Introduction:
Mammary-type extramammary myofibroblastoma (MTEM) is a rare mesenchymal
neoplasm that is histologically and immunohistochemically identical to
mammary myofibroblastoma.1 These extramammary
neoplasms are composed of spindle cells, usually arise in the
subcutaneous tissues, and traditionally express desmin, Smooth Muscle
Actin (SMA), and CD34; they are closely related to spindle cell lipomas
and cellular angiofibromas.2 Presentation outside of
the embryological mammary crest is exceedingly rare, where involvement
of extramammary sites classically includes the inguinal and groin area,
vulva, perineum, and scrotum.1 There is a paucity of
cases reporting head and neck MTEM following radiotherapy, and even more
so concerning the nasal sinuses.3-7
We report a case of radiation induced MTEM requiring maxillectomy and
ethmoidectomy. This lesion was most likely secondary to distant
periorbital radiotherapy, which the patient sustained during treatment
for retinoblastoma during childhood.