Bone mineral density in survivors of childhood brain tumours.

BACKGROUND: Osteopenia has been reported in children surviving acute lymphoblastic leukaemia, apparently as consequence of therapy. Few studies have been published on bone mineral density (BMD) evaluation in children surviving from brain tumours. The endocrine system in these patients is frequently affected as consequence of therapeutic interventions such as cranial irradiation and anti-neoplastic agents: growth hormone deficiency is the most common adverse sequel. The pathogenesis of osteopenia in brain cancer survivors is multi-factorial but still uncertain. OBJECTIVE: The aim of this study is to examine bone mass in 12 brain cancer survivors and its relationship with their hormonal status. RESULTS AND DISCUSSION: We observed that most of the patients had a BMD that was lower than normal in both the lumbar column and in the femoral neck. Bone mass loss was higher in the lumbar region rather than in the femoral neck, due to spinal radiation therapy and to the effect of hormonal deficiencies. Particularly hypogonadism, but also multiple hormonal deficiencies, are associated with lower BMD values. Experience in clinical care of these patients suggests the importance of periodic evaluations of BMD, especially in those with secondary hormone deficiencies. Moreover, the periodic assessment of the hypothalamus-pituitary function is essential for an early diagnosis of hormonal insufficiency, primarily hypogonadism, to precociously detect bone mineral loss and to prevent pathological fractures, thus improving the quality of life.

Gonadotropin-dependent sexual precocity in a boy affected by pseudohypoparathyroidism.

Pseudohypoparathyroidism (PHP) is characterized by hypocalcemia and hyperphosphatemia due to PTH resistance. PHP type Ia is due to diminished G(s)alpha activity in several tissues, causing resistance to hormones whose action is mediated by cAMP. Only two cases of males with PTH type Ia who paradoxically showed sexual precocity have been described in the literature. We describe an 11.5 year-old boy affected by PHP without AHO but with associated true precocious puberty, who came to the I.C.U. for tetanic seizures and drowsiness due to severe hypocalcemia. Hyperphosphatemia, increased PTH levels and normal 25-OH-vitamin D values were present. Skeletal X-ray showed mild osteopenia. Brain MRI revealed symmetric calcifications in basal ganglia and in frontal areas. Thyroid and thyreotropinic function were normal. Testosterone levels were in the adult range, as well as basal and stimulated gonadotropin levels. Tanner stage P4, G4; testicular volume 12-15 mi. Molecular cytogenetics studies are now underway to further elucidate the etiology of this form of PHP.