Monostostic fibrous dysplasia with nonspecific cystic degeneration: A case report and review of literature

Abstract

Fibrous dysplasia (FD) has been regarded as a developmental skeletal disorder characterized by replacement of normal bone with benign cellular fibrous connective tissue. It has now become evident that FD is a genetic disease caused by somatic activating mutation of the Gsα subunit of G protein-coupled receptor. Here we report a case of bilateral monostotic FD in a middle-aged female showing a classic histological picture, but radiologically presenting as a mixed radiolucent radiopaque lesion showing nonspecific cystic degeneration.

Keywords: Fibrous dysplasia; monostotic; nonspecific cystic degeneration.

Figure 1

Clinical photograph showing swelling on the right side of the mandible

Figure 2

Clinical photograph showing diffuse swelling on the left lower border of the mandible

Figure 3

Orthopantomogram showing well-defined multilocular radiolucency with specks of radiopacity in the right and left posterior mandible

Figure 4

Occlusal radiograph showing expansion and thinning of the buccal and lingual cortex on both sides of the mandible with ground glass appearance

Figure 5

Computed tomography scan showing well-defined lytic lesions involving right and left posterior mandibular region with thinning and expansion of buccal and lingual cortical plates

Figure 6

Cystic cavities in relation to the swelling on the left side of the mandible which were empty on surgical exploration

Figure 7

Macroscopic picture of the resected lesional hard tissue of the left side, creamish white in color, with irregular surface. Cystic cavities with hemorrhagic areas are seen on the inner aspect

Figure 8

Photomicrograph of the lesion on the right side showing numerous delicate trabeculae arranged in different forms lacking osteoblastic rimming. Intervening spaces showed fibrous proliferation (H&E stain,; (a) ×40, (b) ×100). (c) Polarizing microscopic photomicrograph showing normal bone on the periphery, cascading into immature bone (H&E stain, ×40)

Figure 9

Photomicrograph of the lesion on the left side showing calcified spherules composed of immature bone. Intervening spaces showing fibrocellular proliferation (H&E stain (a) ×40, (b) ×100). (c) Polarizing microscopic photomicrograph showing calcified spherules composed of immature bone (H&E stain, ×40)