The case of a woman suffering from progressive diaphyseal dysplasia is presented. Characteristic symptoms of crippling pain in both legs, severe aching in both forearms, and episodic temporofrontal and occipital headache were only partially regulated by corticosteroid treatment. However, pregnancy resulted in a progressive disappearance of these symptoms, allowing withdrawal of steroid treatment. Tc-99m MDP scintigraphy performed immediately after delivery showed a decrease of the intense uptake in the forearms, tibiae, and skull, which had been documented prior to pregnancy. However, widespread pain recurred within 6 weeks after delivery, accompanied by a recurrence of multiple severely hyperactive foci on bone scintigraphy. Alterations of immune modulated processes and changes in bone mineral homeostasis and in endogenous cortisol metabolism during pregnancy can be considered as possible explanations for the temporary improvement in clinical and scintigraphic signs of progressive diaphyseal dysplasia in this patient.