Pilomatrixoma Presenting as a Rapidly Expanding Mass of the Infant Nasion.

Pilomatrixomas are benign neoplasms originating from the cells of hair follicles. They typically present as a slowly enlarging, solitary mass on hair-bearing areas of the head and neck. While a common childhood lesion, pilomatrixomas are unusual in infancy. Our objective is to present an atypical pilomatrixoma located on the midline nasion of an 11-month-old as such a lesion and its management has not been previously described. Despite preoperative diagnostic imaging, including computed tomography and magnetic resonance imaging, the diagnosis was not made until examination by pathology after complete surgical excision. We also completed a thorough review of the literature pertaining to pilomatrixomas, which is presented in a concise fashion. Our patient's clinical presentation did not correlate with traditional descriptions in the literature, skewing preoperative diagnosis. However, surgical management was ultimately appropriate and effective. To date, the patient has not demonstrated evidence of recurrence. We believe that this is the first such reported presentation of a pilomatrixoma. Given its incidence, we encourage readers to consider this diagnosis when evaluating similar pediatric skin lesions of the head and neck. Complete surgical excision is the definitive treatment.