcomatoid, have different prognosis. However, in the last decade it has become evident that more detailed subclassification and histologic/cytological characterization of MM have prognostic and perhaps predictive implications. In this review, major histologic subtypes and cytological features of MM are presented and their relation with prognosis and predictive biomarkers is discussed.

Deciduoid type malignant pleural mesothelioma: a case report

Here, we report a patient with deciduoid type malignant pleural mesothelioma (MPM), which rapidly progressed. A 55-year-old man who might have been exposed to asbestos a few decades ago had severe back pain. The chest X-ray scanning and computed tomography (CT) revealed pleural thickness on his right thoracic space, without the presence of a lung mass. A pleural biopsy was performed and the patient was histologically diagnosed with deciduoid type MPM. Although he received two cycles of chemotherapy, his disease rapidly progressed and he died within two months of the diagnosis of deciduoid type MPM.

Primary Malignant Deciduoid Mesothelioma: A Challenging Diagnosis

Primary malignant deciduoid mesothelioma is a rare subtype of epithelioid mesothelioma that was first described in the peritoneum in young women without a history of asbestos exposure. It was thought to be a distinct clinicopathologic entity with ominous prognosis; recent studies have better characterized this entity. On morphology, primary malignant deciduoid mesothelioma is characterized by cytomorphologic features resembling decidualized tissue. Pleomorphism is variable. The immunoprofile is similar to other epithelioid mesotheliomas. The prognosis is the same as other epithelioid mesotheliomas and seems to depend on histological grade.

Malignant Deciduoid Mesothelioma: case presentation of an exceptional variant and review of the literature

BACKGROUND

Malignant Deciduoid Mesothelioma (MDM) is an extremely rare variant of epithelioid mesothelioma. It was first described in young females, in the peritoneum, and its relation with asbestos was not well defined. Later reports, have shown that this variant may also occur in the pleura, the pericardium and the tunica vaginalis of elderly people, who had been exposed to asbestos.

CASE PRESENTATION

We report a case of malignant deciduoid mesothelioma that occurred in the peritoneal cavity, and the omentum of a 35-year-old woman. The patient had never been exposed to asbestos.

CONCLUSIONS

Through this observation, we describe clinical, histopathological, and immunohistochemical findings of deciduoid mesothelioma, and review the literature reports.

Deciduoid mesothelioma of the thorax: A comprehensive review of the scientific literature

OBJECTIVE

Deciduoid mesothelioma is a rare variant of malignant epithelioid mesothelioma. It often involves the peritoneum, but also thoracic cases have been reported. The aim of the present review is to describe the demographic, clinical, radiological, and pathological features of such a rare variant of thoracic mesothelioma, and the state of the art regarding the therapeutic approaches currently available.

DATA SOURCE

English-language articles published from 1985 to June 2016, and related to thoracic deciduoid mesothelioma cases were retrieved using the Pubmed database.

STUDY SELECTION

The search terms were "mesothelioma," "thoracic mesothelioma," "epithelial mesothelioma," "pleural mesothelioma," and "deciduoid mesothelioma."

RESULTS

Forty-four cases included in 16 articles, published in the period under investigation, were analyzed in detail.

CONCLUSIONS

The mean age of the patients was 63 years, and the male to female ratio 1.7:1. Approximately 58% had exposure to asbestos, and 73% had a smoking history; familiarity was rarely reported. The most common anatomical site of origin was the right pleura, and the most frequent clinical manifestations were chest pain, dyspnea, cough, and weight loss. Thoracic X-ray and computed tomography were the imaging techniques most employed for diagnosis and surgical planning. The pathological diagnosis was obtained by examination of surgical or biopsy specimens in most cases. The best treatment strategy of deciduoid mesothelioma is a matter of debate; nevertheless a multidisciplinary approach is currently the best option for the choice of the adequate therapeutic scheme.

Peritoneal Mesothelioma

Previous imaging reports of peritoneal mesothelioma have described a variety of radiologic appearances, but have not included its pathologic classification. We retrospectively reviewed 10 cases of peritoneal mesothelioma representing the following histologic categories: 7 epithelial, 2 sarcomatoid, and one biphasic. By imaging, epithelial mesotheliomas demonstrated diffuse thickening of the peritoneum and mesentery and/or multiple small nodules. The sarcomatoid-type appeared as a mass and the biphasic-type had radiologic and gross pathologic features of both sarcomatoid and epithelial types. We conclude that peritoneal mesothelioma presents with a wide spectrum of radiographic appearances and should therefore be included in the differential diagnoses of diffuse as well as localized peritoneal processes.

Diffuse Histiocytic Proliferation Mimicking Mesothelial Hyperplasia in Endocervicosis of the Female Pelvic Peritoneum

Two cases of a diffuse histiocytic proliferation that mimicked mesothelial hyperplasia in the pelvic peritoneum of premenopausal women with endocervicosis are presented. The lesions were found incidentally on laparoscopic examination for pelvic pain and appeared as small friable excrescenses attached to the serosal surface of the pelvis. Histologic examination revealed a dense proliferation of round to oval cells with abun dant eosinophilic cytoplasm and large, hyperchromatic nuclei showing focal invagina tions and occasional mitoses. The cells appeared to infiltrate the surrounding connec tive tissue in single files and were closely associated with sloughed strands of small, cuboidal mesothelial cells as well as with larger glands lined by mucinous epithelium. Immunohistochemical studies showed cytoplasmic staining of these cells with MAC387, HAM56, and alpha-1-antichymotrypsin antibodies, thus supporting their histiocytic nature. The close association of the histiocytic proliferation with the endo cervicotic glands raises the possibility that the process may have resulted as a reaction to rupture and extrusion of the mucous contents of the glands into the surrounding stroma. These lesions must be distinguished from reactive or neoplastic mesothelial proliferations involving the female pelvic peritoneum. Int J Surg Pathol 1(2):101-106, 1993

Deciduoid Peritoneal Mesothelioma in a Dog

Deciduoid mesothelioma is a rare variant of epithelial mesothelioma, up to now only described in human pathology, which bears remarkable cytomorphologic resemblance to the endometrium of pregnancy, termed decidua. A case of peritoneal mesothelioma with deciduoid features in a 10-year-old, female dog is reported. Multiple whitish-gray nodules (1-5 mm in diameter) in parietal peritoneum and mesentery were histologically composed of large, proliferating, polygonal or ovoid cells with an abundant eosinophilic, glassy cytoplasm. Immunohistochemical evaluation indicated that the neoplastic cells coexpressed cytokeratin and vimentin with strong and diffuse cytoplasmic staining, and ultrastructural analysis showed long and slender mesothelial-type microvilli; these findings confirmed the mesothelial origin of the tumor.

An 8-Year-Old Child with Malignant Deciduoid Mesothelioma of the Abdomen: Report of a Case and Review of the Literature

Malignant mesothelioma is an uncommon tumor that usually arises in the pleural cavity of adults with a history of asbestos exposure. Less frequently, it appears in the peritoneum or other mesothelial surfaces. Deciduoid mesothelioma is a rare subtype that has been found at both sites. Of the 3 reported cases in children, 2 originated in the mesenterium and 1 in the pleura. We describe a 4th case of pediatric, malignant, deciduoid mesothelioma and a third case in the mesenteric cavity. The patient was an 8-year-old girl who presented with abdominal pain and fullness. Workup revealed extensive involvement of the abdomen by a serosa-based tumor. The clinical and pathologic findings are described, and the pertinent literature is reviewed.

An Autopsy Case Report of Malignant Pleural Mesothelioma with Deciduoid Features

Deciduoid mesothelioma is a rare variant of epithelioid mesothelioma. We experienced the case of a 73-year-old man with asbestos exposure who was diagnosed with malignant pleural mesothelioma with deciduoid features. He received chemotherapy containing six cycles of cisplatin and pemetrexed and survived for twenty-five months after the diagnosis. At autopsy, the final diagnosis was biphasic pleural mesothelioma. Cells with deciduoid features had mostly disappeared, and spindle cells markedly proliferated. To the best of our knowledge, this is the first autopsy case of malignant pleural mesothelioma with deciduoid features that exhibited a response to chemotherapy.

Deciduoid mesothelioma: report of 21 cases with review of the literature

Deciduoid mesothelioma is a rare variant of epithelioid mesothelioma that was initially considered to occur exclusively in the peritoneum of young women who had no history of asbestos exposure and to be characterized by an aggressive clinical course, but it was later demonstrated that this tumor could also occur in the pleura of older men and women who had been exposed to asbestos. Some subsequent studies have also indicated that the clinical course is no different from that of conventional epithelioid mesothelioma. Herein are reported 21 cases of deciduoid mesothelioma that were investigated using a large panel of immunohistochemical markers, 9 of which were also studied by electron microscopy. Fifteen of the patients were male and 6 were female (mean age, 60 years). Seventeen of the cases originated in the pleura and four in the peritoneum. Histologically, all of the cases were composed of large, polygonal or ovoid cells with well-defined cell borders, dense eosinophilic cytoplasm, and single or multiple nuclei. In some cases, the cells exhibited a wide variation in their size and shape, frequent loss of cell cohesion, marked nuclear atypia, and high mitotic activity (>5 per 10 HPF); whereas, in others, the cells were more cohesive, less pleomorphic, and the mitotic activity low. As the survival of patients in the first group of cases was shorter (mean, 7 months), when compared with that of the latter (mean, 23 months), it is concluded that the differences in prognosis reported in deciduoid mesothelioma are due to the existence of a high-grade subgroup that presents highly aggressive clinical behavior. Therefore, when a high-grade deciduoid mesothelioma is present, it should be reported as it can significantly affect prognosis and treatment. The use of immunohistochemistry and electron microscopy in assisting in the differential diagnosis of deciduoid mesothelioma is also discussed.

The use of immunohistochemistry in the diagnosis of composite and collision tumors: exemplified by pleural mesothelioma and carcinoid tumor of the lung

A case of a collision lymph node metastasis of a mesothelioma and a carcinoid tumor in a 73-year-old man with a history of asbestos exposure is reported. An interesting finding in this case was that both the mesothelioma and its lymph node metastases exhibited a wide variety of histologic patterns, including one characterized by a solid growth of large cells with abundant, clear, and foamy cytoplasm and another exhibiting deciduoid features. Pathologists should be aware that mesotheliomas can present very unusual morphologic features, such as those seen in the present case, and therefore, should be included in the differential diagnosis of those tumors that can display similar morphology and can metastasize to the serosal membranes. Reexamination of the pneumonectomy specimen in the current case identified a primary peripheral carcinoid tumor. The recognition of a nonasbestos-related tumor in a patient with mesothelioma is important since its presence may have an impact on the patient's life expectancy and, therefore, may affect any compensation settlement.

Deciduoid pleural mesothelioma--a rare entity in a young woman

Deciduoid Mesothelioma is a rare variant of epithelioid mesothelioma; it was initially thought that it only occurred in the peritoneum of young women and had nothing to do with asbestos exposure. However, since these early findings it has also been observed in the pleura and the pericardium, with possible association to asbestos. In general the prognosis is poor compared to epithelioid mesothelioma. 45 cases have been reported in the literature up to now, 22 of these were located in the pleural cavity. The authors describe a case of deciduoid pleural mesothelioma in a 40-year-old-woman who presented with right pleuritic chest pain, with no history of asbestos exposure, treated with chemotherapy followed by surgery and who died postoperatively.

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.

Primary malignant deciduoid peritoneal mesothelioma: a report of the cytohistological and immunohistochemical appearances

Malignant deciduoid mesothelioma (MDM) is a rare variant of epithelioid mesothelioma. This type of tumor might be associated with the asbestos exposure and carries a poor prognosis in general. MDM was first described by Nascimento et al. in 1994 in a peritoneal lesion of a young woman. And its diagnosis is frequently mistaken with florid mesothelial hyperplasia and peritoneal deciduosis. There are 44 MDM cases reported in the literature up today. A 59-year-old woman patient referred to our clinic was identified with an abdominal mass. Computed tomography of whole abdomen of the patient showed a mass with the widest transverse dimension of 65 × 60 mm at abdominal bifurcation in the mesenteric region. The patient was diagnosed with MDM after the cytopathological examination of the fine needle aspiration biopsy performed from the mass. Consequently, she received a total mass excision and right hemicolectomy under general anesthesia. The cytomorphological appearance of the ascitic fluid is detailed for the first time by Gillespie et al. and is described only in two manuscripts. In the present study, we aimed to report a case of a 59-year-old woman since she was diagnosed with MDM and because her cytological findings were further supported by histomorphological and immunohistochemical evaluations of the operation material obtained from the patient.

Extrathoracic Mesothelial Proliferations and Their Mimics

Mesothelial proliferations, either reactive or neoplastic in nature, often pose difficult diagnostic dilemmas. Electron microscopy continues to be a gold standard in the identification of mesothelial differentiation. However, it is very common to apply long panels of antibodies for that purpose. In most cases, light microscopy and immunohistochemistry will solve the problem. However, the definitive, specific, and sensitive immunohistochemical marker is still lacking. This is particularly true in peritoneal and testicular mesothelial tumors, in which common embryologic origin with epithelial elements results in overlapping immunohistochemistry and morphology. The particularities of peritoneal and testicular mesothelial proliferations, and the main tumors that may mimic them in these sites, as well as the value and limitations of immunohistochemistry and electron microscopy in their differential diagnosis are the subject of this review.

[Deciduosis causing perforating appendicitis in the early postpartum period following caesarean section]

Case history of a 29-years-old primigravida is reported, by whom in the 39th week of the pregnancy an acute caesarean section was performed for intrauterine fetal distress. On the 5th postoperative day symptoms of acute abdomen developed, with typical signs of an appendicitis. On emergency laparotomy a perforated processus vermiformis had been removed, displaying gangrenous inflammation. Histological examination of the removed tissue revealed deciduosis, involving all layers of the intestinal wall. The article is the first Hungarian report on deciduosis involving the appendix, and the first international paper reporting on an appendicectomy for deciduosis following caesarean section summarizes the origin, the signs and the therapeutical consequences of this rare diagnostic entity.

Comparative genomic hybridisation in malignant deciduoid mesothelioma

BACKGROUND

Malignant deciduoid mesothelioma is a rare variant of epithelioid mesothelioma. This tumour generally has poor prognosis, and can be asbestos related.

AIM

To identify peculiar genetic changes responsible for critical phases in pathogenesis of malignant deciduoid mesothelioma and their prognostic relevance.

METHODS

Comparative genomic hybridisation was carried out in six cases of malignant pleural deciduoid mesothelioma, four sporadic and two familial. All cases were found to be asbestos related. Four patients died during follow-up and the mean survival was 29.5 (SD 14.2, range 12-43) months.

RESULTS

Genetic abnormalities were found in all the tumour tissues, the most frequent being chromosomal gains at 1p, 12q, 17, 8q, 19 and 20 and losses at 13q, 6q and 9p. Survival was found to be longer in those patients who presented a smaller number of losses (< or =2) in the tumorous chromosomes.

CONCLUSIONS

Although numerous genetic changes are presented by deciduoid mesotheliomas, certain chromosomal regions are preferentially affected. The clinical outcome for this mesothelioma subtype is predicted by the number of losses.

Malignant deciduoid mesothelioma: a diagnostic challenge

Malignant deciduoid mesothelioma, a rare phenotype of epithelioid mesothelioma, arises more commonly from the peritoneum of young women, but it is also reported in the pleura of elderly people. We report a case of malignant deciduoid mesothelioma that occurred in a 41-year-old woman after cesarean section and was initially misdiagnosed as pseudotumoral deciduosis. Microscopically, the tumor was entirely composed of deciduoid areas, and only scattered tumor cells were positive for calretinin and keratin 5/6. The patient died 14 months after the first operation. This observation confirms the poor prognosis of this entity and the importance of the differential diagnosis of pseudotumoral deciduosis.

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.

Primary malignant mesothelioma of the peritoneum: a clinical and immunohistochemical study

BACKGROUND

Primary peritoneal mesothelioma is regarded as a fatal disease that presents with progressive ascites at a relatively late stage of its natural history. Differential diagnosis between this rare tumor and both serous papillary carcinoma of the peritoneum and ovary can be problematic.

CASE

A 54-year-old woman presented to our institution with a 4-month history of dull epigastric pain and increased abdominal girth. Exploratory laparotomy revealed the presence of extensive intraperitoneal dissemination of a malignant neoplasm without a recognizable primary site. Suboptimal cytoreduction was carried out, and histological diagnosis was that of a malignant epithelioid mesothelioma. This was confirmed with a panel of immunohistochemical markers. The patient despite having a complete response after adjuvant chemotherapy died 18 months after primary surgery.

CONCLUSION

No single immunohistochemical stain is pathognomonic of peritoneal primary malignant mesothelioma (PMM), and the results of a panel of antibodies should be interpreted to set the diagnosis.

Deciduoid mesothelioma in the pelvic cavity

A very rare case of deciduoid mesothelioma in the pelvic cavity is presented. A 24-year-old woman (gestational stage: 28 weeks and 6 days) was admitted because of a tumor mass in the abdominal cavity. A well-circumscribed and fibrously encapsulated tumor mass was revealed in the Douglas cavity. Histologically, tumor cells were arranged in a solid sheet with deciduoid appearance and showed partial glandular and papillary structures. The tumor cells contained PAS positive and diastase-digested granules in the cytoplasm as well as alcian-blue positive and hyaluronidase-digested substances in the stroma. The cellularity of the tumor cells was moderate and mitoses were rare. There was partial tumor necrosis and tumor cells had infiltrated through the fibrous capsule. Immunohistochemically, the tumor cells were reactive for pancytokeratin, cytokeratin5/6, vimentin, HBME-1, calretinin and thrombomodulin. Ultrastructurally, numerous, long microvilli, tonofilaments and desmosome junctions could be seen. Consequently, this case was diagnosed as deciduoid mesothelioma and 2 years and 4 months after operation, the patient's clinical course has been good. This case is considered to be the first reported in Japan.

Malignant deciduoid mesothelioma of the pleura: report of two cases with long survival

AIMS

To present two rare cases of malignant mesotheliomas with deciduoid features arising in the pleura, both with long survival.

METHODS AND RESULTS

These two cases of deciduoid mesotheliomas were observed in adult patients (one 73-year-old male and one 23-year-old female). Only the male had a history of occupational asbestos exposure, whereas the woman had a history of familial mesothelioma. A deciduoid morphology was predominant and focal areas with tubular-papillary features were noted. The tumour cells were positive for cytokeratins, HMBE-1, calretinin, EMA and mitochondrion antibodies. The follow-up data did not suggest a particularly poor prognosis; the mean survival observed was 23 months (17 and 39 months, respectively).

CONCLUSIONS

This deciduoid mesothelioma histological subtype does not appear to represent an unfavourable prognostic category.

Primary epithelial malignant mesothelioma of the pericardium with deciduoid features: cytohistologic and immunohistochemical study

Malignant mesothelioma with deciduoid features (MMWDF) is a recently characterized morphologic variant of epithelioid malignant mesothelioma, which frequently is misdiagnosed as peritoneal deciduosis or florid mesothelial hyperplasia. We report on the cytological, histological, immunohistochemical, and autopsy findings of a case of MMWDF arising in the pericardium of a 71-yr-old female patient. Cytology showed large, polygonal to round cells with pale to bright, eosinophilic cytoplasm, occasionally showing xantomatous pattern, containing a pleomorphic and vesicular nucleus with a single prominent nucleolus. Autopsy examination showed a neoplasm encasing the heart and great vessels. No other primary neoplasm was found. The histological analysis disclosed the typical features of MMWDF. Immunohistochemistry showed diffuse immunoreactivity for cytokeratin MNF116, HBME-1, and calretinin in the neoplastic cells, as well as focal positivity for epithelial membrane antigen positivity in a brush border-like pattern. All other markers were negative. We would like to stress that pathologists must be aware of the cytological and histological features of this rare variant of epithelioid malignant mesothelioma in order to avoid a misdiagnosis of a benign process or a metastatic malignancy.

An autopsy case of a malignant pericardial mesothelioma in a Japanese young man

An autopsy case of a malignant pericardial mesothelioma in a 27-year-old man with no history of exposure to asbestos is reported. He was admitted for heart failure due to pericardial effusion of unknown origin and surgically drained, but later died. The diagnosis of a malignant pericardial mesothelioma was made on the basis of histologic, immunohistochemical and ultrastructural findings. The tumor was located on the pericardium, but autopsy revealed that it had spread extensively in the mediastinum and the lungs. Microscopically, the tumor cells were epithelial like and contained histochemically demonstrable glycogen and hyaluronic acid. Immunohistochemical studies of the tumor demonstrated positive immunoreactivity for cytokeratin 19, muscle actin HHF35, epithelial membrane antigen, CA125, p53 and p21WAF1/CIP1 whereas the tumor was negative for cytokeratins 10 and 17, carcinoembryonic antigen, vimentin, epithelial antigen BerEP4, S-100, c-erbB2 and bcl-2. A high MIB-1 labeling index was noted. Under the electron microscope the tumor cells exhibited long, thin villi. The operation and autopsy findings thus revealed this to be a very rare case of malignant pericardial mesothelioma in a young man.

Cystic mesothelioma of the peritoneum: a rare cause of 'ascites' in children

A 2-year-old girl presented with a 3-month history of progressive painless abdominal distension. Results of the clinical examination suggested massive ascites, but no other symptoms or signs could be elicited. There was no history of any other illness preceding the onset of distension. Ultrasonography and a computed tomography scan confirmed gross ascites, with multiple thin-walled loculi throughout the abdomen, from the diaphragm to the pelvis. The preoperative diagnosis was intraabdominal lymphangioma. During laparotomy, multiple transparent cysts were found throughout the peritoneum. There was no evidence of malignancy in any organ, and the cysts appeared almost completely avascular. Histological and ultrastructural appearances were those of benign cystic mesothelioma of the peritoneum, a condition that hitherto has been recognized only in adults. It is thought to represent a borderline variant between a truly benign adenomatoid lesion and the better-known malignant mesothelioma. The experience with adult cases suggests a high potential for recurrence but no progression to malignancy. It is possible that some cases of intraabdominal lymphangioma may have been misdiagnosed in the past; future cases should be fully evaluated, both immunohistochemically and ultrastructurally, to establish the true incidence of mesothelial proliferative disease in children.

Diffuse malignant peritoneal mesothelioma in a young woman with a high serum level of CA125

An autopsy case of diffuse malignant peritoneal mesothelioma in a young woman who showed a high serum level of CA125 is reported. Autopsy revealed extensive tumor involvement of the visceral and parietal peritoneum. The liver, spleen and other abdominal viscera were encased by tumor nodules. Histologically, the polygonal tumor cells were arranged mostly in a sheet-like fashion with a few tubular or papillary forms. No PAS reaction-positive mucin was recognized, but there was a strongly positive colloidal iron reaction. The colloidal iron positivity was effaced after combined treatment with hyaluronidase and sialidase. Immunohistochemically the tumor cells showed strongly positive reactions for CA125, epithelial membrane antigen (EMA) and cytokeratin, weak positivity for carcinoembryonic antigen (CEA) and focal positivity for vimentin. Ultrastructurally, the most characteristic feature was the expression of numerous long microvilli projecting from the tumor cell surfaces and abundant long desmosomes between the tumor cells. We consider that pretreatment using a combination of hyaluronidase and sialidase might be useful for the diagnosis of malignant mesothelioma. CA125 staining should be performed routinely in cases where this tumor is suspected.

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.

Serous surface carcinoma of the peritoneum: a clinicopathologic study of 22 cases

Serous surface carcinoma (SSC) of the peritoneum is defined as a primary tumor histologically indistinguishable from serous carcinoma of the ovary, diffusely involving the peritoneal surface but sparing or only superficially invading the ovaries. In this study of 22 cases of SSC, it was found that the main clinical manifestations of SSC were abdominal pain and enlargement. In most cases, SSC evenly involved the entire mesothelial surface but rarely was predominant in or even limited to the pelvis. It frequently invaded the submesothelium, but deep invasion into abdominal and pelvic organs or local metastasis was rare, and distant metastasis was not seen at presentation. Microscopically, SSC was a high-grade tumor frequently showing high mitotic rate, psammomas bodies, and necrosis. The tumor was usually contiguous with hyperplastic mesothelium on either ovarian surface or other locations. Tumor cells in all cases except one showed cytoplasmic or surface neutral or acidic mucin or both. Tumor cells stained positive for keratin (100% of cases), epithelial membrane antigen (100%), Leu-M1 (45%), B72.3 (85%), vimentin (35%), and carcinoembryonic antigen (25%). Electron microscopic studies of six cases showed epithelial differentiation in each. Seven patients (32%) were alive with no clinical disease at 3 to 31 months, one patient (4%) was alive with extensive local disease at 24 months, 11 patients (50%) died almost exclusively of local recurrence at 1 to 70 months, and three patients (14%) died of operative complications. It is concluded that SSC arises from peritoneal mesothelium but has epithelial phenotype. It can be morphologically differentiated from other conditions with similar laparotomy findings, such as malignant mesothelioma, benign papillary mesothelioma, cystic mesothelioma, and benign or borderline peritoneal serous tumors. The prognosis of SSC is poor, and most patients die of uncontrollable local disease.

Mesothelioma of childhood

Malignant mesothelioma (MM) of childhood is a rare but important neoplasm. Eighty children with a previous diagnosis of MM were identified. Four of the 80 children had exposure to known risk factors (two had history of exposure to asbestos, one had received radiation therapy, and one had been exposed in utero to isoniazid). Tissue slides were available for independent and joint review by a panel of three pathologists in 22 of the cases. Ten were accepted as MM, nine were reclassified as other malignancies, and three were considered tumors of uncertain nature. Six of the ten children with MM were boys, and four were girls. Eight had pleural tumors, and two had peritoneal tumors. Four died at 7, 8, 18, and 48 months after diagnosis; three remained alive at 19, 20, and 59 months; and three had no follow-up. This review suggests that MM of childhood is a valid entity with a grave prognosis. The tissue diagnosis is difficult and is best made by a panel of pathologists. The available evidence does not support a causal relationship between MM and asbestos, radiation, or isoniazid.

Congenital malignant mesothelioma. A case report and electron-microscopic study

Malignant mesothelioma was diagnosed in a 16-day-old boy. As far as we know this is the first report of a congenital case of this disease.

Simultaneous immunoenzyme staining of vimentin and cytokeratins with monoclonal antibodies as an aid in the differential diagnosis of malignant mesothelioma from pulmonary adenocarcinoma

The occurrence and coexpression of the cytoskeletal proteins vimentin and cytokeratins were studied in malignant mesotheliomas and pulmonary carcinomas. For this purpose a double immunoenzyme staining with monoclonal antibodies was developed which made it possible to visualize vimentin and cytokeratins simultaneously within the same cell. A clear distinction between stromal cells (vimentin only) and tumour cells was also obtained. A total of 12 mesotheliomas (six mixed type and six epithelioid type) and 13 carcinomas (eight adenocarcinomas and five large cell undifferentiated carcinomas) were studied. The results revealed a clear difference between mesotheliomas and adenocarcinomas: 11 of 12 mesotheliomas showed coexpression of vimentin and cytokeratins in at least 50% of the tumour cells, while in seven of the eight adenocarcinomas none or only a few cells could be seen with this coexpression. In the undifferentiated large cell carcinomas three of five expressed both components, but in less than 25% of the cells. It is concluded that a reliable double immunoenzyme staining of vimentin and cytokeratins can be used as an additional means to distinguish malignant mesothelioma from pulmonary adenocarcinoma.

Primitive cystic hepatic neoplasm of infancy with mesothelial differentiation: report of a case

A malignant cystic neoplasm in the liver of a 6-month-old girl is reported. The neoplasm has unique clinical and morphological features, and despite ultrastructural and immunohistochemical studies, the tumor could not be clearly classified as any known primary hepatic neoplasm of infancy. A differentiated cystic component of the neoplasm had features of cystic peritoneal mesothelioma. Alpha-1-antitrypsin and alpha-fetoprotein were demonstrated in solid, anaplastic portions of the recurrent tumor by immunohistochemistry. The neoplasm recurred after surgical resection and proved fatal 11 months following diagnosis, despite multiple courses of chemotherapy.