Lesiones melanocíticas subungueales en la edad pediátrica

Adult and Pediatric Nail Unit Melanoma: Epidemiology, Diagnosis, and Treatment

“…Despite the rising rate of NUM diagnoses in adults, NUM diagnoses in pediatric patients are extremely rare [ 22 ]. Only 21 cases of NUM in children have been reported to date, with only 4 cases diagnosed as invasive and no instances of metastasis or death; there is controversy surrounding these cases, their pathology, and whether they are true cases of melanoma [ 75 ] ( Figure 10 , Figure 11 , Figure 12 and Figure 13 ). All figures we include of pediatric cases were reported and described as NUM, although there may be disagreement about these diagnoses.…”

“…Diagnosis is challenging since no clear criteria have been established to differentiate between melanocytic activation, nail unit nevi, and NUM in children. While certain features (i.e., band width, pigment involving the nail folds) may guide the decision to perform a biopsy of LM to rule out NUM in adults, benign pediatric melanonychias may manifest similarly to adult NUM [ 75 , 78 , 79 ]. Pediatric nail unit nevi most often involve the thumbnail and may appear with a dark brown to black band, the band width being >3 mm, involve the entire nail plate with pigment extending to the proximal nail fold, and have irregular bands on dermoscopy [ 78 ].…”

“…The most frequent cause of LM in childhood is a nail matrix nevus, in contrast to adult LM, which is most commonly caused by melanocytic activation [ 75 , 80 , 81 , 82 ]. In a retrospective study of 40 children less than 16 years who had biopsies, lentigo or nevus accounted for 77.5% of cases, with no patients diagnosed with NUM [ 83 ].…”

“…Diagnosis and management of NUM in children remain controversial; differences in opinion on the exact diagnosis, lack of complete evidence in publications, and absence of aggressive clinical course in all cases contribute to ongoing discussions about the accuracy of diagnosing NUM in children [ 75 , 80 ]. One of the unknowns is at what age a person should be considered a child vs. an adult for purposes of assessing LM.…”

“…Furthermore, histopathological features of NUM used as indicators in adults, such as prominent lentiginous growth, prominence of single melanocytes, or cytologic atypia, may be associated with benign diagnoses in children [ 76 ]. Other benign melanocytic cutaneous lesions in children, such as Spitz nevi, often have atypical architectural characteristics or cytologic atypia, but follow no aggressive clinical course [ 75 ]. This has led more researchers and pathologists to support the notion that atypical lentiginous melanocytic hyperplasia in children does not carry the same malignant potential as in adults [ 75 ].…”