Diagnosis:

Spitz tumour of uncertain malignant potential (STUMP), regarded by some as spitzoid melanoma.

Comments:

This is another slide of the lesion, shown and discussed in the slide set of Spitz naevus (Case 1A and 1B). Since there is much controversy regarding the appropriate terminology of such deeply invasive and nodular spitzoid tumours in prepubertal children, it is also included here. 

STUMP WITH DEEP NODULAR COMPONENT IN CHILDREN

Some Spitzoid melanocytic proliferations of prepubertal children present with deep, miotitcally active nodules that bulge into the deep dermis or even subcutis. Spread to regional lymph nodes is seen repeatedly, and to those who regard spread to a regional node as formal proof of malignancy, this means that these lesions are malignant, i.e., (spitzoid) melanomas. Ohers have pointed out that children with such tumors and nodal deposits do remarkably well, and that distant metastasis appears to be very rare, much rare than one would expect in case of thick melanoma NOS with a positive regional lymh node.

For te time being, I regard these lesions as STUMP (Spitz tumor of uncertain malignant potential). Hopefully, future work and clinical experience will shed more light on this issue.

REFERENCES:

• Mones JM, Ackerman AB. "Atypical" Spitz's nevus, "malignant" Spitz's nevus, and "metastasizing" Spitz's nevus: a critique in historical perspective of three concepts flawed fatally. Am J Dermatopathol. 2004 Aug;26(4):310-33.
• Mones JM, Ackerman AB. Melanomas in prepubescent children: review comprehensively, critique historically, criteria diagnostically, and course biologically. Am J Dermatopathol. 2003 Jun;25(3):223-38.
• Mooi WJ, Krausz T. Spitz nevus versus spitzoid melanoma: diagnostic difficulties, conceptual controversies. Adv Anat Pathol. 2006 Jul;13(4):147-56.
• Ackerman AB, Mones JM. Rudimentary/elementary. Adv Anat Pathol. 2007 Mar;14(2):143-4; author reply 144-5.