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Juvenile Melanoma (Spitz melanocytoma and progressive neoplastic variants - Spitz “nevus” in another guise as structured in a different system of logic):
Juvenile melanoma, as a variant of MDM, is intermediate neoplasia; in contrast to the common premalignant dysplasias and common melanomas, it is defined as an independent neoplastic system without a clearly defined benign precursor. It exists as a neoplasm of a qualified type, one which has a low propensity for metastasis. It is a neoplasm for which nodal metastasis may not carry the same prognostic import as it would for common melanoma. The system of logic which relates to classical Spitz “nevus” has been set aside; it was based on a system of logic in which the functions and values of its “truth table” are of questionable prognostic significance; the questionable truth tables were a reflection of the influence of an assigned designation on the conceptualization of the lesion; to characterize lesions in this category as some type of nevus is obsfucatingly incorrect.
In this new system of logic, there are prognostic indicators but, currently, they are of questionable value in selecting lesions which are prone to manifest aggressive behavior. It would seem to be a mistake to divide the broad category on the basis of histologic and cytologic “grade.” To do so would be an open invitation to surgeons and oncologists to assume that high grade lesions are true melanomas, and require aggressive treatment. The designation, grade, is as loaded with implications as is the designation, “spitzoid melanoma.” I would suggest that lesions with few troublesome features be characterized as “step 1 type,” and those with troublesome features be characterized as “step 2 type.” In this approach, step 2 type lesions would be appreciated as a higher stage of neoplasia, but would also be appreciated as something different from common melanoma. This essentially was, and is, the approach in the concept of MDM. Perhaps, there should be a step 3 type in which atypia and patterns are more deviant (see /spectrumspitz.html, c5t3P5-7)
Currently, sentinel lymph node biopsy is being encouraged for step 2 type lesions. Unfortunately, a positive lymph node is then assumed to be the prognostic equivalent of a positive lymph node from a common melanoma; the assumption is that progressive disease is likely; the patient is likely to be subjected to aggressive treatment, including treatment with interferon. In light of the many questions regarding the behavior of Spitz-like variants, this approach is presumptuous.
The system of logic, proposed herein for a redefinition of juvenile melanoma, supplants that system which would promote the concept of “one melanoma, histologically and biologically.”
In fig. c25t3P2, a diagramatic representation of the domain of intermediate neoplasia is presented. In this modification, physical dimensions do not have the same relevance as they do for the common melanomas.
If atypical pigmented spindle cell nevus is evaluated by the same criteria as the “Spitz”variant, there are good reasons to include this process in the category of intermediate neoplasia. I suppose the lesion might be characterized as intermediate melanocytic neoplasia of Reed type (pigmented spindle cell variant, melanocytic neoplasia of indeterminate malignant potential).
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