Melanoma and melanocytic tumors of uncertain malignant potential in children, adolescents and young adults--the Stanford experience 1995-2008.

Pediatric melanoma is difficult to study because of its rarity, possible biological differences in preadolescents compared with adolescents, and challenges of differentiating true melanoma from atypical spitzoid neoplasms. Indeterminant lesions are sometimes designated as melanocytic tumors of uncertain malignant potential (MelTUMPs). We performed a retrospective, single-institution review of melanomas, MelTUMPs and Spitz nevi with atypical features (SNAFs) in patients at 21 years of age and younger from 1995 to 2008. We identified 13 patients with melanoma, seven with MelTUMPs, and five with SNAFs. The median age for melanoma patients was 17 years, 10 for MelTUMPs, and six for SNAFs. Of the 13 melanoma patients, only four were younger than 15 years, while six were adolescents, and three were young adults. Nine melanoma patients (69%) were female. The most common histologic subtype was superficial spreading. The median depth for melanomas was 1.2 mm, and 3.4 mm for MelTUMPs. Microscopic regional nodal involvement detected on elective or sentinel lymph node (SLN) dissection was present in 2/10 (20%) of primary melanomas and 2/6 (33%) of Mel-TUMPs. Complete lymphadenectomy was performed on four melanoma patients, with three positive cases. Patient outcome through March 31, 2009 revealed no in-transit or visceral metastasis in patients with MelTUMPs or SNAFs. One SLN-positive patient (8%) with melanoma developed recurrent lymph node and liver metastasis and died 15 months after primary diagnosis. Our data highlight the rarity, female predominance, and significant rate of SLN positivity of pediatric melanoma. The high rate of MelTUMPs with regional nodal disease reinforces the need for close follow-up.