Utility of additional tissue sections in dermatopathology: diagnostic, clinical and financial implications

As histopathologic assessment is subject to sampling error, some institutions 'preorder' deeper sections on some or all cases (hereafter referred to as prospective deeper sections), while others order additional sections only when needed (hereafter referred to as retrospective deeper sections). We investigated how often additional sections changed a diagnosis and/or clinical management. Given the recent decrease in reimbursement for CPT-code 88305, we also considered the financial implications of ordering additional sections.

Cases (n = 204) were assigned a preliminary diagnosis, based on review of the initial slide, and a final diagnosis, after reviewing additional sections. Cases with discordant diagnoses were assessed by two dermatologists, who indicated whether the change in diagnosis altered clinical management. Expenses were estimated for three scenarios: (a) no additional sections, (b) prospective deeper sections and (c) retrospective deeper sections.

Diagnoses were modified in 9% of cases, which changed clinical management in 56% of these cases. Lesions obtained by punch-biopsy and inflammatory lesions were disproportionately overrepresented amongst cases with changed diagnoses (p < 0.001, p = 0.12, respectively). The cost of prospective deeper sections and retrospective deeper sections represented a 56% and 115% increase over base costs, respectively. Labor costs, particularly the cost of dermatopathologist evaluation, were the most significant cost-drivers.

While additional sections improve diagnostic accuracy, they delay turn-around-time and increase expenditures. In our practice, prospective deeper sections are cost effective, however, this may vary by institution.