A 5-day-old male neonate was referred to our vascular anomalies center with a large cystic submandibular mass. History and physical examination and ultrasonographic results indicated the diagnosis to be macrocystic lymphatic malformation. Consequently, the child was treated with sclerotherapy and subtotal excision. The histopathological examination result showed that the lesion was infantile myofibroma. This diagnostic error was attributed to atypical features of infantile myofibroma in this child: unusually large cysts, rapid enlargement, and coagulopathy. This report expands the clinical spectrum of infantile myofibromatosis and suggests its consideration in the differential diagnosis of neonatal cystic cervicofacial lesions.