These bile ducts are not present deeper in the tumor nor within metastases and are considered to represent entrapped or residual bile ducts rather than neoplastic elements of the tumor. Multinucleated cells with hyperchromatic nuclei are frequently scattered throughout the lesion. Chou and colleagues found the globules to be electron-dense material bound by a membrane and suggested they were liposomal in origin. The globules fail to stain with a variety of immunohistochemical antibodies. Hyalinized collagen may be present in dense bundles and foci of hematopoiesis may be seen in the stroma.
Mitosis are frequently present and occasionally bizarre.
These cells may resemble fibroblastic, histiocytoid, fibrohistiocytoid and myofibroblastic cells occasionally suggesting a malignant fibrous histiocytoma, a tumor reported only in the liver of adults. Immunohistochemical staining in UES No. 0 Chou and colleagues reported an aneuploid DNA stemline with high proliferative S phase in two cases studied with flow cytometry. They suggest that acquired drug resistance as seen in their patient may correlate with overexpression of the mdr1 gene. Harris MB, Shen S, Weiner MA, et al.