Answer : B . Stafne defect ( SD )
Stafne defect ( SD ) is a normal anatomic variation . It represents a concavity in the cortical bone in the lingual mandible where a portion of a salivary gland rests , most frequently the submandibular gland . Clinically , the lesion is asymptomatic . Usually , it is thought to represent a developmental disorder that is believed to be congenital in nature , but it develops with time and presents in middle-aged to older adults . SD is not rare , and are present in 0.08 to 0.48 % of panoramic radiographs , with a striking 80-90 % male predilection . 1 Usually they are unilateral , but can present bilaterally .
Radiographically , they typically present as an asymptomatic , round to oval-shaped well-defined radiolucencies at the body or angle of the posterior mandible , often inferior to the IANC or occasionally overlapping the IANC . 2 Clinically , they present as a focal concavity or notch on the lingual surface of the mandible , but palpation of the area is difficult due to the overlap of other anatomic structures . Most commonly , 57 percent of cases present in the first molar and bicuspid area . 2 Occasionally , they have been noted to appear in other locations of major salivary glands , including the anterior mandible in association with the sublingual gland , or the ascending ramus in association with the deep tail of the parotid . 1 However , there have been cases that contained a cavity with muscle , fibrous / connective tissue , blood or lymphatic vessels , lymphoid tissue , or adipose tissue . 2 If present more anteriorly , the lesion may appear superimposed over the apices of teeth , mimicking periapical lesions . 1 , 2
SD may be diagnosed on radiographic presentation , in conjunction with the clinical findings , namely , the lack of symptoms . Advanced imaging may be performed if the features on plain film imaging are not conclusive . Conventional or cone beam computed tomography imaging , magnetic resonance imaging ( MRI ), or even sialography can be used for diagnosis . MRI is quickly becoming the method of choice to determine the type of tissue present within the cavity , because it uses comparisons of tissues based on their soft tissue densities . 3 Biopsy is indicated if there is clinical suspicion of a pathologic lesion . Surgical exploration usually reveals normal salivary tissue in the defect . 2 , 3 Since the defect represents an anatomic variation of normal , treatment is not indicated . In this case , given the presentation of asymptomatic , well-defined , bilateral radiolucencies inferior to the IANC , near the angle of the mandible in a middle-aged male , SD was considered high on the list of the differential diagnoses . No biopsy was performed in this case due to the lack of suspicion of any pathologic processes . Periodic radiographic observation is recommended .
Discussion
A . Traumatic neuroma is considered to be a reactive process rather than a neoplastic process . It forms as an exaggerated response to injury from a severed or damaged nerve bundle ’ s attempt to regenerate . 4 The proximal portion of the nerve attempts to re-establish innervation to the distal portion of the nerve . In the case of trauma , scar tissue may inhibit this reinnervation , and this causes a tumor-like mass to form as the nerve continues to regenerate to establish connection . 1 TNs can occur at any site of trauma , but they are more common in the area of the mental foramen , lower lip , and tongue . 4 , 5 They commonly occur after surgery or after extraction of the teeth with roots close to the inferior alveolar canal . Radiographically , these may be seen intraosseously as well , presenting as a well-delineated , radiolucency with diffuse borders that are contiguous with the inferior alveolar nerve canal or mental foramen ( Figure 2 ). The lesions are most commonly diagnosed in middle-aged adults , but they can occur at any age and there is a slight female predilection . 4 They can present as a smooth nodule with up to one third of patients presenting with pain that can ranging from mild tenderness to severe burning , but paresthesia , anesthesia , or dysesthesia may occur . The pain is caused by compression of the nerve by the lesion itself . 4 Histologically , TNs appear as haphazard proliferations of mature nerve bundles in a fibrous stroma . It is usually a proliferation of the perineurium , epineurium , and endoneurium of the nerve as well as Schwann cells , and regenerating axons . 6 Inflammation may or may not be present . Treatment involves surgical excision of the lesion , including a small portion of the proximal nerve . The majority of lesions do not recur ; however , there are reports of persistent pain and recurrence of the lesion after excision .
30 JANUARY / FEBRUARY 2017 | PENNSYLVANIA DENTAL JOURNAL