Solitary fibrous tumour of the chest wall.

Extrapleural solitary fibrous tumours (SFTs) are rare tumours characterized by patternless spindle cells with haemangiopericytoma-like vascular spaces. Previously the tumours have been classified as haemangiopericytoma, an entity that is now considered obsolete. We report a case of extrapleural SFT arising in the soft tissue of the chest wall. The patient was a 31-year-old Malay lady presenting with a mobile swelling of the right chest wall for more than five years. During excision the tumour was noted to be well-circumscribed and yellowish in colour, giving an impression of lipoma. Microscopically, the tumour had patternless architecture, characterized by hypocellular and hypercellular areas. It was composed of uniform, spindle-shaped cells displaying oval nuclei, inconspicuous nucleoli, pale cytoplasm and indistinct cell borders. The mitotic count was 2 per 10 HPF. Branching, medium-sized thin-walled blood vessels in a haemangiopericytomatous growth pattern, some with hyalinised wall were identified. The neoplastic cells were immunoreactive to CD99 and CD34 and were non-immunoreactive to Desmin, Smooth Muscle Actin, S100 protein and EMA. We elucidate the challenges in diagnosing this tumour in this unusual location.

A subcutaneous pleomorphic hyalinizing angiectatic tumor of soft parts of the right chest wall: report of a rare case.

Pleomorphic hyalinizing angiectatic tumor of the soft parts is an extremely rare mesenchymal tumor consisting of spindled and pleomorphic tumor cells and clusters of ectatic, fibrin-lined vessels. It typically occurs in the subcutaneous tissues of the distal extremities, usually the ankles and feet. Here we present a case of pleomorphic hyalinizing angiectatic tumor of the soft parts of the right chest wall in a 51-year old female. The tumor was subcutaneous, nonencapsulated, and about 2.0 cm×1.0 cm. Microscopically, the tumor was composed of numerous ectatic, fibrin-filled, thin-walled blood vessels, surrounded by spindled or pleomorphic tumor cells arranged in sheet-like or fascicular architecture, or randomly. Mitotic activity of the tumor cells was low. Immunohistochemical analysis shows that the tumor cells were positive for CD34 and vimentin, but negative for CD31, CK, desmin, EMA, HMB45, Myo D1, P63 and S-100. Ki67 index was about 1%.

Sclerosing rhabdomyosarcoma of a chest wall in an adult: a case report and review of the literature.

Sclerosing rhabdomyosarcoma (SRMS) is a newly recognized and rare variant of rhabdomyosarcoma. This soft tissue tumor has not yet been reported as a thoracic lesion. We report a case of a 26-year-old woman who presented with a large chest wall tumor. The tumor originated from the right anterior chest wall and protruded into the intra- and extrapleural cavity. A transcutaneous needle biopsy revealed spindle cells in an abundant hyalinized and fibrous stroma. Although the tumor was considered as a malignant soft-tissue neoplasm, a definitive diagnosis could not be established. A wide excision of the chest wall including the second, third and fourth rib and a part of sternum was performed. Histologically, cytoplasmic cross-striations were found in a portion of the tumor cells. The tumor cells were positive for muscle markers, and the tumor was diagnosed as rhabdomyosarcoma consistent with a sclerosing type of rhabdomyosarcoma. Eighteen months after the complete resection, the patient has pleural disseminations but is alive and undergoing chemotherapy. This case highlights the histologic features of a rare form of rhabdomyosarcoma, and emphasizes the importance of awareness of its existence and the utility of skeletal muscle markers in distinguishing sclerosing rhabdomyosarcoma from its mimics.

Epithelioid angiosarcoma at chest wall which needs to be carefully distinguished from malignant mesothelioma: report of a rare case.

Angiosarcoma is a malignant soft tissue tumor the cells of which variably recapitulate the morphologic and functional features of normal endothelium. Most lesions are located in the deep muscles of the lower extremities followed by the arm, trunk and head and neck. Herein we present a case of epithelioid angiosarcoma which is a variant of angiosarcoma at chest wall in a 73-year-old female. Morphologically, the tumor cells are arranged predominantly in luminal structures which can be seen in both angiosarcoma and malignant mesothelioma. Most of the tumor cells are large rounded "epithelioid" cells with abundant eosinophilic cytoplasm which can be also seen in both tumors. The epithelioid of cytomorphology and the localization at chest wall of this case may remind of a diagnosis of malignant mesothelioma which should be carefully distinguished from epithelioid angiosarcoma from imaging and morphology. CT scanning of the patient shows a mass at her chest wall, the majority of which is around the rib but not inside the lung which indicates a tumor originates more likely from soft tissues of chest wall but not pleura. Immunohistochemical staining shows that the tumor cells are positive for cytokeratin, CD31, Vimentin and WT1, and negative for CEA, TTF-1, Calretinin, Mesothelial Cell (MC), CD56, CK19, and Hepatocyte. Thus this case is diagnosed as epithelioid angiosarcoma but not malignant mesothelioma. From this case we suggest that carefully reading and understanding of the imaging are a very important clue for appropriate diagnosis. A misdiagnosis may occur on the basis of misunderstanding of tumor localization and a consequent inappropriate immunohistochemical staining programme.

Characterization of Longissimus thoracis, Semitendinosus and Masseter muscles and relationships with technological quality in pigs. 1. Microscopic analysis of muscles.

Three porcine muscles (Longissimus thoracis, Semitendinosus, Masseter), known to have large differences in biochemical and histological traits, were fully characterized and the link between muscle structure and quality evaluated. The oxidative Masseter had more pigment, higher content of metmyoglobin, haem iron, protein and collagen, and was redder with higher fibre numbers, fibre circularity, pH and water holding capacity than the glycolytic Longissimus. Fibre type distribution showed predominance of type IIB in Longissimus and Semitendinosus white, type I in Semitendinosus red and IIA in Masseter. Type I fibres were larger than type IIB and IIA in Semitendinosus and Masseter, respectively, but not in the Longissimus, indicating that fibre size is muscle dependent. Muscle redness was positively correlated with type I fibre traits, haem iron and metmyoglobin, and negatively associated with type II fibre characteristics, non-haem iron and oxymyoglobin. Expressible juice had positive correlation with fibre size and negative with fibre number and connective tissue.

Proteome changes in bovine longissimus thoracis muscle during the first 48 h postmortem: shifts in energy status and myofibrillar stability.

Changes in the insoluble protein fraction of bovine longissimus thoracis muscle from eight Norwegian Red (NRF) dual-purpose young bulls during the first 48 h postmortem were investigated by two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption ionization-time of flight tandem mass spectrometry (MALDI-TOF MS/MS). Significant changes were observed in a total of 35 proteins, and of those, 26 were identified and divided into three different groups: metabolic enzymes, cellular defense/stress proteins, and structural proteins, according to their predicted function. The majority of the metabolic enzymes identified are involved in the energy metabolism of the cell, while the cellular defense/stress proteins can be related to regulation and stabilization of the myofibrillar proteins. Both easily soluble proteins as well as structural proteins were identified in the insoluble protein fraction. We have studied the changes in solubility during postmortem storage by comparing the postmortem changes in protein composition between the soluble and insoluble protein fractions. We have identified two metabolic enzymes (2,3-bisphosphoglycerat mutase and NADH dehydrogenase) and one protein involved in the stress responses/apoptosis of the cell (Hsp70) that have not been identified previously in the insoluble protein fraction. The occurrence of these easily soluble proteins in the insoluble protein fraction could be due to precipitation or aggregation, thereby going from a soluble to an insoluble state.