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Braz J Otorhinolaryngol. 2016;xxx(xx):xxx---xxx

www.bjorl.org

Brazilian Journal of

OTORHINOLARYNGOLOGY

CASE REPORT

Stafne bone cavity containing ectopic parotid gland�

Cavidade óssea de Stafne contendo glândula parótida ectópica

Mesut Kaya ∗, Kadriye Serife Ugur, Elif Dagli, Hanifi Kurtaran, Mehmet Gunduz

Department of Otolaryngology Head & Neck Surgery, Turgut Ozal University, Faculty of Medicine, Ankara, Turkey

Received 3 February 2016; accepted 8 February 2016

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Introduction

In 1942, Stafne1 described 35 asymptomatic cases of a corti-cal depression of the lingual side of mandible with unilateralradiolucent cavities located in the posterior region of themandible, between the third molar and mandibular angle,below the inferior mandibular canal and above the mandibu-lar base. He reported the cases as ‘‘bone cavities situatednear the angle of the mandible’’. These lesions are definedas pseudocysts without an epithelial lining. Although themajority of these cysts are seen in the jaw angle below themandibular nerve, they are also diagnosed in other locationssuch as the anterior mandible. As its controversial pathogen-esis explanations, this lesion has been called of many namesincluding static bone cavity or defect, latent or idiopathicbone cavity, ectopic submandibular or sublingual gland inthe mandible, lingual cortical mandibular defect or depres-sion, developmental bone defect of the mandible and Stafnecyst, defect or cavity.

Considering most of the cases, Stafne cavity is diagnosedincidentally in routine radiologic examinations in asymp-tomatic patients. In panoramic radiograms it appears to bea dense circumscribed radiolucency in mandibular angle,

� Please cite this article as: Kaya M, Ugur KS, DagliE, Kurtaran H, Gunduz M. Stafne bone cavity contain-

ing ectopic parotid gland. Braz J Otorhinolaryngol. 2016.http://dx.doi.org/10.1016/j.bjorl.2016.02.004

∗ Corresponding author.E-mail: mesutkaya78@yahoo.com (M. Kaya).

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http://dx.doi.org/10.1016/j.bjorl.2016.02.0041808-8694/© 2016 Associacão Brasileira de Otorrinolaringologia e Cirurgiaaccess article under the CC BY license (http://creativecommons.org/lic

elow mandibular canal, mostly in one focus. Stafne cystsre considered stable structural changes of the mandiblend do not require surgical intervention. But in literature,here are reports of patients operated for this entity, withescriptions of cavities containing submandibular gland tis-ue, muscles, fibrous connective tissue, blood vessels, fatr lymphoid tissue.2 In this particular paper we present atafne bone cavity containing ectopic parotid gland.

ase report

60-year-old male patient with complaint of pain in rightide of floor of mouth, was referred to our otolaryngologylinic of a tertiary academic center, with a MRI study showing

solid mass of the right submandibular region diverging fromurrounding structures, such as submandibular gland anduscles with regular borders. The lobulated mass showediffuse contrast retention and intermediate density in T1Aections, hyperintensity in T2 images and did not suppressedn fat suppressed series. Also this mass was filling the spaceituated anteriorly to the right mandibular angle, formed as

well-bordered cortical depression with an intact inferiorandibular line (Fig. 1).The patient was having pain for 3 months and antibi-

tics and anti-inflammatory agents had been used, with noain relief. A panoramic radiography demonstrated an oval

haped and well-bordered cystic lesion between the secondolar and the mandibular angle, slightly above the inferiorandibular line. The third molar had been extracted many

ears ago, and the cyst was not involving the second molar

Cérvico-Facial. Published by Elsevier Editora Ltda. This is an openenses/by/4.0/).

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Figure 1 The magnetic resonance images of the lobulated mass of right submandibular region (black arrows) in T1A sections (A),and in T2 fat suppressed sections (B and C).

Figure 2 Oval shaped, well-bordered cystic lesion (whiteaa

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Figure 3 Intraoperative photo of lobulated mass (whitearrow) presented through the window opened lateral mandibu-lar wall of Stafne cyst.

rrow) between second molar and the mandibular angle, slightlybove the inferior mandibular line in panoramic radiograph.

oots. Surrounding borders of the cyst were more denseFig. 2). Head and neck examination revealed no pathologicnding and no pain at palpation of the neck.

An informed consent was obtained and surgical treatmentook place. Intraoral incision was performed on the buccalucosa near the gingivobuccal line. Periosteum of mandibleas lifted trough the inferior mandibular line and a win-ow was opened from the buccal side of mandible using

burr. The mass could be observed just behind the thinortical outer plate and the cavity did not have any epithe-ial lining. It was non-capsulated, solid, fragile and easilyetachable from the submandibular gland and muscles, buttrictly attached inferiorly to lingual nerve (Fig. 3). The massas removed without complication.

The mass was glandular like shape macroscopicallyFig. 4). Histopathologic findings showed the presence oflandular tissue and ectopic parotid gland (Fig. 5). Acinarells contained zymogen granules and ductal system wasntact. Thereafter we again looked at MRI images to verifyf both parotid glands were present in their usual locations.

iscussion

ccessory parotid gland is a glandular tissue located onhe masseter muscle, lying closely or craniolateral to the Figure 4 Macroscopic image of ectopic parotid tissue.

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Figure 5 In hematoxylin-eosin staining, the mass was consistecells contained zymogen granules and ductal system was intact

Stensen’s duct, but separated from anterior border of theparotid gland. Accessory parotid gland has a specific ductalsystem which drains into the Stensen’s duct.3 Presence ofparotid gland tissue outside the natural place or accessorylocation is called ectopia and can be seen with or withoutthe absence of the parotid gland at its normal location. Inthe embryo, between sixth and seventh week, major sali-vary glands start to develop as ectodermal invaginations inthe floor of the branchial part of the primitive mouth forparotid gland, and a formation of endodermal invaginationsfor submandibular and sublingual glands. These cells migrateinto the underlying mesenchyme starting their opening ofthe future excretory duct. During embryogenesis, all sali-vary glands show close interactions with adjacent lymphatictissue which explain why ectopic salivary gland tissue mostcommonly located in the cervical lymph nodes.4 In the liter-ature very rare locations of ectopic salivary glands have beenreported, including pineal gland, thyroglossal duct, thyroidgland, parathyroid gland, pharyngeal tonsil, lingual tonsil,rectum, stomach and vulva. Although salivary gland hetero-topia in various organs is observed, well organized salivaryglandular tissue, or a well structured ectopic parotid glandare very rare conditions.5 Developmental abnormalities ofthe branchial apparatus end up with malformations likesinuses, fistulas or cysts. Youngs and Schofield6 suggestedthat ectopia of salivary gland is a result of an anusual per-sistence and differentiation of the endodermal remnants ofthe pre-cervical His sinus.

Ectopic salivary glands mostly arise from the anterior tri-angle along the medial edge of sternocleidomastoid muscleand the most common location is the base of the neck.7

Usually ectopic salivary glands present as sinuses openingexternally and secreting a clear liquid like saliva especiallyduring eating. Bilateral presentation of ectopic salivarygland is rare.

Barbuscia et al.8 described ectopic parotid gland of themiddle neck, structured as normal parotid parenchyma withmulti-lobular appearance. Histological examination whichis most similar to our case, revealed, acinar glands with

serous secretions containing abundant zymogen granules inits compounds, completely preserved.

Our case of ectopic parotid gland was located in Stafne’scavity. When Stafne1 introduced this entity, he advocated

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pure serous glandular tissue in 100× magnification (A). Acinar0× magnification (B).

he developmental theory, saying that it could occur dueo a deficiency in ossification in the area filled by Meckel’sartilage. However, it seems unlikely because no presenta-ion under 11 age has been reported, and peak of incidences usually around the fifth and sixth decades. A widelyccepted theory is that the mandibular defect occurs due toressure atrophy caused by the submandibular gland, sinceostoperative findings have confirmed the presence of sub-andibular salivary gland in the cavity.9 Quesada-Gómez

t al., noted a compensatory hypertrophy and fibrosisaused by lymphocytic infiltration and reduced secretingnd increasing in size with age. Minowa et al. showedbnormal vasculature in cavity both radiologic imaging andistopathologically rather than salivary glands, and sug-ested that vascular lesion could be another explanation fortiology of Stafne cyst. It was proposed that the recanal-zation of thrombosis, and occlusion of branches of theacial artery could become tortuous because of arterioscle-osis and hypertension which increase with age, consistentith the peak of incidence. Although the submandibularland can weaken arterial pulses, the mandible is sub-ected to pressure from the arterial pulses. The pressuren the mandible is thought to be the cause of the boneavity.

Content of the pseudocyst is usually inflamed salivaryland which is the most common finding in operated or imag-ng studies of Stafne cavity. Muscles, fibrous tissue, fat,ymphoid tissue, vascular structures or devoid of contentre reported in a minority of cases.9 Considering theobility of the mouth floor and neck, unintentional dis-lacement of adjacent tissues during surgical manipulationr intermittent gland repositioning may occur. Our case sup-orts the glandular pressure theory with ectopic parotidland.

The diagnosis of the classic appearing of Stafne cyst,n the posterior lingual aspect of the mandible, is easilyade with a panoramic radiograph. Stafne cyst’s differ-

ntial diagnosis includes odontogenic or non-odontogenicystic lesions, fibrous dysplasia, non-ossifying fibroma,

rown tumor of hyperparathyroidism, osteoporotic bonearrow defect, ameloblastoma, giant cell tumor, benign

alivary gland tumors, hemangioma, myxoma, multipleyeloma, eosinophilic granuloma and metastatic disease.9

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lso considering the mass filling the cavity, benign oralignant lymphadenopathy, lymphomas, cystic hygroma,

emangiomas, neurogenic tumors, benign or malign glandu-ar tumors should be in mind.10 With the use of Computerizedomography (CT), CT-sialography and Magnetic Resonancemaging (MRI), differential diagnosis can be made.

All authors made an agreement that Stafne bone cystoes not require surgical treatment and radiologic follow-uphould be recommended for the management of the boneepression, because it can be considered an anatomicalondition rather than a pathological entity. Biopsy or sur-ical exploration should be thought only if the diagnosis isncertain or unusual exceptional disease is suspected. In theresent case we preferred surgical exploration based on MRIndings presenting with anatomic deficiency. Histopatho-

ogic outcome revealed a developmental pathology, ectopicarotid gland which according to our knowledge is the firstase in the English literature.

onclusion

tafne bone cyst is a rare, benign anatomic entity mostlyeen as posterior lingual depression of mandible and inur case it is associated with aberrant but well organizedarotid glandular tissue originating dislocation from the

haryngeal pouches. According to our case and previouseported cases, advanced imaging studies must be obtainedn order to eliminate the possibility of potentially dangerousiseases.

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onflicts of interest

he authors declare no conflicts of interest.

eferences

1. Stafne EC. Bone cavities situated near the angle of themandible. J Am Dent Assoc. 1942;29:1969---72.

2. Minowa K, Inoue N, Sawamura T, Matsuda A, Totsuka Y, Naka-mura M. Evaluation of static bone cavities with CT and MRI.Dentomaxillofac Radiol. 2003;32:2---7.

3. Frommer J. The human accessory parotid gland: its incidence,nature, and significance. Oral Surg. 1977;43:671---6.

4. Warnock GR, Jensen JL, Kratochvil FJ. Developmental disease,surgical pathology of the salivary glands. Philedelphia: WB Saun-ders; 1991. p. 10---25.

5. Carney JA. Salivary heterotopia, cysts and the parathyroidgland: branchial pouch derivatives and remnants. Am J SurgPathol. 2000;24:837---45.

6. Youngs LA, Schofiled HH. Heterotopic salivary gland tissue in thelower neck. Arch Patol. 1967;83:550---6.

7. Jernstrom P, Prietto CA. Accessory parotid gland tissue at thebase of neck. Arch Pathol. 1962;73:473---80.

8. Barbuscia MA, Caizzone A, Vecchio DA, Mirone S, PutortìA, Cingari EA, et al. Ectopic parotid: case report. G Chir.2011;32:429---33.

9. Quesada-Gómez C, Valmaseda-Castellón E, Berini-Aytés L, Gay-

Escoda C. Stafne bone cavity: a retrospective study of 11 cases.Med Oral Patol Oral Cir Bucal. 2006;11:277---80.

0. Simpson W. A stafne’s mandibular defect containing a pleomor-phic adenoma: report of case. J Oral Surg. 1965;23:553---6.