Acromegaly and proximal femoral fracture in an aged person: Bone histomorphometry, vitamin D metabolites and parathormone

Osteoporosis and fractures are rare in acromegaly. An 84-year-old acromegalic woman sustained a fractured neck of femur in a fall. Histomorphometric analysis of an iliac crest biopsy showed marked osteoporosis and augmented resorption parameters. Cortical plates were very thin and bone volume was 8.5%; 12.5% is the reference value for women at this age. The total resorption surfaces were 23.7% compared with the reference value of 8%. We conjecture that postmenopausal and involutional osteoporosis were far advanced before the development of acromegaly, explaining the coexistence of the two conditions. Parathormone (65 pmol/l) and 23,25-dihydroxyvitamin D (1.34 ng/ml) levels were within normal limits, but those of 25-hydroxyvitamin D (5.6 ng/ml) and 1,25-dihydroxyvitamin D (15 pg/ml) were markedly decreased.