COM July 2016

Unilocular radiolucency right ramus

Contributed by Drs. Srinivasa Chandra and Mathew Callan
Oral & Maxillofacial Surgery, Harborview Medical Center & Bremerton, WA

Case Summary and Diagnostic Information

July2016-1
This is a 44-year-old Caucasian female who presented to the clinic for black spot on the jaw x-ray.

History of present Illness

This is a 44-year-old Caucasian female who presented to the clinic ‘to figure out what the big black spot on the jaw x-ray was’ (Figure 1). The patient reported no pain, no swelling or drainage, and no difficulty in mouth opening or sensory perception. She also reported no history of any injury to this region; this condition was noted on a routine radiographic examination at the general dentist’ office. She had third molars removed years ago.

July2016-1

Figure 1  This is a panoramic radiograph taken at first presentation demonstrating a well-demarcated to corticated unilocular radiolucency in the right mandibular ramus anterior to the mandibular canal.

Medical History

Her past medical history included surgical removal of appendix and wisdom teeth. She reported ‘whitecoat’ hypertension. She denied tobacco smoking or drug use and reported consuming alcohol on social occasions. She had no known allergies.

Clinical and Radiographic Findings

Clinically, the patient had no facial asymmetry. Mouth opening was adequate to about 40 mm. Panoramic x-ray revealed a unilocular well-circumscribed radiolucent lesion of the right ramus measuring 26 mm x 19 mm. An MRI scan with and without contrast revealed a right mandibular ramus expansile lesion, T2 hyperintense, T1 hypointense, homogeneously enhancing mass measuring 24 mm anterior posteriorly, 16 mm superior inferior and 11 mm in transverse. The mass was well-circumscribed with no evidence of cortical perforation, periosteal reaction, and invasion into the adjacent musculature or marrow edema. There was mildly restricted diffusion associated with the mass. No other osseous lesions were identified.

July2016-1

Figure 1  This is a panoramic radiograph taken at first presentation demonstrating a well-demarcated to corticated unilocular radiolucency in the right mandibular ramus anterior to the mandibular canal.

July2016-2
Figure 2 This image represents an axial section of an MRI scan with a T2 hyperintense homogenous mass of the right mandibular ramus.

Treatment

Under general anesthesia, a transoral right mandibular ramus axis osteotomy was performed. A tannish-pink soft tissue mass was encountered in continuity with the right inferior alveolar nerve. The mass was gently excised. Considering the significance of the mass in continuity with the nerve dissection was performed to excise the nerve associated mass and a primary neuropathy was performed with magnification with an 8-0 nylon suture. Hemostasis was achieved and the nerve was protected. Primary closure of the surgical access was achieved. Six-month follow-up revealed a complete mandibular nerve sensory recovery with good mouth opening.

July2016-2
Figure 3 This image represents a panoramic radiograph taken six months after surgery. Note the right mandibular ramus defect with circumferential bone filling as demonstrated by the increased radio density. Compare this image to Figure 1 to note the difference.

Incisional and excisional biopsy

The histology revealed multiple pieces of a cellular soft tissue mass made up of spindle-shaped cells; some arranged in short bundles crisscrossing and focally forming Verocay bodies (Figures 4 & 5). In other areas, the spindle shaped cells were less organized and haphazardly arranged. The immunohistochemistry stain with antibody to S100 is uniformly positive (Figure 6).

July2016-4
Figure 4 Low power (X100) H & E stained section revealing a cellular soft tissue mass made up of spindle-shaped cells crisscrossing each other and forming Verocay bodies.

July2016-5
Figure 5 Higher power (X200) H & E stained section revealing a closer look of the Verocay bodies

July2016-6
Figure 6 Higher power (X100) Immunohistochemistry stain with antibody to S100 protein revealing a cellular soft tissue mass made up of uniformly positive spindle-shaped cells.

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