Noonan syndrome-like disorder: Case report and review of the literature.

Of patients with a Noonan syndrome phenotype, only about 1% are found to be related to pathological variants in CBL, also known as Noonan syndrome-like disorder (NSLD). We present a case of a 4-year-old boy diagnosed with NSLD, presenting with multiple melanocytic nevi and superficial neurofibromas. A literature review identified common cutaneous findings of NSLD, for example, café-au-lait macules (22%), juvenile xanthogranuloma (16%), and thin hair (10%). As there are no documented cases of neurofibromas associated with NSLD, and only a single report of multiple melanocytic nevi, inclusion of these features in the phenotype may be warranted and mitigate the necessity for future biopsies in other children.

Novel CD63-PRKCB fusion in a case of pigmented epithelioid melanocytoma.

Pigmented epithelioid melanocytoma (PEM) is an intermediate-grade melanocytic tumor with considerable histologic overlap with other melanocytic neoplasms such as epithelioid blue nevus (EBN), which is associated with the neoplastic syndrome Carney complex (CC). Next-generation sequencing is a valuable tool for identifying the primary drivers of melanocytic neoplasms and differentiating them from one another. While germline variants in the protein kinase cAMP-dependent regulatory type 1 alpha (PRKAR1A) gene have been associated with EBN and CC, fusions in protein kinase C-alpha (PRKCA) have been shown as sporadic drivers of PEM. Herein, we report the diagnosis and workup of a case of pigmented epithelioid melanocytoma with a novel protein kinase C-beta (PRKCB) fusion.

Eruptive nevi in a patient with constitutional mismatch repair deficiency (CMMRD).

Biallelic mutations in the DNA mismatch repair genes MLH1, MSH2, MSH6, or PMS2 result in one of the most aggressive genetic cancer conditions, constitutional mismatch repair syndrome (CMMRD). We present a case of a 10-year-old boy with biallelic MSH6 mutation and systemic lupus erythematosus with eruptive melanocytic nevi after receiving chemotherapy for mediastinal T-cell lymphoblastic lymphoma.

Eruptive agminated nevi in a successfully treated Langerhans cell histiocytosis patient.

A 7-year-old girl with a history of Langerhans cell histiocytosis (LCH), in remission, presented with the sudden appearance of multiple, agminated nevi. Skin biopsy revealed a benign junctional nevus, without recurrence of LCH. Subsequent immunohistochemical testing of both the skin and iliac wing biopsies demonstrated a BRAF V600E mutation. MAPK pathway mutations have been implicated in both LCH and nevogenesis.

Review article: Emerging issues in pediatric skin of color, Part 2.

Dermatology for pediatric skin of color is the application of dermatology to the genetically diverse and distinctive segment of the pediatric population that includes children of non-White racial and ethnic groups with increased pigmentation including individuals of Asian, Hispanic/LatinX, African, Native American, Pacific Island descent, indigenous people among others with overlap in particular individuals, and mixtures thereof. The discipline of pediatric skin of color can be challenging with difficulty in diagnosis of common conditions due to underlying pigmentation, variations in common hair styling practices, and differences in demographics of cutaneous disease. Whereas some conditions are more common in children of color, other conditions have nuances in clinical appearance and therapeutics with regard to skin color. This article, the second of the series, focuses on inflammatory skin disease nuances, melanocytic disorders, and hypopigmented mycosis fungoides.

Neurocutaneous melanocytosis-associated malignant melanoma presenting with peritoneal seeding.

Neurocutaneous melanocytosis (NCM) is characterized by melanocyte deposition in the leptomeninges and brain parenchyma, primarily occurring in children with large or giant congenital melanocytic nevi (LCMN) or multiple congenital melanocytic nevi. Patients with NCM may develop hydrocephalus and increased intracranial pressure, which can be managed with ventriculoperitoneal (VP) shunting. We present the case of a 16-month-old girl who developed peritoneal carcinomatosis and malignant ascites following VP shunting for hydrocephalus secondary to NCM to increase awareness of this rare, but serious, complication of cerebrospinal fluid diversion.

Reflectance confocal microscopy in pediatric dermatology: A state-of-the-art review.

Reflectance confocal microscopy is an innovative imaging modality, which noninvasively provides an optical image to aid in the diagnosis of skin lesions. While performing a skin biopsy for histopathologic analysis is the gold standard to definitively diagnose skin disease, this may prove to be more difficult in the pediatric population. This will occasionally necessitate sedation or general anesthesia as an approach, which carries a number of different risks. Reflectance confocal microscopy is an exciting new avenue in the support of diagnosing skin pathology, with the goal of improving pediatric patient tolerance and experience when examining epidermal and superficial dermal skin lesions. This review discusses the utility of reflectance confocal microscopy for pediatric dermatology patients pertaining to melanocytic and non-melanocytic skin neoplasms and inflammatory and infectious skin diseases in children.

Increased melanocytic nevi and lentigines in two patients with harlequin ichthyosis.

An increased number of melanocytic nevi and lentigines have been reported in patients with two types of autosomal recessive congenital ichthyosis (ARCI): lamellar ichthyosis and nonbullous congenital ichthyosiform erythroderma. These melanocytic lesions may have clinical and dermoscopic features of atypia, necessitating close surveillance. Here, we report two interesting cases of pediatric patients with harlequin ichthyosis (HI) who developed increased melanocytic nevi and lentigines. These cases are unique in that the patients presented at a younger age and one patient had a darker skin phototype than previously described in the literature.

Pine tar callus: A mimicker of a melanocytic lesion.

We report a case of acral pigmented lesions due to pine tar, a common compound used on baseball bats to improve grip, deposition. The patient presented with an acute concern for a new melanocytic lesion, and dermoscopy revealed large brown globules, not typical of melanocytic neoplasms. We propose that the coupling of dermoscopy and a thorough clinical history of exogenous exposures in similar clinical presentations can provide reassurance in evaluating atypical appearing pigmented lesions.

Should we biopsy melanonychia striata in Asian children? A retrospective observational study.

BACKGROUND AND OBJECTIVES: Melanonychia striata is common in children of darker-skinned Asian races, while subungual melanoma is extremely rare and it is difficult to make a diagnosis clinically. However, performing nail unit biopsies in children is particularly challenging and can result in permanent nail dystrophy. The aim of this study was to review the clinical and histologic characteristics of melanonychia striata in pediatric patients of Asian descent to aid in the clinical decision regarding nail biopsy. METHODS: Sixty-two pediatric patients presenting with melanonychia striata involving single or multiple nails at two tertiary pediatric dermatology clinics in Singapore between 2005 and 2015 were reviewed. Clinical and histopathological data were analyzed, including age at onset, age at presentation, location, color, width, presence of Hutchinson's sign, pseudo-Hutchinson's sign, nail dystrophy, length of follow-up, and clinical evolution. Histopathological assessment was performed by three senior dermatopathologists independently for cases that underwent a nail biopsy. RESULTS: No cases of subungual melanoma were detected in our series. Solitary melanonychia of the thumbnail with a single uniform color was the most common presentation. Pseudo-Hutchinson's sign was commonly observed. Consensus in histological diagnosis emerged amongst all three dermatopathologists in only half of the cases biopsied. CONCLUSION: The occurrence of melanoma in Asian children presenting with melanonychia is extremely rare. We recommend clinical follow-up and anticipatory guidance for these patients and nail unit biopsy only in the presence of high-risk clinical features.

A cut above the rest: Trimming as a painless depilatory.

Shaving and other modes of epilation can cause undue anxiety, pain, or skin irritation in children. Here, we present hair trimming as a safe, painless, and cost-effective alternative for patients with unwanted hair which may be performed indefinitely or until the child is old enough to direct management. In select cases, removing unwanted hair using this technique may facilitate dermatologic surveillance.

Agminated segmental plaque-type blue nevus associated with hypertrichosis and soft tissue hypertrophy: Report of a case and review of the literature.

Blue nevi are common skin neoplasms that typically present as asymptomatic solitary papules, although they may rarely occur in an agminated configuration. We describe a case of agminated blue nevus in a segmental facial distribution associated with soft tissue hypertrophy and hypertrichosis in a 16-year-old boy and present a review of the literature. Although they are generally considered to be benign, concurrent soft tissue changes occurring within an agminated blue nevus should be investigated thoroughly to exclude alternate diagnoses.

Aggressive melanoma in an infant with congenital melanocytic nevus syndrome and multiple, NRAS and BRAF mutation-negative nodules.

We report the case of a newborn boy with multinodular NRAS and BRAF mutation-negative congenital melanocytic nevi and cerebral lesions compatible with congenital intraparenchymal melanosis. Histopathology from skin lesions showed atypical nodular melanocytic proliferation with marked melanocytic atypia and a large number of mitoses and apoptosis, indicating aggressive proliferation. The child developed several new subcutaneous tumors and multiple internal lesions, which were confirmed to be metastases, and died at 5 months of age. This case may represent an infantile melanoma developing from a giant congenital melanocytic nevus or a congenital melanoma.

Molluscum contagiosum arising in a melanocytic congenital nevus.

Molluscum contagiosum within a congenital melanocytic nevus has rarely been reported. We report a 6-year-old child with molluscum contagiosum infection arising within an intermediate melanocytic congenital nevus of the thigh, associated with itching and occasional bleeding. Dermoscopy lead to the correct diagnosis, but histologic confirmation with shave biopsy was performed to reassure the parents and allow mechanical removal of the lesions using curettage.

Angiomatoid and desmoplastic Spitz nevus presenting as a keloidal nodule.

Angiomatoid and desmoplastic Spitz nevi are rare histologic variants of Spitz nevi that present most frequently on the extremities of children and young adults. Although Spitz nevi are clinically heterogeneous, one presenting as a keloidal nodule has not been previously published. We present a case of an angiomatoid and desmoplastic Spitz nevus clinically akin to a keloid on an African-American teenager and describe its unique histopathologic features.

Germline BRCA1-associated protein 1 mutation presenting as BAP1 inactivated melanocytic nevi in a child of a father with fatal paraganglioma.

BRCA1-associated protein 1(BAP1) inactivated melanocytic nevi are pink to tan and dome-shaped in clinical appearance, resembling dermal nevi, but with distinct histologic features of two melanocytic subpopulations: larger atypical melanocytes and nests of smaller, blander nevoid melanocytes. Pedigrees with BAP1 mutations are at greater risk of various malignancies. We report the case of a 16-year-old boy with multiple benign-appearing nevi, all demonstrating loss of BAP1 on immunohistochemistry. History revealed that his father had died of paraganglioma, which is also associated with BAP1 mutations.