Differentiating small round cell sarcomas of the soft parts by an innovative immunogold labeling method: an ultrastructural study

Role of electron microscopy in the evaluation of soft tissue neoplasms, with emphasis on spindle cell and pleomorphic tumors

The current significant role of transmission electron microscopy in the evaluation of soft tissue tumors when correlated with conventional histological and immunohistochemical studies is discussed for the following entities: myxofibrosarcoma, storiform-pleomorphic fibrosarcoma (malignant fibrous histiocytoma), and myofibrosarcoma; dermatofibrosarcoma protuberans; hemangiopericytoma; monophasic synovial sarcoma; extrarenal rhabdoid tumor; soft tissue perineurioma; and gastrointestinal stromal tumors, notably the so-called autonomic nerve variant.

Subcellular localization of Bcl-2 protein in synovial sarcoma

The subcellular localization of Bcl-2 protein in surgically resected, fixed-frozen tissue specimens of seven tumors from six cases of synovial sarcoma and a synovial sarcoma cell line was examined using laser-scanning confocal microscopy and immunoelectron microscopy. Bcl-2 protein in synovial sarcoma cells was detected in the nuclear envelope, endoplasmic reticulum membrane, and mitochondrial circumference. Based on the finding of pre-embedding immunoelectron-microscopy observation, the distribution of Bcl-2 protein in such membranous organella was patchy. A computer-based image analysis failed to reveal any quantitative differences between the inner and the outer mitochondrial membranes. The tumorigenesis of synovial sarcoma is also discussed from the viewpoint of Bcl-2 overexpression.