myelin-basic-protein and Soft-Tissue-Neoplasms

Malignant peripheral nerve sheath tumors arise from Schwann cells or within existing neurofibromas and have a strong association with type 1 neurofibromatosis. These tumors are histologically diverse and may contain malignant areas of divergent mesenchymal differentiation, the most common of which is skeletal muscle (rhabdomyosarcoma). Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation is also known as malignant triton tumor. Malignant triton tumor has a worse prognosis than classic malignant peripheral nerve sheath tumor does, and the correct diagnosis requires attention to the clinical history and knowledge of the complexities regarding its differential diagnosis. In this review we discuss the clinical, histopathological, immunohistochemical, and prognostic features of this rare neoplasm.

Topics: Biomarkers, Tumor; CD57 Antigens; Humans; Immunohistochemistry; Myelin Basic Protein; Nerve Sheath Neoplasms; Rhabdomyosarcoma; S100 Proteins; Soft Tissue Neoplasms

Immunohistochemical localization of tissue specific or cell-specific antigenic markers in neoplastic cells has become an increasingly important tool in the pathologic diagnosis of tumors. The myelin-specific proteins of peripheral nervous system myelin, because they are normally synthesized in Schwann cells, are potentially useful markers for neoplasms arising from peripheral nerves. The authors carried out immunohistochemical studies on 18 cases of Schwann cell neoplasms, including schwannomas, neurofibromas, and granular cell tumors, to determine whether two myelin-specific proteins, myelin basic protein and P2 protein, were present in neoplastic Schwann cells. None of these tumors showed immunostaining for either myelin basic protein or P2 protein in neoplastic cells. In contrast, S-100 protein, which is a well established marker for normal and neoplastic Schwann cells, was localized by immunohistochemistry to neoplastic cells in all 18 neoplasms. Therefore, although myelin basic protein and P2 protein are known to be Schwann-cell-specific proteins, they do not appear to be expressed commonly in neoplastic Schwann cells.

Topics: Histocytochemistry; Humans; Immunologic Techniques; Myelin Basic Protein; Myelin P2 Protein; Neoplasms, Muscle Tissue; Neurilemmoma; Neurofibroma; S100 Proteins; Schwann Cells; Skin Neoplasms; Soft Tissue Neoplasms

To date, the histogenesis of alveolar soft part sarcoma has been considered to be of paraganglioma origin, striated muscle cell origin, or as a malignant granular cell myoblastoma, neural neoplasm, or renin-producing tumor. Further studies for these existing theories were performed based on various methods. The negative formaldehyde-induced fluorescence and the immunohistochemical absence of neuron-specific enolase were against the paraganglioma theory. The immunohistochemical absence of myelin proteins (P2 protein and PO protein) and S-100 protein were against the malignant granular cell myoblastoma and neural neoplasm theory. Furthermore, there was a totally negative immunohistochemical finding for renin in the tumor cells, and the biochemical relationship of the tumor and renin was completely negated. The contradiction in a well-known report that the components of crystals were considered to be Z-band materials such as tropomyosin was referred to based on recent myological data. Concurrently, the absence of tropomyosin was immunohistochemically demonstrated. Hence, the issues on the histogenesis of alveolar soft part sarcoma and the identity of the characteristic crystalloids remain open for discussion.

Topics: Adult; Humans; Immunoenzyme Techniques; Male; Microscopy, Electron; Myelin Basic Protein; Myelin P0 Protein; Myelin P2 Protein; Myelin Proteins; Phosphopyruvate Hydratase; Renin; S100 Proteins; Sarcoma; Soft Tissue Neoplasms; Tropomyosin