We were pleased to see the report by Dyson et al,1 which was similar to our 1983 work2 and reached the same conclusions. In short, when additional histologic sections of a melanoma specimen beyond those assessed originally are examined, the determined depth will be greater and more poor prognostic findings will be reported.
As we implied in our original article, this result can be anticipated. Let us assume that the diagnosis of melanoma and the attendant prognostic factors are determined from 2 single sections (ie, slices) of the skin specimen that is delivered to the dermatopathologist. If, for example, 10 more sections are obtained, the chances increase that the measured depth will be greater. It certainly cannot be less, because the measured depth is not an average, it is the maximum depth. Any lesser depths in the new sections are ignored, and any greater depths are recorded until a new maximum is found. Similarly, if ulceration was not observed in the original sections, the possibility that ulceration (if it exists) will be found increases with further examination of the specimen. Indeed, in 3 cases reported by Dyson and colleagues,1 additional sectioning of the specimens revealed previously undetected ulceration. Again, the examination of additional sections results in worsening of the prognosis and never in an improvement in the prognosis.