Calcified subgaleal hematoma with secondary cranial deformity in a patient with Kasabach-Merritt phenomenon.

We present here the case of a 25-month-old boy who, in conjunction with his preexisting Kasabach-Merritt phenomenon (KMP), developed a massive calcified subgaleal hematoma (SGH) with secondary cranial deformity. Kasabach-Merritt phenomenon is a rare condition that involves a secondary consumptive coagulopathy in the setting of congenital hemangiomatous lesions. The vascular lesions of KMP are often large, singular, and cutaneous, but may also be diffuse, and involve internal structures. Subgaleal hematomas are a rare condition, most frequently observed in neonates as a complication of instrument-assisted delivery. There have been few cases reported beyond the perinatal period, but those that are present within the literature have typically resulted from some instance of minor trauma to the scalp. Most cases resolve spontaneously and without complication. However, our patient's SGH developed into a large, organized, and calcified lesion, likely with some contribution from his hematologic deficit. In addition, this subgaleal lesion resulted in a cranial deformity, ultimately requiring surgical evacuation and reconstruction. We believe the case presented here represents the first report of an SGH in the setting of KMP.