Mazabraud syndrome

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Mazabraud syndrome

ORPHA:57782Malformation syndrome

Also called Myxoma with fibrous dysplasia

What it is

Mazabraud syndrome is a rare primary bone dysplasia characterized by the association of fibrous dysplasia with intramuscular myxomas. Fibrous dysplasia (usually polyostotic, sometimes monostotic) occurs during the growth period and can be asymptomatic or can present with pain, skeletal deformities or fractures while intramuscular myxoma, associated with polyostotic fibrous dysplasia is usually multifocal, typically occuring in the vicinity of skeletal lesions, and presents in adulthood as a painless soft-tissue mass (most commonly in the thigh). Although it is a benign condition, local recurrences of myxomas after incomplete excision and malignant transformation of a fibrous dysplastic lesion into osteogenic sarcoma have been reported.

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Adult
Inheritance
Not applicable
Classified as
Malformation syndrome

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Gene

GNASCandidate gene tested

ICD-10 codes

M85.0filed under a broader ICD-10 category — shared with 2 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

MEDDRA 10081724MONDO 0018933UMLS C3697137

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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