Rhabdomyosarcoma with Pseudolipoblasts Arising in Ovarian Carcinosarcoma: A Distinctive Postchemotherapy Morphologic Variant Mimicking Pleomorphic Liposarcoma
Figure 1
(a) Histologically, there was almost complete effacement of the ovary by a malignant neoplasm with two components. The smaller component, shown here, is composed of trabeculae of markedly atypical epithelial cells, consistent with high grade serous adenocarcinoma. (b) Poorly differentiated carcinoma is seen to abut the predominant sarcomatous component, much of which is composed of sheets of pleomorphic multivacuolated cells. ((c)-(d)) There are extensive sheets of large polygonal cells containing abundant multivacuolated cytoplasm with small hyperchromatic nuclei with prominent nuclear indentations, morphologically suggestive of pleomorphic lipoblasts. (e) Admixed in areas with the vacuolated cells are moderately and markedly pleomorphic ovoid, spindle, and polygonal cells with atypical hyperchromatic nuclei and moderate to abundant amounts of eosinophilic cytoplasm. This appears to represent a transition zone, between more typical rhabdomyoblasts showing cytodifferentiation and the unusual multivacuolated pleomorphic lipoblast-like rhabdomyoblasts. (f) At high power, cytoplasmic cross striations are seen focally within the intermediate cells.
