Vulvar Mastocytosis in Children and Adolescents: A Case Series

Pediatric cutaneous mastocytosis is a rare condition characterized by clonal mast cell accumulation in the skin, most commonly presenting on the trunk and extremities. Vulvar involvement is exceedingly rare, particularly as an isolated lesion.

We retrospectively reviewed five pediatric cases of vulvar mastocytosis: one case from a children's hospital and four cases enrolled in an NIH protocol for mastocytosis (NCT00044122).

Five girls (aged 16 months to 15 years), initially presented to the NIH or tertiary children's hospital with lesions on the vulva characterized as flesh colored or hyperpigmented nodules or papules, which first emerged as early as day 1 of life and up to 5 years. In three patients, the vulvar lesions were their initial presenting symptom of mastocytosis. On exam, four patients had a positive Darier's sign, a pathognomonic localized wheal response due to mast cell degranulation. All cases were confirmed histologically with typical dermal mast cell infiltrates. Tryptase levels, also used to evaluate suspected systemic involvement, were initially elevated in two patients, one of which was eventually diagnosed with systemic mastocytosis.

This is the largest reported case series of vulvar mastocytosis in pediatric patients to date. These cases highlight the variability in presentation and the importance of considering a biopsy for histopathologic confirmation. Early evaluation and recognition can lead to appropriate work up, prevent misdiagnosis, guide management including evaluation of systemic disease, and provide appropriate counseling, education, and reassurance to patients and their families.