Localised pleural malignant mesothelioma. Report of two cases simulating pulmonary carcinoma and review of the literature

Intrapulmonary Biphasic Mesothelioma Misdiagnosed as Adenocarcinoma: Case Report and a Potential Diagnostic Pitfall

Background

Mesothelioma is an uncommon malignant tumor with variable clinical presentations, radiological features, and morphological patterns. Mesothelioma with predominantly intrapulmonary growth presents with an insidious onset, similar radiological and even morphological features to lung cancer, and poses a diagnostic pitfall.

Case Presentation

Herein, we reported a 53-year-old female with biphasic mesothelioma misdiagnosed as poorly differentiated adenocarcinoma with focal sarcomatoid carcinoma. Computed tomography (CT) scan of the chest at the first visit revealed a solid lobulated nodule in the basal segment of the lower lobe of the right lung, which was suspicious of lung cancer. Microscopically, the tumor was composed of epithelioid and spindle cells, both of which were diffusely and strongly positive for CK7, and negative for TTF-1, Napsin A, P40, Melan A, S-100, SMA, and CD34. It was originally misdiagnosed as poorly differentiated adenocarcinoma with focal sarcomatoid carcinoma at initial presentation. Until her second admission with the discovery of a nodule in the right diaphragmatic angle, the peculiar location and biphasic component reminded us of biphasic mesothelioma. Immunohistochemically, tumor cells in both pulmonary and diaphragmatic nodules were positive for calretinin, D2-40, and WT-1, but negative for BerEP4 and MOC31. The patient was treated with a chemotherapy regimen of pemetrexed and carboplatin. After 11 months of follow-up, the patient recovers well without recurrence or metastasis.

Conclusion

Mesothelioma with predominantly intrapulmonary growth is extremely rare and poses a diagnostic pitfall. For this entity, subtle morphological features, selection of immunohistochemical markers, and electron microscopy are of great significance for definite diagnosis.

Localized malignant mesothelioma, an unusual and poorly characterized neoplasm of serosal origin: best current evidence from the literature and the International Mesothelioma Panel

Localized malignant mesotheliomas (LMM) is an uncommon and poorly recognized neoplasm. Its pathologic diagnosis is often surprising in patients with serosal/subserosal based localized tumors that are clinically suspicious for metastatic lesions or primary sarcomas. Once a tumor is diagnosed as "mesothelioma", LMM is often mistaken for diffuse malignant mesothelioma (DMM). Best currently available evidence about LMM was collected from the literature and cases diagnosed by members of the International Mesothelioma Panel (IMP). One hundred and one (101) LMM have been reported in the English literature. Patients had localized tumors with identical histopathologic features to DMM. Patients ranged in age from 6 to 82 years; 75% were men. Most (82%) of the tumors were intrathoracic. Others presented as intrahepatic, mesenteric, gastric, pancreatic, umbilical, splenic, and abdominal wall lesions. Tumors varied in size from 0.6 to 15 cm. Most patients underwent surgical resection and/or chemotherapy or radiation therapy. Median survival in a subset of patients was 29 months. Seventy two additional LMM from IMP institutions ranged in age from 28 to 95 years; 58.3% were men. Sixty tumors (83.3%) were intrathoracic, others presented in intraabdominal sites. Tumors varied in size from 1.2 to 19 cm. Median survival for 51 cases was 134 months. Best evidence was used to formulate guidelines for the diagnosis of LMM. It is important to distinguish LMM from DMM as their treatment and prognosis is different. A multidisciplinary approach is needed for the diagnosis of LMM as it shows identical histopathology and immunophenotype to DMM.

Localized malignant pleural mesothelioma mimicking an anterior mediastinal tumor

Localized malignant pleural mesothelioma (LMPM) is an extremely rare tumor. We report the case of a 40-year-old Japanese male with an LMPM mimicking an anterior mediastinal tumor due to invasion to the anterior mediastinum, and we discuss mainly the differentiation of LMPM from an anterior mediastinal tumor. The present tumor had a long shape along the pleura, and LMPM could be one of the differential diagnoses.

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.

What is the survival after surgery for localized malignant pleural mesothelioma?

A best evidence topic in thoracic surgery was written according to a structured protocol. This was with the purpose of assisting our management of patients with localized malignant mesothelioma of the pleura (LMM). Although the terminology is used inconsistently, this variant has been formally defined by the WHO as a distinct entity defined as localized disease histologically identical to the diffuse form but without any evidence of pleural spread. Treatments for LMM include different combinations of surgery, chemotherapy and radiotherapy. There is an impression that LMM may have a better outcome than the commoner diffuse form of malignant mesothelioma that has been reported to have a survival between 8 and 14 months. In order to advise our patients on prognosis, we studied the duration of survival after surgical resection of LMM. A total of 150 papers were found, of which 16 represented the best evidence to answer the question. The authors, journal, date, country of publication, study type, relevant outcomes and results of these papers are tabulated. It is difficult to combine the results of these 16 papers because both treatments and results are reported differently. Some report median survival (range: 11.6-36 months) and others disease-free survival (range: 0 months to 11 years). Median survival to the longest follow-up was 29 months when calculated by pooling data from informative papers using the Kaplan-Meier method. Our review suggests that survival in LMM is longer than that generally quoted for the more common diffuse form of malignant mesothelioma. Hence, aggressive treatment of LMM may be reasonable in appropriate patients.

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.

Epithelioid Lesions of the Serosa

Context.—Diagnosing epithelioid serosal lesions remains a challenge because numerous different processes—primary or secondary, benign or malignant—occur in body cavities, some of which are very rare.

Objectives.—To review the newest literature and to describe the morphologic criteria and immunohistochemical markers that are useful for distinguishing epithelioid serosal lesions.

Data Sources.—Previously published literature concentrating on the newest research findings. Earlier reviews are principally referred to for established diagnostic criteria.

Conclusions.—Immunohistochemistry with a panel of antibodies has made the diagnosis of epithelioid serosal lesions very reliable. When deciding on antibodies used in differential diagnosis, it is important to consider tumor location, clinical and radiologic information, and morphologic features. Immunohistochemistry is less useful in the differential diagnosis of benign versus malignant mesothelial lesions. The diagnosis of benign versus malignant mesothelial proliferations still relies on the histologic criteria of invasion.

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.