Adenoid Cystic Carcinoma of Pterygopalatine Fossa: Report of a Rare Case.

Adenoid cystic carcinoma (ACC) is an uncommon malignant neoplasm that predominantly arises from major and minor salivary glands, accounting for about 1% of head and neck malignancies. ACCs originating from the pterygopalatine fossa (PPF) are extremely rare. In this case report, we present a 77-year-old male patient who experienced a two-year hemi-facial numbness and mild trismus, with intact nasal mucosa. He underwent Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) which revealed opacification of the left PPF with extension to the left infratemporal fossa and osteolytic areas of the sphenoid bone. Histopathology, following blind biopsies, revealed ACC of the PPF, which was subsequently treated with combined therapy (radiotherapy and chemotherapy). Due to their slow and progressive growth, as well as their tendency for perineural invasion, ACCs should always be considered in the differential diagnosis of painless swelling or nerve dysfunction. To our knowledge, this case is the fifth described in the English literature.