Which tissue would not fix well on the above schedule?

• A. Excisional breast
• B. Esophageal biopsy
• C. Placenta
• D. Muscle biopsy

Answer: (A)

Fixation relies on the fixative reaching every part of the tissue quickly and evenly. Large, bulky specimens—especially fatty breast tissue from an excisional procedure—pose a penetration challenge. On a standard fixation schedule designed for small biopsies, formalin may struggle to diffuse to the center of a thick breast specimen, leaving the interior underfixed and poorly preserved. To ensure uniform fixation, such large pieces should be cut into thin slices or smaller blocks so the fixative can permeate all parts effectively. The other tissues mentioned are typically handled as smaller pieces where standard fixation times and volumes work well, so they fix more reliably on the same schedule.