Age / Sex : 22 / F

22/F

C.C.: Frequent headache for 3 years, and muscle twitching since childhood, Short stature, mental retardation (Click to enlarge)

pseudohypoparathyroidism (Albright's hereditary osteodystrophy)

Discussion

Findings:
1) Radiologic Findings: - Soft tissue calcification, brachydactyly and short metacarpals and metatarsals - Calcification in the cerebellum, basal ganglias and subcortical white matter
2) Bone scan : - Increased vascular perfusion on the right calf, and delayed uptake on the left ankle.

Differential Diagnosis:
- Pseudohypoparathyroidism or Pseudopseudohypoparathyroidism, Hypoparathyroidism
- Positive metacarpal sign : Pseudohypoparathyroidism, Pseudopseudohypoparathyroidism, Turner's syndrome, basal cell nevus syndrpme, multiple epiphyseal dysplasia

Diagnosis: Pseudohypoparathyroidism (Albright's hereditary osteodystrophy)
* Laboratory findings : calcium 6.9 ~ 7.8 mg/dl, phosphorus 6.3 ~ 6.8 mg/dl, ionized calcium 0.87 mmol/l, ALP 160 IU/L, PTH-I 114.5 pg/ml
* Radiographic features of the pseudopseudohypoparathyroidism are identical to those of pseudohypoparathyroidism, except that basal ganglia calcification is relatively rare.

Discussion:
1. Pathogenesis: end organ resistance to the action of parathyroid hormone.
2. X-linked dominant trait, women > men, usually diagnosed in the 2nd decade
3. Clinical findings - Characteristic somatotype : short stature, obesity, round face and brachydactyly - Additionally abnormal dentition, mental retardation, strabismus, dermatoglyphic abnormalities, impaired taste and olfaction, tetany, convulsion, cramping of the extremities, hyperexcitability, stridor
4. Laboratory findings. - Hypocalcemia, hyperphosphatemia, diminished phosphaturia, Excessive secretion of parathyroid hormone
5. Radiographic findings. Soft tissue calcification and ossification – plaque like, asymmetrically distribution Basal ganglia calcification Premature physeal fusion – pseudoepiphyses, reduced carpal angle Metacarpal and metatarsal shortening – predilection for 1st and 4th digits (Positive metacarpal sign) Calvarial thickening Exostoses – central location, right angle projection Abnormalities of bone density – increased, normal, decreased Bowing deformities, spinal stenosis * Pseudopseudohypoparathyroidism : normocalcemic form of pseudohypoparathyroidism * Pseudohypohyperparathyroidism : renal unresponsivenenss to parathyroid hormone and normal osseous response to the hormone. Radiographic abnormalities of hyperparathyroidism (subperiosteal resorption, brown tumor, osteoslcerosis, periosteal neostosis, slipped capital femoral epiphysis)

References:
Resnick D, Krandorf MJ ed. In Bone and joint imaging. 3rd ed. Elsevier Saunders 2005:617-621.