P60 | Osteopoikylosis and secondary hyperparathyroidism: an unusual association of rare diseases

Background: Osteopoikilosis (OPK) is a rare bone disease with a prevalence of 1/50,000. It’s usually diagnosed incidentally by radiographic examinations. The etiopathogenesis is still unclear. In Literature OPK is described as frequently associated with disseminated lenticular dermatofibrosis, achondroplasia and vitiligo, meloreostosis, sacral cleft, peripheral vascular disorders, lentiginosis. Case report: A 50 year old male, presented, as outpatient, in our Clinic, for abdominal pain. His medical history was negative for chronic conditions except obesity. Abdominal x-ray revealed unexpected multiple osteolytic lesions in pelvic bones and both femoral heads, suggestive for malignancies. A total body CT scan, instead of neoplasms, revealed osteopenic benign multiple structural alterations of the bone matrix, suspected for Osteopoikilosis. Laboratory tests showed increased PTH (115 pg/ml), normocalcemia (8.4 mg/dl), hypercalciuria (378 mg/24h), hypovitaminosis D (19 ng/ml), no alterations in renal function. The bone densitometry was normal. Therefore, after excluding primary hyperparathyroidism, secondary hyperparathyroidism due to idiopathic hypercalciuria, associated with OPK, were diagnosed. Conclusions: OPK and secondary hyperparathyroidism due to idiopathic hypercalciuria are both rare diseases and their association was, surprisingly, never described first in Literature.