Juxtaoral Organ of Chievitz, an Obscure Anatomical Structure Masquerading as Perineural Invasion of Mucoepidermoid Carcinoma: Case Report and Review of Literature.

The juxtaoral organ was first described by Chievitz in 1885. This is typically located deep to the medial pterygoid muscle (unilaterally or bilaterally) in the pterygomandibular space. Juxtaoral organ of Chievitz (JOOC) is usually incidentally detected in biopsies or resection specimen of other tumors but exceptionally, it can present as mass lesions. Awareness of this normal anatomic structure is important, because the epithelial islands in this area could be misinterpreted as an invasive carcinoma, mucoepidermoid carcinoma, an odontogenic tumor such as ameloblastoma or adenomatoid odontogenic tumor, or a perineural invasion by carcinoma. When a portion of the juxtaoral organ of Chievitz is accidentally exposed by frozen biopsy, there is an even higher risk of mistaking these cells for an invasive cancer or a perineural invasion of carcinoma. We report this to create awareness about this obscure structure and to draw attention to its differential diagnosis.