Melanoma in Children Martin C. Mihm Jr., M.D.

Transcription

1 Melanoma in Children Martin C. Mihm Jr., M.D. The concept of melanoma in the young will be reviewed based on a study from the Pigmented Lesion Clinic at the Massachusetts General Hospital (Livestro DP et al, Cancer.2007; 110: ). Patients less than twenty years of age account for 1.3 and 2% of all melanomas, whereas, in prepubertal children, the tumors comprise only % of newly diagnosed malignant melanomas in the young. The literature exhibits a range of age with cut-off for pediatric melanoma anywhere from ten to twenty-one years. Therefore, we chose less than twenty years of age as our cutoff. In the period of , 73 patients fell into this category at the Massachusetts General Hospital. We contrasted these patients with two adult control groups with melanoma; specifically, 146 case matched controls were reviewed. A separate comparison was made with those thirteen years or less matched against case matched adult controls as well. The two groups had similar demographics in clinical presentation. However, the melanoma history was different in some aspects, for example, thirty-three percent of prepubertal melanomas arose from giant congenital nevi. Fifty percent of the cases that arose in the nevus setting accounted for occurred during the first decade of life. Otherwise, as for the types of melanoma, the distribution was similar except there were no cases of lentigo maligna melanoma. No children with xeroderma pigmentosum were included. The problems of borderline tumors and so-called MELTUMPs were also. The controls were matched according to year of diagnosis as the patients were accumulated over thirty-two years. Elective regional lymph node dissection was performed before 1933; afterward sentinel node biopsies were performed. In order to have greater power in the analysis, two adult patients were matched for each pediatric patient. With this study it was not possible to review all slides of young melanoma patients. In thirteen patients, there was no thickness known for the primary tumor and the slides were not available. Ten of these thirteen patients were diagnosed before 1990.

2 Of the eight patients, who were diagnosed at an age less than thirteen years, three had tumors arising in congenital nevi. Of the sixty-five patients that were greater than thirteen years of age, eight (12.3%) had congenital nevi as precursors. Seventeen had a nevus not further defined. Dysplastic nevi were more commonly noted clinically in patients less than thirteen years of age. A family history was more common than in the adult patients (25.6% versus 17.3% respectively). Of the different types of malignant melanoma, superficial spreading was the most common (61%), 34.2% has ulceration compared to 48.6%. Median thickness was 1.3 millimeters in patients less twenty years of age and 0.9 in those greater than twenty years of age. Nine children had a mean tumor thickness of 3.8 millimeters. No other significances were found as far as lymph node evaluation is concerned. Until 1993, elective regional lymph nodes were performed, after sentinel biopsies were performed. All children who had positive sentinel node biopsies underwent completion with a lymphadenectomy. Eleven of twenty-five patients, less than twenty years of age had 44% had positive lymph nodes in the pediatric group compared to eleven of forty-six adult patients (23.9%). Young patients with melanoma, in this study, had more significantly metastatic melanoma identified in elective node dissections although the incidence (17.8%) of positive lymph nodes at initial presentation in young patients with melanoma was higher than the 9.6% found in adult patients. The sample size was small and statistical significance was not reached. Of forty-nine young patients with melanoma with tumors in the AJCC T1 or T2 stage, eight patients (16%) underwent initial lymph node surgery but none had positive lymph nodes. On the other hand, Twenty-four patients of the young group had AJCC T3 or T4 tumors and nineteen of these patients underwent initial lymph node surgery. Thirteen of these patients (68.4%) had positive lymph nodes including two patients who presented with clinically enlarged nodes. Two patients with positive lymph nodes were age ten years at the time of diagnosis, all others were age fifteen years or greater.

3 Of the sixteen young patients who underwent sentinel lymph node biopsy, the mean tumor thickness was 2.8 millimeters for patients less than thirteen years of age, and 2.7 millimeters for patients greater than thirteen years of age. Ulceration was absent in the negative nodes of the prepubertal children but was positive in two of the six patients, 13 years or older who had negative nodes. The high risk for positive sentinel nodes observed in the group below fifteen years of age, the median tumor thickness was 2.8 millimeters in those patients who underwent lymphatic mapping. All young patients who had sentinel lymph nodes had either AJCC, T3 or T4 primary lesions. Three of the five patients were classified as minimal deviation melanomas and had positive sentinel node biopsies (60%). Among the thirteen patients for whom there was not information on primary tumor thickness, two of these patients had positive sentinel lymph node biopsies and one patient had positive lymph nodes found during elective node dissection. A fourth patient underwent therapeutic lymph node dissection for clinically positive nodes. The overall instance of positive lymph nodes was 17.8% in young melanoma patients and 9.6% in the thickness matched adult control patients. Ten years survival was similar between the young melanoma patients and adult melanoma patients with 89.4% and 79.3% respectively. There was no significant difference in survival between young and adult melanoma patients after stratification by stage of disease in the multivariate analysis. In univariate analysis predictors of survival in the young melanoma patients were the median thickness, 2.9 in prepubescent versus 2.3 millimeters for patients who had negative lymph nodes. The presence of ulceration, Clark s Level IV, and the AJCC tumor classification stages T3 and T4 were all associated with poor prognosis. No patient below twenty-years of age that had a thickness of one millimeter or less died from the disease.

4 In this particular study, we chose to evaluate patients up to twenty years of age with the thirteen year cut off, prepubescent children showed no difference in disease free survival. As indicated, however, the factors of influenced melanoma specific survival in patients at twenty years of age and below were thickness, again to Clark level, the presence of positive lymph nodes and AJCC stages 3 or 4. One of the interesting findings in this study were that a highest percentage of young melanoma patients had positive family histories for melanoma and atypical nevi. The fact that the lesions occur early in life and that there was no finding of lentigo maligna melanoma, may be evidential with regard to the role of sun in childhood melanoma. Possibly, there is much less importance in the role of the sun in these groups. The problem of the aggressiveness of melanoma in the young, may relate to the fact that children s melanomas are thicker when they present then those of their adult counterparts. Also, physicians have possibly a lower threshold for clinically suspecting melanoma in young children. Certainly, in our personal experience, some lesions were delayed as long as two years before the patients either presented with ulceration or metastasis. These patients had been told by their pediatricians that there lesions were benign. This reports of melanoma in the young document fiveyear survival rates of 70-80% which is much lower than the 91.3% five year survival rate in this particular study. Of course, it must be emphasized that we analyze melanoma specific mortality in comparing survival rates between adult and children. A high frequency of the rates of sentinel node, in this particular study, should be commented upon. In our study, 50% are patients who had sentinel nodes biopsied positive in patients below twentyone years of age. In another large series, sited below, Toro et al noted only 25% positivity. The mean thickness in our patients that underwent sentinel node biopsy was 2.5 mm compared to 1.7 millimeters in the Toro study. Finally, there s an interest that the borderline lesions in our series had positive sentinel nodes in 60% of cases very similar to the study of Lohmannet al that is sited below. Many more studies including prospective studies need to be performed in order to further understand the behavior of these unusual lesions.

5 A review of the histologic features of malignant melanomas that resulted in death in children and adolescents will be presented. Selective references: 1. Trozak DJ, Rowland WD, Hu F. Metastatic malignant melanoma in prepubertal children. Pediatrics. 1975;55: Elder DE, Xu X. The approach to the patient with a difficult melanocytic lesion. Pathology. 2004; 36: Ceballos PI, Ruiz-Maldonado R, Mihm MC Jr. Melanoma in children. N Engl J Med. 1995;332: Reintgen DS, Vollmer R, Seigler HF. Juvenile malignant melanoma. Surg Gynecol Obstet. 1989; 168: Rao BN, Hayes FA, Pratt CB, et al. Malignant melanoma in children: its management and prognosis. J Pediatr Surg. 1990; 25: Toro J, Ranieri JM, Havlik RJ, Coleman JJ 3 rd, Wagner JD. Sentinel lymph node biopsy in children and adolescents with malignant melanoma. J Pediatr Surg. 2003; 38: Lohmann CM, Coit DG, Brady MS, Berwick M, Busam KJ. Sentinel lymph node biopsy in patients with diagnostically controversial Spitzoid melanocytic tumors. Am J Surg Pathol. 2002; 26: Scalzo DA, Hida CA, Toth G, Sober AJ, Mihm MC Jr. Childhood melanoma: a clinicopathological study of 22 cases. Melanoma Res. 1997; 7: Spatz A, Ruiter D, Hardmeier T, et al. Melnaoma in childhood: an EORTC-MCG multicenter study on the clinicopathological aspects. Int J Cancer. 1996; 68: