Posterior mediastinal epithelioid leiomyosarcoma: Case report and literature review.

Epithelioid type leiomyosarcoma is rarely encountered outside of the abdomen or uterus. We present a case of posterior mediastinal leiomyosarcoma in a 45-year-old male with back pain and bilateral lower extremity weakness. Magnetic Resonance Imaging of the thoracic spine revealed a heterogeneous posterior mediastinal soft tissue mass infiltrating the vertebral body and epidural space with resultant spinal cord compression and edema. Positron Emission Tomography showed no evidence of distant metastatic spread. Histopathological characterization revealed epithelial type leiomyosarcoma. Despite multiple subtotal resections, radiotherapy, and salvage chemotherapy with successful restoration of the patient's neurological function, the tumor burden remained significant. The patient was subsequently lost to follow up and the clinical outcome remains unknown. To our knowledge this is the first reported case of epithelioid type posterior mediastinal leiomyosarcoma presenting with spinal cord compression and edema.

Malignant mesothelioma: A clinicopathological study of 76 cases with emphasis on immunohistochemical evaluation along with review of the literature.

INTRODUCTION: Malignant mesothelioma is an aggressive neoplasm arising from serosal lining and has a poor prognosis. Definite diagnosis requires confirmation through a biopsy; however, it is sometimes difficult on microscopic evaluation alone and requires the use of a wide panel of immunohistochemical markers. So, immunohistochemistry (IHC) is of paramount importance and must be routinely used for a definite diagnosis. Till date, very few studies on morphology and detailed IHC markers of mesothelioma have been reported from India. AIMS: To analyze the histomorphological findings of malignant mesothelioma, study the utility and role of the various immunohistochemical markers. MATERIAL AND METHODS: A total of 76 cases of mesotheliomas diagnosed at a tertiary cancer center in Udaipur were analyzed retrospectively from January 2015 to January 2020. Comprehensive data were analyzed including demographic, clinical, radiological, histopathological features along with a wide panel of IHC markers. RESULTS: Mesothelioma occurs over a wide age range from 40 to 70 years. It most commonly involved pleura in 68 cases (89.47%) with very few cases from the peritoneum. On computed tomography (CT) scan, nodular pleural or peritoneal thickening was present. On microscopy, the most common histopathological type was epithelioid mesothelioma (58 cases, 74.3%) followed by sarcomatous (9 cases, 12.8%), deciduoid (6 cases, 8.6%), and 3 cases of biphasic (4.3%). On IHC, WT1, mesothelin, and calretinin markers were positive in 85.91%, 80%, and 93.33% cases of mesothelioma, respectively. Other markers were helpful to rule out differential diagnosis in difficult scenarios. CONCLUSION: Therefore, the correlation of histopathology with clinico-radiological findings and judicious use of a panel of IHC markers is required for routine evaluation and definite diagnosis. IHC is also useful in situations with similar morphological spectrum in specific locations.

Vaginal epithelioid angiosarcoma: A literature review of a rare entity in an unusual site.

We describe an extremely rare case of a 66-year-old woman with a vaginal epithelioid angiosarcoma. She presented with constitutional symptoms, pelvic pain, vaginal bleeding, and a violaceous vaginal lesion. A thorough gynaecological examination, tissue biopsy and imaging were crucial to establish an accurate diagnosis. With only 3 other cases reported in the literature, epithelioid angiosarcoma of the vagina seem to present late due to their nonspecific presentation and secluded location. Once diagnosed, optimal treatment is difficult to determine and together with the overly aggressive behaviour of these tumours, they are associated with a poor prognosis. To our knowledge, our case study and systematic literature review is the first to compare the management outcomes of epithelioid subtype angiosarcomas of the vagina. The rarity of this pathology contributes to diagnostic difficulties and lack of consensus regarding treatment of angiosarcomas of the vagina.

Possible reversibility between epithelioid and sarcomatoid types of mesothelioma is independent of ERC/mesothelin expression.

BACKGROUND: Mesothelioma is histologically divided into three subgroups: epithelioid, sarcomatoid, and biphasic types. The epithelioid or sarcomatoid type is morphologically defined by polygonal or spindle-like forms of cells, respectively. The biphasic type consists of both components. It is not yet understood how histological differentiation of mesothelioma is regulated. ERC/mesothelin is expressed in most cases of the epithelioid type, but not in the sarcomatoid type of mesothelioma. Consequently, its expression is well correlated to the histological subtype. We hypothesized that ERC/mesothelin expression influences the histological differentiation of mesothelioma, and tested this hypothesis. METHODS: We performed studies using the overexpression or knockdown of ERC/mesothelin in mesothelioma cells to examine its effect on cellular morphology, growth kinetics, or migration/invasion activity, in vitro. We then transplanted ERC/mesothelin-overexpressing and control cells into the intraperitoneal space of mice. We examined the effect of ERC/mesothelin overexpression on mouse survival and tumor phenotype. RESULTS: In vitro cell culture manipulations of ERC/mesothelin expression did not affect cellular morphology or proliferation, although its overexpression enhanced cellular adhesion and the migration/invasion activity of mesothelioma cells. The survival rate of mice following intraperitoneal transplantation of ERC/mesothelin-overexpressing mesothelioma cells was significantly lower than that of mice with control cells. The histological evaluation of the tumors, however, did not show any morphological difference between two groups, and our hypothesis was not validated. Unexpectedly, both groups (ERC/mesothelin-overexpressing and control) of mesothelioma cells that were morphologically monophasic and spindle-like in vitro differentiated into a biphasic type consisting of polygonal and spindle-like components in the transplanted tumor, irrespective of ERC/mesothelin expression. CONCLUSIONS: These results suggested that the histological transition of mesothelioma between epithelioid and sarcomatoid types may be reversible and regulated not by ERC/mesothelin, but by other unknown mechanisms.

An unusual case of chylothorax.

Pleural effusions occur in up to 70% of cases of malignant pleural mesothelioma (MPM). However, MPM rarely presents as a chylous effusion making it a diagnostic challenge. There are only six reported cases to date. Most cases of chylothoraces due to malignancy are due to lymphoma or bronchogenic carcinoma. We report an interesting case of MPM in a 75-year-old man who presented with recurrent chylothorax. He reported a four-month history of dyspnea and chest discomfort. Chest x-ray revealed a pleural effusion. Pleural fluid analysis was consistent with a chylothorax. Pleural fluid cytology was negative for malignancy. Computed tomography of the chest showed pleural calcifications, mediastinal adenopathy and left lung infiltrate. A fine needle aspirate of the lymph node and transbronchial biopsy specimen (TBBX) of the left lung infiltrate showed extensive reactive appearing mesothelial cells but none that appeared malignant. A video assisted thoracoscopic surgery was suggested but the patient declined. He returned 3 months later with recurrent pleural effusion and worsening airspace disease. Thoracentesis revealed a chylothorax again. Repeat analysis of TBBX and lymph node specimens showed extensive reactive appearing mesothelial cells. Due to concern for MPM, ancillary testing was obtained - loss of BRCA1 associated protein (BAP-1) and CDKN2A/p16 gene deletion. BAP1 staining was lost in the mesothelial cells supporting MPM. This case highlights a rare cause of MPM presenting as a chylous effusion. In a patient with an unknown etiology of chylothorax, MPM must remain in the differential.

Multiple malignant epithelioid mesotheliomas of the liver and greater omentum: a case report and review of the literature.

BACKGROUND: Malignant mesothelioma commonly arises from the pleura, but can also arise from the peritoneum, pericardium, and tunica vaginalis testis. However, malignant mesothelioma of the liver is extremely rare and coexistence with malignant mesothelioma of the greater omentum has not been described in the literature. In this case report, we present a case of multiple malignant mesothelioma of the liver and greater omentum. CASE PRESENTATION: A 36-year-old woman was admitted to our hospital for the evaluation of an elastic hard mass in the right upper abdomen. Abdominal contrast computed tomography showed a cystic mass measuring 13 × 14 × 11 cm in the right liver lobe with enhanced mural nodule. Abnormal accumulation was identified in the liver and lower abdominal area on 18F-fluorodeoxyglucose positron emission tomography. The patient underwent hepatectomy of the posterior segment and partial resection of the omentum. The final pathological diagnosis was low-grade multiple malignant epithelioid mesothelioma based on characteristic immunohistochemical findings. As of 6 months postoperatively, the patient has shown no disease recurrence. CONCLUSIONS: We present the first case of a 36-year-old woman with multiple malignant mesothelioma of the liver and greater omentum.

Primary intrahepatic malignant epithelioid mesothelioma.

INTRODUCTION: Primary malignant hepatic mesotheliomas are extremely rare. We report the case of a patient with primary intrahepatic malignant mesothelioma who was treated in our department. PRESENTATION OF CASE: A 66-year old male patient was admitted to our department for the evaluation of anemia. An abdominal computed tomography scan revealed a large space occupying lesion in the right liver lobe. DISCUSSION: The tumor was subsequently resected and a diagnosis of primary intrahepatic malignant mesothelioma was made after pathologic examination. The patient did not receive adjuvant therapy and is currently alive and free of disease, 36 months after the resection. CONCLUSION: To our knowledge this is the eighth adult case of primary intrahepatic malignant mesothelioma reported in the literature. These tumors are rarely diagnosed preoperatively. Absence of previous asbestos exposure does not exclude malignant mesothelioma from the differential diagnosis. Proper surgical treatment may offer prolonged survival to the patient, without adjuvant therapy.

Proceedings of the 2013 Joint JSTP/NTP Satellite Symposium.

The first joint Japanese Society of Toxicologic Pathology (JSTP) and National Toxicology Program (NTP) Satellite Symposium, entitled "Pathology Potpourri," was held on January 29(th) at Okura Frontier Hotel in Tsukuba, Ibaraki, Japan, in advance of the JSTP's 29(th) Annual Meeting. The goal of this Symposium was to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers' presentations, including diagnostic or nomenclature issues that were presented, select images that were used for audience voting or discussion, and the voting results. Some lesions and topics covered during the symposium include: treatment-related atypical hepatocellular foci of cellular alteration in B6C3F1 mice; purulent ventriculoencephalitis in a young BALB/c mouse; a subcutaneous malignant schwannoma in a RccHan:WIST rat; spontaneous nasal septum hyalinosis/eosinophilic substance in B6C3F1 mice; a rare pancreatic ductal cell adenoma in a young Lewis rat; eosinophilic crystalline pneumonia in a transgenic mouse model; hyaline glomerulopathy in two female ddY mice; treatment-related intrahepatic erythrocytes in B6C3F1 mice; treatment-related subendothelial hepatocytes in B6C3F1 mice; spontaneous thyroid follicular cell vacuolar degeneration in a cynomolgus monkey; congenital hepatic fibrosis in a 1-year-old cat; a spontaneous adenocarcinoma of the middle ear in a young Crl:CD(SD) rat; and finally a series of cases illustrating some differences between cholangiofibrosis and cholangiocarcinoma in Sprague Dawley and F344 rats.