Case report of a challenging medium-sized congenital melanocytic nevus (CMN): Highlighting a role for reflectance confocal microscopy (RCM) for evaluating changing CMN in children.

A 3.5-month-old boy presented with a changing medium-sized congenital melanocytic nevus on his leg. Due to atypical features on dermoscopy and reflectance confocal microscopy (RCM), an excision of the area of concern was performed. Histopathology showed many of the pathological features usually associated with a diagnosis of melanoma in situ in older patients, but due to the young age of the patient, absence of mitoses, and the degree of atypia, a diagnosis of a dysplastic compound nevus arising in a congenital compound (predominantly dermal) nevus was favored. In our case, RCM corresponded to histopathology helped target the area of concern and map the clinical and subclinical components to facilitate an optimal biopsy.

CM-AVM syndrome - A prospective observational study of unrelated paediatric cases.

OBJECTIVE: The main objective of this study is to describe the clinical spectrum of CM-AVM syndrome as well as radiological and genetic findings. METHODS: This is a single-centre prospective observational study performed at Sydney Children's Hospital. Patients under the age of 18 years that presented to our paediatric dermatology clinic or vascular birthmark clinic between January 2015 and September 2020 with one or more geometric shaped pink/ red/ brown macule with a peripheral pallor characteristic of a high-flow vascular stain were included. Children subsequently diagnosed with other diagnosis or family members with CM-AVM syndrome were excluded. RESULTS: Sixty children were included, with two subsequently excluded. A third of patients (n = 22, 38%) presented with a single characteristic HFVS, whereas the remaining two thirds (n = 36; 62%) had multiple HFVS. In children with multiple HFVS, one notably larger HFVS was detected in the majority of children (n = 32, 88%). In 33 patients, a brain and spine MRI was performed, which detected a spine AVM in one symptomatic patient with sensorimotor deficits. No cerebral AVM or AVF was picked up in the cohort. A RASA 1 result was available for evaluation in 24, of which 16 (67%) were positive. An EPHB4 result was available in eight, two (25%) of which were positive. CONCLUSIONS: One large HFVS often accompanied by multiple small HFVS can be seen in most patients. Despite of the lack of genetic confirmation of diagnosis in single lesions, this phenotype might be of interest and warrants further investigation.