Osteoblastoma and Osteoid Osteoma of the Mandible: Review of the Literature and Report of Two Cases

Abstract

Osteoblastoma and osteoid osteoma are rare benign neoplasms of the jaws. We reviewed current literature surrounding the ongoing debate over similarities and differences of osteoblastoma and osteoid osteoma and present two cases. Both cases are well-demarcated mixed radiodensity mandibular lesions with histological features of osteoblastoma. They exhibit, however, distinctly unique and contrasting clinical and imaging characteristics suggesting that the first case is osteoblastoma and the second is osteoid osteoma. The first case of a 37-year-old male presents with a large, expansile lesion at posterior mandible, surrounded by a thick sclerotic band. Unusual features include significant buccal/lingual expansion, extensive new bone apposition, and soft tissue edema in the masseter muscle. This is in contrast to the second case of a much smaller lesion in a 17-year-old male with history of recent third molar extraction in the left posterior mandible. In this case, CT imaging revealed a circular, nonexpansile lesion with a sclerotic border surrounded by a radiolucent rim. Both patients underwent surgical excision of the lesion with extraction of the adjacent tooth. We discuss herein the distinct clinical and imaging features.

Figure 1

Case #1 3D CT reconstruction (a) and bone window CT sagittal view (b) showing the mixed density lesion associated with impacted #17 measuring 1.6 × 2.1 × 2 cm. The border of the lesion is well circumscribed with a broad sclerotic rim surrounding a lucent halo. Axial views ((c-f) from superior to inferior) and coronal views ((g-j) from posterior to anterior) showing buccal and lingual expansion, thinning, and areas of perforation at buccal and lingual cortices (arrowheads). Extensive sclerotic reactive bone is seen surrounding the lesion. New bone formation can be seen at buccal, lingual cortical, and inferior to the lesion (arrows). The lucent rim of the lesion extends into the left mandibular canal, with potential involvement of the inferior alveolar nerve (g–j).

Figure 2

Case #1, soft tissue window CT images. Axial views (a–b) and coronal views (c–d) showing edema within the adjacent left masseter muscle (arrows).

Figure 3

(a) Panoramic radiograph of case #2 prior to third molar extraction showing partially developed and bony impacted #1, 16, 17, and 32. No signs of pathology noted around the impacted #17. (b) Clinical photo post extraction with noted scar tissue at #17 extraction site but otherwise no abnormalities or swelling.

Figure 4

(a) Case #2 panoramic radiograph. (b and c) 3D CT reconstruction, viewed from the lingual aspect. (d) CBCT sagittal view. (e–f) Bone window CT axial views. (g–h) Bone window CT coronal views. (i) Soft tissue window CT coronal view. Panoramic radiograph was taken 8 months postsurgical extraction of the impacted tooth #17. An exophytic mixed density lesion, measuring 1.2 × 1.0 × 1.1 cm, emanated from the distal root of tooth #18. The border of the lesion is well-demarcated with a sclerotic rim surrounded by a lucent rim. Small area of bony sclerosis is noted at buccal and superior of the lesion (arrows) (g and h). There was no evidence of root resorption at associated root of #18. Unlike case 1, there is no evidence of expansion, new bone formation, or adjacent soft tissue edema (i).

Figure 5

(a) Case #1 panoramic radiograph one month post excisional biopsy showing the lesion and #17 completely removed with bony sclerosis still visible. (b) Case #1 surgical specimen. (c) Case #1 intraoperative clinical photo. (d) Case #2 surgical specimen showing the lesion in association with the distal root of #18.

Figure 6

Histological features of case #1 (a and b). (a) Decalcified bone with evident reversal lines with prominent osteoblastic activity. Note the vascular connective tissue stroma with dilated blood vessels and hemorrhage (H&E stain, ×40). (b) A higher magnification of panel (a) showing the bone with prominent and large osteoblasts with abundant cytoplasm and epithelioid morphology (H&E stain, ×100). (c and d) Histological features of case #2. (c) Decalcified bone with reversal lines with prominent osteoblastic activity. Note the vascular connective tissue stroma with dilated blood vessels and small foci of hemorrhage (H&E stain, ×40). (d) A higher magnification of panel (c) showing the bone with prominent and large osteoblasts with abundant cytoplasm and vascular connective tissue stroma with dilated blood vessels and scattered erythrocytes (H&E stain, ×100).