Adenoid cystic carcinoma arising in the inferior orbit without evidence of lacrimal gland involvement

A 60-year-old woman sought treatment for right orbital fullness and intermittent headache. CT revealed an inferior orbital mass along the inferior rectus muscle. Incisional biopsy revealed an adenoid cystic carcinoma. Orbital exenteration followed by concurrent radiotherapy and chemotherapy was performed. The lacrimal gland was uninvolved by tumor microscopically. Although rare, adenoid cystic carcinoma must be considered in the differential diagnosis of an orbital tumor, because the unusual location of an orbital adenoid cystic carcinoma may make its early detection difficult.