The evaluation of post-surgical processing on the measurement of cutaneous and myocutaneous biopsy specimen dimension in cats

Abstract

The purpose of this study was to determine if post surgical processing affected the dimensions of skin samples obtained from cats. A second objective was to identify factors that contributed to changes in the dimensions of tissue obtained from normal cats that underwent routine histological processing. Cutaneous and Myocutaneous samples were obtained from twelve normal cats at three locations, the neck, thorax and tibia. Dimensional measurements of the samples were taken at five time points by a single observer. The time points included prior to excision, after excision, after margins were inked, 36 hours after fixation in formaldehyde and after completion of histological processing and hemotoxylin and eosin staining. The measurements at each time point were compared to original measurements at the first time point. Tissue samples decreased in lateral margins and increased in depth at the final time point. The average shrinkage in the lateral dimensions was 35% and the increase in depth was 55%. The tibia exhibited the greatest shrinkage and the neck exhibited the least shrinkage. Inclusion of the underlying muscle did not affect the degree of change in dimension of the specimen. In the present study, each element from excision to formalin fixation and histopathological processing induced changes in tissue dimension manifest principally as shrinkage in the lateral margins and an expansion of the depth. Shrinkage should be a consideration when interpreting surgical margins in clinical cases. Further investigation of this phenomenon in a wider feline population in clinical cases is warranted to classify the degree of change in dimensions of specimens and to identify other variables that affect the degree of tissue shrinkage.