A Frequently Missed Diagnosis of a Firm, Blue-Tinged Mass

An otherwise healthy 5-year-old girl presents to the outpatient pediatric clinic for evaluation of a left temporal mass that has been slowly growing for the past month. The mass is nonpruritic, mildly tender to the touch, and not associated with drainage. There is no recent history of local trauma, including insect bites or scrapes. There is no family history of similar lesions or other skin disorders. Physical examination reveals a solitary 0.4 × 0.6-cm papule that is firm, mildly tender to the touch, and skin-colored to a faint blue–maroon color on the left side of her temple (Fig 1). The remainder of her physical examination findings are normal. She is referred to pediatric dermatology for evaluation and consultation. A clinical diagnosis is made, with dermatology consultation further supporting the diagnosis through dermatoscopy. Treatment options were presented, and the family elected to observe the lesion for several months before...