(py'pÉ) Plural pupae (py'pÄ) An insect in the nonfeeding stage of development between the larva and adult, during which it typically undergoes a complete transformation within a protective cocoon or hardened case. Only certain kinds of insects, such as moths, butterflies, ants, and beetles, develop as larvae and pupae.
Usual interstitial pneumonia (UIP) is a form of lung disease characterized by progressive scarring of both lungs. The scarring (fibrosis) involves the supporting framework (interstitium) of the lung. UIP is thus classified as a form of interstitial lung disease.
UIP is therefore the pathologic counterpart of IPF. The term 'idiopathic' is used because the cause of pulmonary fibrosis is still unknown. IPF usually occurs in adults of between 50 and 70 years of age, particularly those with a history of cigarette smoking, and affects more men than women.