SPITZ NEVUS VERSUS MELANOMA ------------------------------------------------------- When pathologists from different institutions disagree on a pigmented lesion diagnosis, who would be a good "third opinion" to send the lesion to? A new patient came to me for follow up of a malignant melanoma removed by another dermatologist by wide excision several years ago . After reading the pathology report I thought the diagnosis was suspect, and sent the slide off to a dermatopatholgist . He diagnosed Spitz Nevus. The patient and our medical director would like a third, expert , opinion. As I have grown to value the opinions of this discussion group, I would appreciate names of some of your respected dermpath consultants. Please email me directly unless you feel all would benefit by further discussion of the issue. Diane Thaler ------------ In regard to the patient whose melanoma/Spitz was widely excised. I recall an article in the Jaad about 10 or 12 years ago in which there was a late follow up of a series of well respected dermatopathologists (Ackerman, Clark, Mihm,etc. diagnosed cases of Spitz tumor and a significant number of these turned up as metastatic deposits (same pattern as the original "Spitz") in the brain and elsewhere! I don't necessarily think of that kind of excision as poor prac tice especially in anyone over 15 years of age. For that reason I would not be any too critical in that kind of case! For what it is worth! Pat Condry ----------- A recent post regarding additional consultation for a pigmented lesion diagnosed as either melanoma or spitz nevus has me thinking. There are two issues here: 1: If there are two interpretations of a pigmented lesion, is one correct and the other wrong? Which obvserver is right? Consider the following, recently published in a general pathology journal by Evan Farmer, M.D. Eight premeir dermatopathologists, chosen on the basis of reputation and publications each submitted five cases of pigmented lesions. The cases were selected as difficult, but "classic"; cases that might be included in a publication on a given pigmented process (e.g. Spitz vs. melanoma). All eight dermatopatologists interpreted each case and gave a classification of Benign, indeterminant or malignant. Interobserver variability measured by kappa was approximately .5 ("moderate" agreement). Reviewing the table included shows that on at least 8 cases, interpretation was evenly split between a benign and a malignant diagnosis. many more cases had at least two discordant interpretations. Remember that these cases were selected as "classic", and were interpreted by the cream of the crop. 2: When faced with several diagnoses, what is the proper course of action? Clinicians must understand that the pathology of pigmented lesions is an attempt to predict the biological behavior of a neoplasm based on static histologic images. It should be clear that the only feature of a neoplasm diagnostic of malignancy is the presence of metastasis. Histologic criteria are abstracted retrospectively from cases with known outcome. Specifically in the case of melanoma, criteria predictive of malignancy were developed from advanced lesions. With the trend toward diagnosis of thinner, earlier lesions, these criteria may not be fully developed. Unfortunately, the criteria for the diagnosis of melanoma are not standardized, and are certainly not consistently applied. When two experts disagree, there is no right answer except in the case of subsequent metastasis. When faced with different interpretations of a difficault neoplasm, there is a tendancy to request another interpretation from a pathologist with high credibility. The best approach is to treat the process as the worst case senario. There is the possibility of overtreatment of a Spitz nevus. However, this does not violate community standard of practice and does not represent malpractice. Paul S. Gillum -------------- Paul, I agree with you. We recently had a case where our dermatopathologist thought a pigmented lesion was benign; our general pathologist, who was responsible for reading the surgical specimens thought it was malignant. The AFIP and one dermatopathologist consultant thought it was malignant; another dermatopathologist consultant thought it was benign. I recommended excisional treatment for melanoma, but the patient was thoroughly confused by all these consultations, went off to see another dermatologist, bearing his slides, and I don't know the outcome. In retrospect, we should have just excised it. Yelva Lynfield --------------