Figure 23.

Technical artifacts. Effects of drying. (a): surfactant apoprotein immunostaining for the skins, contamination of cytokeratin-positive scales. (b): cytokeratin immunostaining for spindle cell sarcoma and insufficient deparaffinization (c): smooth muscle actin immunostaining for leiomyosarcoma. Drying of sections during antibody incubation causes nonspecific binding in the dried area (a). Contaminated cytokeratin-positive scales on the section should be distinguished from true positivity (b). False-negative rounded areas result from insufficient deparaffinization. (c).