Juxtaoral Organ of Chievitz, an Obscure Anatomical Structure Masquerading as Perineural Invasion of Mucoepidermoid Carcinoma

Abstract

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.

Juxtaoral organ: an anatomical finding to be considered

“…In our case the JOO appeared bilaterally, which agrees with what was described by Ito et al [10] and Sancheti et al [24], while the location and relations observed are consistent with what has been established in the literature [2,16,25], ruling out the possibility that it is an accessory parotid gland, as this presents a more superficial location and is relative to the parotid duct [21]. In our finding we observed a close proximity of the JOO to the roots of lower third molar, which could imply its exposure and/or damage during oral surgeries, although due to the little or no functionality that it seems to have, we consider that this damage might not be relevant to an individual's physiology.…”

“…Histologically the JOO is made up of nests or cords of epithelial cells that resemble a non-keratinised flat stratified epithelium with peripheral basal cells in a palisade arrangement, as well as some cylindrical cells with clear cytoplasm forming cords or glandu-lar-like tubular structures that can at times present an associated secretion product negative for mucin [24]. The epithelial cells of the JOO do not present mitotic figures and they may occasionally be associated with dystrophic calcifications.…”

“…The lines represent the way in which the dimensions of the JOO were measured anteroposteriorly and transversally. mitotic figures, no foci of inflammation or necrosis in the stroma [24], and with preservation of the epithelial basal membrane [20]. There is only one report of a benign tumour derived from cells of the JOO in the temporal region [21], and there is no evidence of a malignant lesion originating there.…”

“…In any case, it does not seem to play a relevant role in the functions of the stomatognathic apparatus, which reinforces the idea of its vestigial nature. Nevertheless, knowing its location and histological characteristics is valuable because several authors have reported that its presence in surgical specimens subjected to histopathological analysis with a diagnosis of squamous cell carcinoma may be confused with a perineural invasion of tumour cells [10,24], which can have considerable influence on a patient's prognosis.…”

Neuroepithelial Structures of the Oral Soft Tissues Including the Juxtaoral Organ of Chievitz: A Literature Review and Audit of Diagnosed Cases

“…Melanin pigment was present in 1 case and calcification in 2 cases. The finding of the JOOC medial to the angle of the mandible and with these histological features is further supported by four single case reports [4][5][6][7] (Table 2). Areas of degeneration resulted in microcystic changes The structure was described as a hamartoma [10] Base of tongue Biopsy of described slight abnormality 39 M Nests of bland squamoid cells close to small nerves [9] There is a single case report of the JOOC on the medial of the mandibular angle showing structures resembling Pacinian corpuscles.…”