116 Test 98.2 ORAL MEDICINE Developmental Mandibular Salivary Gland Defect The Importance of Clinical Evaluation developmental mandibular salivary gland defect (also known as static A bone cyst, static bone defect, Stafne bone cavity, latent bone cyst, latent bone defect, idiopathic bone cavity, developmen- tal submandibular gland defect of the mandible, aberrant salivary gland defect in the mandible, and lingual mandibular bone Sako Ohanesian, concavity) is a deep, well-defined depression DDS in the lingual surface of the posterior body of the mandible. More precisely, the most common location is within the submandibu- lar gland fossa and often close to the inferi- or border of the mandible. In developmental bone defects investigated surgically, an aberrant lobe of the submandibular gland extends into the bony depression. First recognized by Dr. Edward Stafne in 1942, numerous cases of developmental mandibular salivary gland defect have since been reported, and the lesion should not be considered rare.1 In a study of 4963 pan- Most authorities now agree that this entity is a congenital defect, although it has rarely been observed in children and its precise anatomic nature is still uncertain. oramic images of adult patients, 18 cases of Figure 1. CT slices/panoramic views showing a well-defined radiolucent lesion in the right mandible. salivary gland depression were found by Karmiol and Walsh2, an incidence of nearly 0.4%. Most authorities now agree that this The margins of the radiolucent defect are around an extension of salivary tissue. This entity is a congenital defect, although it has well-defined by a dense radiopaque line. theory is supported by findings of radiolu- rarely been observed in children and its pre- This cortical margin is usually thicker on cencies in association with each of the 3 sali- cise anatomic nature is still uncertain. Also the superior aspect. This appearance is the vary glands. Most surgical series have noted unexplained is the fact that far more cases result of the x-rays passing tangentially salivary tissue within the bony defect, but have been reported in men than in women.3 through the relatively thick walls of the muscle, lymphatic tissue, and blood vessel The lesion, usually asymptomatic and depression. It is occasionally bilateral. The have also been reported. discovered during routine radiographic ex- radiolucent defect may represent either The lesion may be regarded properly as amination, appears as an ovoid radiolucen- actual enclavement of salivary gland tissue a developmental defect rather than a patho- cy, generally situated between the mandibu- within the mandible during embryonic logic lesion. Histologically, normal salivary lar canal and the inferior border of the development or, more frequently, an inden- tissue is found, and no treatment is required mandible, just anterior to the angle. Rare tation on the mandible with a portion of the except routine radiographic follow-up. It can examples are located in the apical region of submaxillary gland lying within the defect. and should be differentiated from the trau- the mandibular premolars or cuspids, and Salivary gland defects are presumed to form matic bone cyst (also referred to as hemor- are related to the sublingual gland fossa. by the remodeling of the mandibular cortex continued on page 118 DENTISTRY TODAY • FEBRUARY 2008 118 ORAL MEDICINE Developmental Mandibular... continued from page 116 Xxxx...Table. Comparison of Various Lesions That Can Be Confused With Static Bone Defect. 7,12,13 Etiology Clinical Presentation Radiographic Findings Diagnosis Treatment Prognosis Traumatic Unknown in most cases; may Peaks in second decade; usual- Clearly defined radiolucency; Radiographic appearance; clini- Surgical exploration; observa- Excellent; small risk of recur- bone cyst be due to traumatic injury pro- ly in body of mandible; pain- margins may be uneven but cal finding of an empty bony tion for resolution. rence. ducing intramedullary hemor- less in most cases; swelling clear; may extend between space (pseudocyst); collagen rhage and subsequent clot noted in one fourth tooth roots creating and fibrin line the dead space; resorption; alternative theory of cases. a scalloped pattern. lamellar bone may be noted suggests degeneration of pri- along the bony margin. mary intrabony pathology. Mandibular salivary Developmental depression of No symptoms; discovered Round to ovoid radiolucency Radiographic appearance. Recognition only. Excellent. gland defect (Stafne the lingual side of the incidentally. below inferior alveolar canal, bone cavity) mandible; the aberrant lobe of above inferior border and the submandibular salivary below third molar area; well- gland and/or adipose tissue defined by a dense hypercorti- fills the body of mandible cated margin; size range of one defect; depression created pro- to 3 cm; rarely noted in premo- duces characteristic radi- lar and canine areas. ographic findings. Periapical A radicular cyst that most likely Often, periapical cysts do not Located approximately in the A cyst that becomes large may Treatment of a tooth with a Excellent; recurrence is cyst results when rests of epithelial produce symptoms unless sec- apex of a nonvital tooth; occa- cause swelling; the swelling radicular cyst may include unlikely if removed completely. cells in the periodontal liga- ondary infection occurs. sionally, appear on the mesial may feel bony and hard if the extraction, endodontic therapy, ment are stimulated by inflam- or distal surface of a tooth cortex is intact, crepitant as the and apical surgery; treatment matory products from a nonvi- root, at the opening of an bone thins, and rubbery if of a large cyst usually involves tal tooth. accessory canal, or infrequent- bone destruction has occurred; surgical removal or marsupial- ly in a deep periodontal pocket; outline of cyst is usually ization. most (60%) found in the curved or circular unless maxilla. influenced by surrounding structures such as cortical boundaries. Dentigerous A developmental odontogenic Most commonly involves fre- Well-defined radiolucency Cysts without secondary Cyst enucleation and extraction Excellent; possible complica- cyst cyst arising subsequent to sep- quently impacted teeth: enclosing crown of unerupted inflammation are thin, cuboidal, of associated tooth; marsupial- tions include: pathologic frac- aration between dental follicle mandibular third molars, fol- tooth; corticated/opaque mar- nonkeratinized epithelial lining ization prior to excision may be ture with large lesions and and the crown of an associated lowed by maxillary canines; gins unless infected; may pro- 2 cell layers thick with flat considered if very large. neoplastic transformation of unerupted tooth; proliferation usually noted during second duce root resorption of adja- epithelial-connective tissue epithelial lining. of reduced enamel epithelium and third decades; asympto- cent erupted teeth; usually interface; loosely arranged col- lining the follicle, with fluid matic and discovered on rou- unilocular; less commonly lagen bundles; cysts with sec- accumulation between epitheli- tine radiographic examination; multilocular. ondary inflammation have um and impacted tooth crown; painless jaw/alveolar expansion hyperplastic, nonkeratinized degeneration of the stellate may occur; cortex is thinned squamous epithelial lining with reticulum component of enam- and rarely perforated. epithelial ridge development; el organ occurs during odonto- variable chronic inflammatory genesis. cell infiltrate within condensed collagen stroma. Odontogenic A benign, aggressive develop- 5% to 15% of odontogenic Can occur in any area of maxil- Radiographic features. Excision with curettage of bony Recurrence rate varies from keratocyst mental odontogenic cyst; may cysts; usually occurs sporadi- la or mandible; rarely may confines. 10% to 30% (greatest in be associated with mutation of cally as an isolated finding; arise in gingival soft tissue patients with a syndrome). PTCH tumor suppressor gene. about 5% are associated with only, mandible is preferred site nevoid basal cell carcinoma; in 65% to 78% of cases; often 5% of patients have multiple seen in a dentigerous relation- odontogenic keratocysts ship; discrete radiolucency, (OKCs) and no syndrome. usually in relation to teeth; may be unilocular to multilocular. Nonossifying Unknown in most cases; Majority of all NOFs are On plain film radiographs, Histologically, the lesions con- Treatment varies depending on Generally excellent. fibroma lesions occur as a result of asymptomatic and are discov- NOFs appear as eccentric, tain whorled bundles of con- the size and severity of the developmental aberrations at ered incidentally on radi- multi or uniloculated, ovoid nective tissue cells admixed NOF; surgery is often not the epiphyseal plate; not neo- ographs; symptomatic lesions lesions in the metaphysis of with foamy histocytes, hemo- required to treat NOF due to a plasms, but developmental may present with mild pain bone with sclerotic margins; siderin, hemorrhage, collagen, high rate of spontaneous defects; tend to occur after the and swelling of short duration; lesions may extend into the multinucleated giant cells, and regression and a lack of symp- age of 2, a muscle pull and may have bone tenderness medullary cavity; long axis of bone trabeculae. toms; symptomatic lesions periosteal injury may be a con- with palpation. the NOF is most commonly should first be treated conserv- tributing factor. seen parallel to the long