By John Otrompke
CHICAGO -- November 10, 2009 -- Because it can be very difficult to distinguish liver metastases of adenocarcinoma from cancer cells which are native to the liver under a microscope, pathologists should use 4 immunocytochemical panels, including a newly researched protein called glypican, in combination with cytomorphology to make the crucial distinction, according to a study presented here at the American Society for Clinical Pathology (ASCP) 2009 Annual Meeting.
"When they are poorly-differentiated, these 2 types of cancer cells become difficult to distinguish, but clinically it is very important to tell if the patient has liver cancer or metastatic cancer from the lung or breast, because the 2 diseases require a totally different treatment and management approach," said Husain Saleh, MD, Department of Pathology, Wayne State University School of Medicine, and Sinai Grace Hospital, Detroit, Michigan, on November 3.
For the trial, researchers performed 7 immunocytochemical stains on 42 cases of liver cancer and 48 cases of metastatic adenocarcinoma. Of the liver cancer cases, 38 of 42 tumours were correctly identified by a panel of 4 markers with an accuracy rate of 90.5%. The same panel correctly identified 44 of 48 of the metastatic cancer cells, with an accuracy rate of 91.7%.
The 4 tests were for HepPar 1, an antigen present in the embryo; MOC 31, a compound present on the surface of the cell, which reacts only with epithelial cancer, not other forms of cancers; CK7, which functions like a skeleton of a cell; and glypican, a marker the utility of which was only discovered within the past year and a half, according to Dr. Saleh.
The panel of 4 tests should be used in conjunction with traditional cytomorphology to distinguish the cells. While the use of standard observation is tricky, there are clues that a trained pathologist can look for, said Dr. Saleh.
"There are clues and hints to suggest one or the other," he said. "For example, in hepatocellular carcinoma, which starts in the liver, the cells have prominent pleomorphism, such as the variable size and shape of the nucleus. Another thing they have is macronucleoli, within the nucleus, because these in the liver can be really big." Other features of liver cancer include intranuclear inclusions and naked nuclei, Dr. Saleh added.
"On the other hand, adenocarcinoma can have some unique features including vacuolated columnar cytoplasm, cytoplasmic inclusions, and eccentric nuclei," he explained.
[Presentation title: Discriminating Hepatocellular Carcinoma From Metastatic Adenocarcinoma on Fine-Needle Aspiration Biopsy of the Liver: The Utility of Immunocytochemical Panels. Abstract 47]
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