Case 38 - Discussion

Uploaded: 2007-03-31, Updated: 2007-06-22



The tumor cells are positive for vimentin and focally positive for CD34, CD68, Factor XIIIa, and desmin. Keratin, S100, and SMA immunostains are negative.. The histology in conjunction with immunohistochemistry is most consistent with malignant fibrous histiocytoma.


Electron Microscopy:

Ultrastructurally, the tumor consists of spindle cells with irregular cellular borders. The tumor cells have moderate amounts of cytoplasm that is rich in rough endoplasmic reticulum (RER) and mitochondria. Some cells have dense bodies near the plasma membrane. The tumor cells have one large round, oval or irregular nucleus with one or two prominent nucleoli. Multinucleated or multilobe-nucleated cells are identified on some sections. No specific organelles, lysosomes or lipid droplets are present in the cytoplasm of tumor cells.
(Interpretation performed by WJH and ZP. Performed in the Electron Microscopy Laboratory, Creighton Medical Laboratories, Omaha, NE.)
ULTRASTRUCTURAL IMPRESSION: Malignant fibrous histiocytoma.

CYTOGENETICS REPORT (performed at University of Nebraska Medical Center Human Genetics Laboratory, Omaha, NE, report on file):
Cytogenetic analysis revealed the presence of a near-diploid clone characterized by gain of chromosome Y, loss of chromosomes X, 2, 6, 7, 11 and 13, additional unknown material on 1p, 3p, 15q and 17q, a deletion of 2p, and several marker chromosomes. The cp symbol denoted that the karyotype presented is a composite, due to karyotypic heterogeneity, chromosome complexity and morphology within the tumor. Six cell were characterized by a normal male chromosome complement.