The elusive BAP1 mutation in pediatric melanocytic tumors.

Cutaneous BAP1-inactivated melanocytomas (BIM) are melanocytic proliferations defined histopathologically by an epithelioid, predominantly dermal melanocytic proliferation with loss of BAP1, and have been largely characterized in adult patients but less well-described in pediatric cohorts. BIM share overlapping histological features with those seen in Spitz nevi; however, unlike Spitz nevi, the majority of BIM carry both BAP1 and BRAFV600E mutations. This study investigated the potential overlap of BIMs with pediatric Spitz nevi by performing immunohistochemical staining of BAP1 and BRAFV600E on pediatric melanocytic tumors with banal Spitz and dermal features. None of the stained tumors in our study exhibited the concurrent BAP1 loss and BRAFV600E positivity that are characteristic of adult BIM, suggesting that this is a low-frequency mutation among banal tumors in the pediatric population.

Melanoma-like features in pediatric longitudinal melanonychia: A systematic review and meta-analysis.

BACKGROUND: Pediatric longitudinal melanonychia (LM) can exhibit atypical features that mimic red-flag signs for subungual melanoma in adults and lead to diagnostic uncertainty. Nail biopsy may be unnecessary if clinical inspection and dermoscopy suggest a benign nature. METHODS: We searched PubMed and Embase from inception to February 2023 for studies of any design reporting either the number or proportion of clinical and dermoscopic features in at least five children (≤18 years) with LM. Non-English articles, reviews, and abstracts were excluded. We performed a systematic review and meta-analysis to collate all existing data. RESULTS: A total of 1218 articles were screened and 24 studies with 1391 pediatric patients were included. Nevus was the most common diagnosis (86.3%). The most prevalent sites were fingernails (76.2%) and first digits (45.4%). Pooled proportions of common features were: dark-color bands (69.8%), multi-colored bands (47.6%), broad bandwidth (41.1%), pseudo-Hutchinson sign (41.0%), irregular patterns (38.1%), Hutchinson sign (23.7%), dots and globules (22.5%), nail dystrophy (18.2%), and triangular sign (10.9%). Outcomes included progression (widening or darkening, 29.9%), stability (23.3%), and spontaneous regression (narrowing or fading, 19.9%). Only eight cases of subungual melanoma in situ were reported, and no invasive melanomas were identified. CONCLUSION: Although atypical characteristics are common in pediatric LM, the probability of malignant transformation is exceedingly low. Appropriate evaluation and management of pediatric LM includes careful clinical and dermoscopic inspection with attention to benign features followed by long-term interval follow-up.

Updates in the Management of Congenital Melanocytic Nevi.

Congenital melanocytic nevi (CMN) carry an increased risk of melanoma and may be disfiguring, and consensus regarding treatment recommendations is lacking. While clinical monitoring is the standard of care, many caregivers are interested in its removal to prevent psychosocial burden or to decrease risk. Although melanoma can occur regardless of CMN removal, there are a variety of treatments that may offer improved cosmesis or local symptom control, including surgical excision, laser therapy, and other superficially destructive techniques. Regardless of the selected management, these patients are monitored for ongoing melanoma risk. An extensive discussion with families regarding the risks and benefits of observation versus active intervention is essential. To facilitate these discussions, we herein summarize current CMN management strategies and considerations.

Non-vascular intracranial lesions in three children with PHACE association.

PHACE (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac anomalies, eye anomalies) association has many recognized clinical features. A link between PHACE and non-vascular intracranial lesions has not been well-described. We report three pediatric patients with PHACE and non-vascular intracranial lesions.

Features, management, and outcomes of pediatric scalp melanomas.

Pediatric melanoma of the scalp has the highest mortality of any anatomic location. We describe five pediatric patients with a diagnosis of scalp melanoma receiving care at Massachusetts General Hospital and/or Boston Children's Hospital from 2018 through 2022. Melanoma presented in diverse contexts: cellular blue nevus-associated, compound nevus-associated, spitzoid, nodular, and superficial spreading subtypes. This study describes a range of melanoma presentations and emphasizes the need for additional compilation of data on pediatric scalp melanomas to promote their recognition and improve patient care.

Spectrum of lymphatic anomalies in patients with RASA1-related CM-AVM.

BACKGROUND: Capillary malformation-arteriovenous malformation (CM-AVM) is characterized by multifocal fast-flow capillary malformations, sometimes with arteriovenous malformations/fistulas, skeletal/soft tissue overgrowth, telangiectasias, or Bier spots. Lymphatic abnormalities are infrequently reported. We describe seven patients with CM-AVM and lymphatic anomalies. METHODS: Following IRB approval, we identified patients with CM-AVM and lymphatic anomalies seen at the Vascular Anomalies Center at Boston Children's Hospital from 2003 to 2023. We retrospectively reviewed records for clinical, genetic, laboratory, and imaging findings. RESULTS: We found seven patients with CM-AVM and lymphatic abnormalities. Five patients were diagnosed prenatally: four with pleural effusions (including one suspected chylothorax) and one with ascites. Pleural effusions resolved after neonatal drainage in three patients and fetal thoracentesis in the fourth; however, fluid rapidly reaccumulated in this fetus causing hydrops. Ascites resolved after neonatal paracentesis, recurred at 2 months, and spontaneously resolved at 5 years; magnetic resonance lymphangiography for recurrence at age 19 years suggested a central conducting lymphatic anomaly (CCLA), and at age 20 years a right spermatic cord/scrotal lymphatic malformation (LM) was detected. Chylous pericardial effusion presented in a sixth patient at 2 months and disappeared after pericardiocentesis. A seventh patient was diagnosed with a left lower extremity LM at 16 months. Six patients underwent genetic testing, and all had RASA1 mutation. RASA1 variant was novel in three patients (c.1495delinsCTACC, c.434_451delinsA, c.2648del), previously reported in two (c.2603+1G>A, c.475_476del), and unavailable in another. Median follow-up age was 5.8 years (4 months-20 years). CONCLUSION: CM-AVM may be associated with lymphatic anomalies, including pericardial/pleural effusions, ascites, CCLA, and LM.

Metopic ridge presenting to pediatric dermatology and vascular anomalies clinics.

Metopic ridge (MeR) is a midline osseous forehead prominence resulting from physiologic closure of the underlying metopic suture. This mass-like ridge can be mistaken for serious conditions such as a craniosynostosis or vascular anomaly, prompting concern and workup. We reviewed patients presenting for a forehead mass to Vascular Anomalies and Dermatology clinics and diagnosed with MeR to increase familiarity with this finding and to encourage MeR in the differential diagnosis of pediatric midline forehead masses.