Biopsy Interpretation of Soft Tissue Tumors by Cyril Fisher Elizabeth Montgomery Khin Thway

Author:Cyril Fisher,Elizabeth Montgomery,Khin Thway
Language: eng
Format: epub
ISBN: 9781451192995
Publisher: Lippincott Williams & Wilkins
Published: 2015-08-05T16:00:00+00:00

The lipoblasts are immunoreactive for S100 protein. SMA, desmin, and cytokeratin can occasionally be positive in the pleomorphic background cells. In the epithelioid variant, focal immunoreactivity for cytokeratins (20%), melan-A (67%), or S100 protein (55%),38,39 the former two enhancing the resemblance to metastatic adrenal cortical carcinoma, and the latter two suggesting metastatic melanoma. Inhibin is negative. As always, careful microscopic observation and consideration of the clinical picture can prevent a diagnostic error based on immunohistochemical findings. Pleomorphic liposarcomas are cytogenetically heterogeneous and do not have specific findings. Some pleomorphic liposarcomas and myxofibrosarcomas share genomic imbalances,40 and array-based comparative genomic hybridization has shown that pleomorphic leiomyosarcoma and dedifferentiated liposarcoma are clearly separated by the genomic profiles.41 An example of epithelioid pleomorphic liposarcoma has been found to have FUS-CHOP (DDIT3) transcripts,42 which are normally a feature of myxoid-round cell liposarcoma.

PLEOMORPHIC LEIOMYOSARCOMA

The diagnosis of leiomyosarcoma is discussed in Chapter 6. Pleomorphic leiomyosarcoma has been defined as a pleomorphic undifferentiated sarcoma in which less than one-third of the tumor shows smooth muscle differentiation with fascicular architecture (e-Fig. 13.36). In pleomorphic leiomyosarcoma, there is generally expression of the three muscle antigens (SMA, desmin, and h-caldesmon) in the pleomorphic areas but in fewer cells than in the fascicular component. Many other pleomorphic sarcomas also demonstrate focal expression of SMA and desmin (although rarely h-caldesmon), but this is insufficient for a diagnosis of leiomyosarcoma in the absence of the appropriate morphologic features. However, as noted above, this affects prognosis, and such tumors should be reported as pleomorphic sarcomas with immunohistochemical evidence of myoid differentiation.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.