Chondroblastomas are unusual cartilage benign lesions of bone that have well-characterized histological features. We reviewed and immunohistochemically examined the paraffin block material of 20 cases, and in seven tumors of this collection we found distinct cytoplasmic muscle-specific actin positivity of some tumor chondroblasts and chondrocytes. Muscle-specific actin-positive cells had the histological and ultrastructural features typical of chondroblasts. Moreover, in their cytoplasm they contained bundles of microfilaments with focal densities, as is typical of myofilaments. We did not observe any basal lamina around these cells, which were surrounded by intercellular matrix of the cartilage tissue type. Therefore, we suppose that muscle-specific actin-positive cells occurring in some chondroblastomas do not represent an admixture of myofibroblasts but chondroblasts with actin expression. The unusual immunophenotype of some chondroblasts might be the result of aberrant actin expression or of the plasticity of their phenotype modulated by microenvironmental stimuli. It is a question of whether, analogously to the terminology of myofibroblasts, such cells could be designated as myochondroblasts.

• MeSH
• aktiny metabolismus   MeSH
• chondroblastom metabolismus   patologie   ultrastruktura   MeSH
• chondrom metabolismus   MeSH
• chondrosarkom metabolismus   MeSH
• chrupavka metabolismus   patologie   ultrastruktura   MeSH
• elektronová mikroskopie MeSH
• fosfopyruváthydratasa metabolismus   MeSH
• imunohistochemie MeSH
• lidé MeSH
• proteiny S100 metabolismus   MeSH
• vimentin metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• fosfopyruváthydratasa MeSH
• proteiny S100 MeSH
• vimentin MeSH

The expression of alpha smooth muscle actin, muscle specific actin, desmin, h-caldesmon, and calponin was studied immunohistochemically in the following soft tissue and bone tumours and tumour-like lesions: muscle fibromatosis, inflammatory pseudotumours, chondroblastoma, enchondroma, chondrosarcoma, fibrous dysplasia, ossifying myositis, osteoblastoma, convential osteosarcoma, leiomyoma and leiomyosarcoma. Tumours and tumour-like lesions with myofibroblastic cells, osteoblasts and chondroblasts frequently exhibited intensive immunoreactivity for the muscle markers, and therefore, some of them may occasionally be confused with leiomyoma and leiomyosarcoma. Calponin does not help to differentiate various mesenchymal tumours expressing muscle markers, because it also stains intensively myofibroblasts, osteoblasts and chondroblasts. We confirmed that h-caldesmon was expressed intensely in leiomyomas and leiomyosarcomas, and never in the other tumours examined, with the exception of three chondroblastomas. The results have shown that h-caldesmon is a rather specific and sensitive marker for smooth muscle tumours, but it can also stain some actin positive myochondroblasts. It is possible that the positivity of h-caldesmon in some chondroblastomas is due to their complete myogenic transdifferentiation, and so we use the term myochondroblasts and myochondrocytes for designation of such S-100 protein, actin, and h-caldesmon positive cells.

• MeSH
• aktiny analýza   MeSH
• calponiny MeSH
• desmin analýza   MeSH
• diferenciální diagnóza MeSH
• imunohistochemie MeSH
• lidé MeSH
• mezenchymom chemie   diagnóza   MeSH
• mikrofilamentové proteiny MeSH
• nádorové biomarkery analýza   MeSH
• nádory kostí chemie   diagnóza   MeSH
• nádory měkkých tkání chemie   diagnóza   MeSH
• nádory ze svalové tkáně chemie   diagnóza   MeSH
• proteiny vázající kalmodulin analýza   MeSH
• proteiny vázající vápník analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• desmin MeSH
• mikrofilamentové proteiny MeSH
• nádorové biomarkery MeSH
• proteiny vázající kalmodulin MeSH
• proteiny vázající vápník MeSH