Incomplete Staining Artifact: A Confounding Frozen Section Pathology Artifact Encountered During Mohs Micrographic Surgery.

The intent of this brief communication is to describe a unique incomplete staining frozen section pathology artifact encountered during Mohs Micrographic Surgery. At the authors’ institution, an amorphous, eosinophilic artifact that obscured cellular architecture was observed multiple times during histological interpretation. It was determined that incomplete tissue staining was likely caused by weak staining, possibly related to an interaction between hematoxylin dye solution and acetone. We adjusted our SLS stain line protocol by adding a 15 second water rinse between the acetone and hematoxylin pots and then compared the old fixation protocol with our new fixation protocol. This artifact, which was regularly found intraoperatively at five separate MMS laboratories has sustainably resolved. Mohs Micrographic Surgery (MMS) is a dermatologic procedure that includes tumor extirpation, tissue grossing, slide preparation, and microscopic histologic interpretation. Tissue grossing and slide preparation are vital components of the MMS procedure. There are many steps throughout tissue processing that can result in frozen section pathology artifacts. Frequently encountered frozen section pathology artifacts include vacuolation of cytoplasm or “freeze artifact,” overstaining and understaining with hematoxylin and eosin, incomplete dehydration, and splaying of collagen in the dermis.1-3 We describe a unique incomplete staining frozen section pathology artifact. J Drugs Dermatol. 2022;21(5):542-544. doi:10.36849/JDD.6722.