Temporal bone pathology of two infants with Larsen's syndrome.

Two infants who had multiple joint dislocations, unusual facies, and bony abnormalities, typical of the syndrome first reported by Larsen et al. (J. Pediatr., 37 (1950) 574-581) are described. This report expands Larsen's syndrome to include the following findings of temporal bone pathology. Case 1 (one year and 8 months old) showed dislocation of the malleus and incus, an abnormal foot plate, mesenchyme remaining in the attic and mesotympanum, poor development of the mastoid air cells, and poor development of the labyrinth. Case 2 (3 years and 6 months old) showed dislocation of the malleus and incus, mesenchyme remaining in the attic and mesotympanum, and an abnormal stapes. These histological findings suggest that a maldevelopment similar to that which occurs in the skeletal system occurs in the temporal bones as well as in the face and extremities including many joints.