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Epithelioid leiomyosarcoma of the external deep soft tissue
Tetsuji Yamamoto1, Rieko Minami, Chiho Ohbayashi
1Department of Orthopaedic Surgery, Kobe University School of Medicine, Kobe, Japan. yamatetu@med.kobe-u.ac.jp
Archives of Pathology & Laboratory Medicine
|March 20, 2002
Summary
Epithelioid leiomyosarcoma is rare in deep soft tissues. This case report details a thigh muscle tumor in an elderly man, highlighting its unique presentation and immunohistochemical profile.
Area of Science:
- Oncology
- Pathology
- Skeletal Muscle Tumors
Background:
- Epithelioid leiomyosarcoma (ELMS) is a rare soft tissue sarcoma.
- ELMS predominantly occurs in the uterus, with extragenital locations being exceptionally uncommon.
- Deep soft tissue ELMS is particularly rare, posing diagnostic challenges.
Observation:
- A case of epithelioid leiomyosarcoma is presented in the thigh muscle of a 78-year-old male patient.
- Histological examination revealed a tumor composed mainly of round/polygonal cells in sheets, with a minor spindle cell component.
- Immunohistochemical analysis showed positivity for vimentin, alpha-smooth muscle actin, and alpha-sarcomeric actin.
Findings:
- The tumor cells were negative for a broad panel of markers including desmin, S100, GFAP, keratins, EMA, CAM 5.2, HMB-45, LCA, Factor VIII, and CD34.
- Electron microscopy confirmed the presence of abundant actin-type filaments within the cytoplasm of some tumor cells.
- These findings support the diagnosis of epithelioid leiomyosarcoma of soft tissue.
Implications:
- This case expands the known anatomical sites for epithelioid leiomyosarcoma.
- Accurate diagnosis relies on a combination of histology, immunohistochemistry, and potentially electron microscopy.
- Understanding the immunophenotype is crucial for differentiating ELMS from other neoplasms.