Pain remains a common and frequently debilitating symptom, particularly during adulthood of Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS). For many FD/MAS patients, the amount of pain perceived is not commensurate with the level of detectable musculoskeletal pathology. Using a combination of clinical and biological assessments, this investigation aims to understand what drives pain in FD/MAS.

In Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS), healthy bone tissue and marrow is replaced with pre-osteoblastic, fibrous tissue, yielding skeletal deformities and an increased propensity towards fracture, musculoskeletal weakness and bone pain. Despite the frequent use of pharmacological and non-pharmacological analgesic strategies, pain in FD remains common and frequently debilitating, particularly during adulthood. Moreover, for many patients there is a discordance between perceived pain levels and detectable musculoskeletal pathology. To elucidate the mechanism underlying pain in FD/MAS patients, investigators at the National Institute of Dental and Craniofacial Research (NIDCR), National Center for Complementary and Integrative Heath (NCCIH) and Boston Children's Hospital (BCH) aim to probe three inter-related domains that are projected to underlie pain experience(s) in FD/MAS patients. These include (i.) the presence of maladaptive central nervous system processes that amplify afferent pain or somatosensory signals, and also facilitate persistent pain; (ii.) aberrant interplay between neurological and musculoskeletal systems; (iii.) a mental health status shaped by the overall burden of living with FD and (iv.) the influence of childhood, FD-related complications on adulthood pain phenotypes. To investigate these four domains hypothesized to underlie FD pain as well as inform on the disconnect between pain and FD disease burden, the investigators will employ methods that complement routine clinical evaluation and diagnostic tests (i.e., 18F-NaF PET/CT or 18F-FDG PET/CT) such as neuroimaging, musculoskeletal MRI and such as neuroimaging, musculoskeletal MRI and assessment of inflammatory and pain mediator expression in blood samples.

Inclusion Criteria (FD/MAS patients):

• Male and Female subjects
• 10-45 years of age
• English Speaking ability sufficient to comprehend consent (with parental assistance if minor)
• Diagnosis of Fibrous Dysplasia

Exclusion Criteria for patients:

• Younger than 10 or older than 45 years old
• Weight > 285 lbs (weight limit of the MRI table and < 36lbs)
• Surgery leaving implanted material
• Contraindications to MRI scanning and PET scanning (including presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia, previous significant research related exposure to ionizing radiation)

Exclusion Criteria for healthy controls:

Same as for the patients, with the addition of the following:

• Use of recreational or illicit drugs History of chronic pain

A two-way material transfer agreement has been executed between collaborating parties (Boston Children's Hospital and NIH)

Individual data will start to become available 12/2019 and last for 1.5 years.

A two-way material transfer agreement

Individual performing data analyses will be blinded to whether dataset corresponds to FD/MAS patient or matched healthy control