RESUMEN
BACKGROUND AND SIGNIFICANCE: McCune Albright Syndrome (MAS) is a rare disorder characterized by the clinical triad of precocious puberty, polyostotic fibrous dysplasia of the bones and café-au-lait spots. Prevalence is estimated at 1/100,000-1/1,000,000. We report a case of polyostotic fibrous dysplasia in a patient with McCune Albright Syndrome who had symptomatic relief of hip pains and non-recurrence of stress fractures in a dysplastic right hip bone following treatment with loading intravenous pamidronate followed by an oral alendronate for almost a year, as an off-label indication. While intravenous bisphosphonates have been well-recognized in the treatment of fibrous dysplasia, only case reports are available to support its utility.CASE REPORT: We report an 18 year old female with leg length discrepancy following repeated episodes of hip fracture for the past six years. She was referred to the Philippine General Hospital for recurrent severe leg pains which occurred usually at menstrual mid-cycle. This condition was associated with lateral bowing of the proximal part of the right thigh, widening of the right hip region, and shortening of the right lower limb also known as Shepherd's Crook deformity. She also had café-au-lait spots at the back of her left legs and buttocks. Skeletal survey showed radiolucent medullary expansile lytic lesions with ground glass appearance of the right femur, tibia, fibula, humerus, scapula, pubis, ischium, carpal and metacarpal bones. Patient was noted to have short stature with height of 142 cm. Arm span was 139 cms, upper body segment (crown to the coccyx) was 70cms while lower body segment (coccyx to heel left foot) was 72 cms. The difference between the left and right leg was 7 cms. Mean parental height was 160 cm. She was then referred to the Endocrinology service of this institution for evaluation of the short stature and associated endocrinopathies. On review, she had adrenarche at 8 years old followed by menarche at 10 years old. She had no goiter. She had no cushingoid features. Patient had irregular menstrual cycles with oligomenorrhea (cycle: 60-180 days). Breast development and pubic hair were staged Tanner 5. In the approach to short stature where height age is less than either the bone age or chronological age, constitutionaldwarfism, hypothyroidism, growth hormone deficiency and fibrous dyplasia must be ruled out. Constitutional dwarfism was ruled out with a midparental height of 160 cm. A normal free thyroxine (17, normal: 9-23 pmol/L), thyroid stimulating hormone (2.4, normal: 0.25-4 ulU/ml) ruled out hypothyroidism, and a normal IGF-1 (103, normal: 91-223 nmol/L) ruled out growth hormone deficiency. This left us with the consideration of fibrous dysplasia of the bone which was consistent with the earlier radiographic findings. The combination ofpolyostotic fibrous dysplasia and café au lait spots led to the impression of McCune Albright Syndrome. The most common endocrinopathy associated with McCune Albright Syndrome is a peripheral hyperfunctioning ovaries which also harbors the G-protein mutation. This was evident in our case with a high estrogen (655.8, normal: 50-250 pg/ml) and suppressed LH (1.2, normal: 1.5-5 pg/ml) and FSH (3, normal 3.5-12.5 pg/ml) with a transrectal ultrasound finding of a 2.6 x 1.7 x 1.6 cm cyst at the right ovary. This precipitated the precocious puberty andearly closure of the epiphyseal plates resulting to short stature. To screen for other endocrinopathies, a 24 hour urine free cortisol (44, 20-90 ug/day), serum prolactin (15ng/ml, normal: 0-30ng/ml), free thyroxine (17, normal: 9-23.2 pmol/L) and parathyroid hormone (13.9, normal 10-65pg/ml) was documented and ruled out associated hypercortisolemia, prolactinoma, hyperthyroidism and hyperparathyroidism respectively. The patient had no history of change in shoe size, and no coarsening of facial features that was suggestive ofacromegaly. TREATMENT: Pat ient underwent bone graf t ing and osteotomy to correct the shepherd's crook deformity. Three cycles of intravenous pamidronate infusion in three consecutive days was given prior to the operation. Postoperatively, patient tolerated the procedure and was discharged after three days.OUTCOME: Shepherd's crook deformity was successfully corrected. Patient still had limp but with no pain and no new fractures for almost a year already. At present she is maintained on alendronate 70mg 1 tab once a week and calcium 1 gram per day.CONCLUSION: We repor t a case of McCune Albright Syndrome presenting with bone deformity which was later diagnosed to be fibrous dysplasia with polyostotic involvement, and was successfully treated with initial intravenous bi sphosphonates maintained on oral bisphosphonates following a surgical procedure to correct the shepherd's crook deformity. At present, she has had no new fractures.