BOCA RATON, FLA. – Pigmented Spitz nevi, and even atypical Spitzoid melanocytic tumors, are unlikely to be melanoma in children.
"Boy, does this create controversy," noted Dr. Seth J. Orlow at the meeting of the Florida Society of Dermatology and Dermatologic Surgery.
Dr. Seth J. Orlow
Pigmented Spitz nevi and atypical Spitzoid melanocytic tumors (ASMT) can appear suddenly and grow rapidly in children. Part of the problem is that these lesions have been shown to be associated with microscopic foci in draining lymph nodes in children who have been subjected to sentinel lymph node biopsy.
In some cases, this has been used as a basis for a diagnosis of melanoma.
"It turns logic upside down, but it's no proof of anything – only that the child has Spitz nevus," said Dr. Orlow, chair of dermatology and the Samuel Weinberg professor of pediatric dermatology at New York University.
Spitz nevi are common, and typically appear as pink-red papules on the face that are less than 1 cm in diameter. However, they can also develop as pigmented lesions, particularly on the limbs.
Although a pigmented lesion in a child is likely a Spitz nevus, the dermatoscope is particularly helpful for confirming the diagnosis, as Spitz nevi have a very characteristic starburst or peripheral globule appearance.
"This is one of those examples where having a dermatoscope really changes things I do," Dr. Orlow said, explaining that although he tends to assume that a pigmented lesion in a child is a Spitz nevus, seeing the typical pattern that is diagnostic of a Spitz nevus is reassuring for both him and the patient’s parents.
Even with ASMT (a subset of Spitzlike growths with features such as mitoses that are associated with melanoma), the risk of melanoma is minimal, he noted.
Although interobserver agreement on diagnosis and prognosis is poor with these lesions, data show that the prognosis is favorable in patients both with and without positive lymph nodes. In one recent study of 11 children with ASMT and positive lymph nodes, all remained disease free at an average of 47 months’ follow-up. By comparison, two of five children younger than age 18 years with histologically unambiguous melanoma and positive sentinel lymph nodes died from metastatic melanoma (Am. J. Surg. Pathol. 2009;33:1386-95).
This finding is not surprising, because these are not melanomas, Dr. Orlow said.
What are pediatric dermatologists' attitudes about Spitz nevi and ASMTs?
Findings from a recent Web-based survey of 350 pediatric dermatologists conducted by Dr. Orlow and his associates showed that academic pediatric dermatologists are most comfortable following Spitz nevi clinically, and are more likely to do so than are those in private practice. It also showed that both never seeing an unambiguous melanoma in a child and believing that Spitz nevi are not precursors to melanoma are – not unexpectedly – predictors of following patients clinically, Dr. Orlow said.
Also, clinicians observe both involution and evolution of Spitz nevi to more banal nevus subtypes as evidence of their benign nature, he said.
Of all those surveyed, only two (who were in private practice) had reported that a death resulting from melanoma had occurred in a patient of theirs.
"Not a single pediatric dermatologist at any academic medical center had ever seen a death from an atypical Spitz nevus in their entire career" he concluded.
Dr. Orlow had no disclosures relevant to his presentation.