Multitumor "sausage" blocks in immunohistochemistry. Simplified method of preparation, practical uses, and roles in quality assurance.

This report describes a simplified method for preparing multitumor sausage blocks (MTSBs) for use in immunohistochemical procedures. Rather than relying on previously processed paraffin blocks as a source of material, this procedure involves procuring tissue at the time of gross specimen examination. The tissue is processed along with routine surgical pathologic material, and the paraffinized samples are placed in "storage cassettes" for easy cataloging and storage. Thin strips are cut from the tissue in the "storage cassettes" and combined by dripping liquid paraffin onto them while they are rolled between the thumbs and forefingers, somewhat like making a cigarette. This results in a tissue "log." Transverse sections of the "log" are embedded in paraffin blocks and used as MTSBs. Practical uses of MTSBs are discussed, and their role in quality assurance is stressed.