Abstract
We report a case of infantile myofibromatosis (solitary type) in a 2-day-old male. A dark reddish tumor of 25×20mm was found on a nuchal lesion after birth. We suspected a fibrous tumor on magnetic resonance imaging (MRI) findings. On histological examination, spindled cells and ovoid cells were arranged in short bundles and fascicles. On immunohistochemical examination, α-smooth muscle actin and vimentin stains were positive and Azan-Mallory stains were dyed blue. Based on these findings, we diagnosed this tumor as infantile myofibromatosis (solitary type).
Infantile myofibromatosis is a rare tumor of infancy, and cases often have a good prognosis with spontaneous regression of the lesions. The patient was therefore followed without antitumor therapy, and the tumor regressed gradually.
