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Dr. Mark Hurt's Blog

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How much should we push clinicians for molecular testing of melanocytic lesions?

Mark A. Hurt MD


In my practice, I and my colleagues confront a problem almost on a weekly basis. I'm sure many of you confront the same problem. It happens this way: there is an unusual melanocytic lesion that presents the differential diagnosis of melanoma [i]versus[/i] melanocytic nevus, but there is enough similarity of the lesion to a melanocytic nevus, and there is enough depth (often 1 mm or more), that if the lesion is melanoma, most dermatologists (at least in the USA) will pursue a sentinel lymph node biopsy.

This is not a small matter, not only because of the anxiety that results in “not knowing” but also in the costs involved in obtaining aCGH or FISH, which can amount to ~$1,500. I have explained, on a number of occasions to clinicians and to patients, that the stated sensitivity is about 80%, which means a positive result will be found in 80% of melanomas, but 20% of melanomas are negative. Thus a negative result does [i]not[/i] exclude melanoma in such lesions. Most patients want to proceed even with only 80% sensitivity, as a positive result will classify the lesion definitively as melanoma, and a treatment plan can thus be enacted.

In the last few years, since these molecular evaluations have gone “live,” I have pushed clinicians to obtain molecular information on patients’ melanocytic lesions when conventional histopathology and immunohistochemistry cannot resolve the diagnosis. Most have complied, despite the expense involved, given the stakes.

Recently, a clinician informed us that he was upset that we were providing such options in writing in reports when these lesions are identified (full disclosure: we do not perform aCGH or FISH in our lab; we refer these cases to trusted and experienced consultants -- so we have no financial stake in the matter).

So, here are my questions to you, the reader:

1. How do you approach this problem?
2. Do you suggest that molecular analysis might be useful to establish a definitive diagnosis?
3. What do you write in reports?
4. What do you tell clinicians, if anything, over the telephone?

I very much want to know your experience.


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