From Libre Pathology
|Diagnosis in short|
Fibrous dysplasia. H&E stain.
|LM||woven bone with odd irregular shapes (often described as "chinese characters"), fibrous tissue around bone, no osteoblastic rimming|
|LM DDx||desmoplastic fibroma, low-grade fibrosarcoma, low-grade central osteosarcoma|
Fibrous dysplasia, also osteitis fibrosa, is a rare disorder of bone that has a distinctive microscopic appearance.
- Monostotic - one bone involved, ~80% of cases.
- Polyostotic - several bones involved, ~20% of cases.
- May be associated with McCune-Albright syndrome.
- Woven bone with odd irregular shapes - key feature.
- Described as "chinese characters".
- Fibrous tissue around bone.
- No osteoblastic rimming.
- Desmoplastic fibroma - has lamellar bone.
- Low grade fibrosarcoma.
- Low-grade central osteosarcoma.
- Gnathic ossifying fibroma (Cemento-ossifying fibroma) - Prominent calcified spherules, no associated GNAS mutation
- Gnathic ossifying fibroma recurs and needs to be completely enucleated
- Fibrous dysplasia may be self limited and can be followed with observation or if symptomatic bisphosphonate therapy is an option.
- S0, distinguishing between these two entities is important
- Fibrous dysplasia of bone - high mag. (pathologypics.com).
- Fibrous dysplasia of bone - low mag. (pathologypics.com).
- Modern Pathology- fibrous dysplasia (left) vs ossifying fibroma (right)
- Postzygotic (somatic) activating mutations of the GNAS1 gene 10, which encodes the α-subunit of the stimulatory G-protein Gs
- Both mono and polyostatic cases.
- Causative molecular lesion of McCune-Albright and Mazzabraud syndrome
- URL: http://www.pathologypics.com/pictview.aspx?id=104. Accessed on: 14 April 2011.
- URL: http://www.pathcases.com/bone_tumors_and_tumor.htm. Accessed on: 31 May 2011.
- Inwards, CY (2001). "Low-grade central osteosarcoma versus fibrous dysplasia". Pathology Case Reviews 6 (1): 22-27. http://journals.lww.com/pathologycasereviews/Fulltext/2001/01000/Low_Grade_Central_Osteosarcoma_Versus_Fibrous.5.aspx.
- Patel, MM.; Wilkey, JF.; Abdelsayed, R.; D'Silva, NJ.; Malchoff, C.; Mallya, SM. (May 2010). "Analysis of GNAS mutations in cemento-ossifying fibromas and cemento-osseous dysplasias of the jaws.". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 109 (5): 739-43. doi:10.1016/j.tripleo.2009.12.016. PMID 20346714.
- Weinstein, LS.; Shenker, A.; Gejman, PV.; Merino, MJ.; Friedman, E.; Spiegel, AM. (Dec 1991). "Activating mutations of the stimulatory G protein in the McCune-Albright syndrome.". N Engl J Med 325 (24): 1688-95. doi:10.1056/NEJM199112123252403. PMID 1944469.