Patterns of Immunohistochemistry Utilization in Metastases to the Liver.

Immunohistochemistry (IHC) is a well-established morphology adjunct enabling pathologists to make accurate diagnoses. Metastases to the liver is a common scenario where pathologists may rely heavily on IHC in their interpretation. We conducted this study to audit the patterns of IHC utilization in malignant liver biopsies in 3 practice types (academic, community, and expert) as an initial step toward developing best practice guidelines. A total of 1100 specimens were analyzed and the association between the availability of history of other malignancies and the practice type on IHC utilization was studied. Community pathologists were twice as likely to use IHC and to use more markers per case than academic pathologists or the expert pathologist. When history of another malignancy was available, pathologists were not only 1.5 times more likely to use IHC but they also used more markers per case. IHC was still deemed necessary to reach the diagnosis in 67% of cases with a given history of other malignancy. This study described several variables for consideration in our effort to develop IHC utilization guidelines and its results quantify the variance noted among practice types.