Patellar Instability: Imaging Findings.

Patellofemoral instability results from impaired engagement of the patella in the trochlear groove at the start of flexion and may lead to pain and lateral patellar dislocation. It occurs most frequently in adolescents and young adults during sporting activities. Trochlear dysplasia, patella alta, and excessive lateralization of the tibial tuberosity are the most common risk factors for patellar instability. The main role of imaging is to depict and assess these anatomical factors and highlight features indicating previous lateral dislocation of the patella.

Small Bowel Diverticulitis: An Unusual Cause of Abdominal Pain.

Teaching point: Small bowel diverticulitis, much less common than its colonic counterpart, is a diagnosis that must be considered in the presence of abdominal pain, especially in an elderly person.

Breast Metastasis: An Unusual Cause of Malignant Breast Lesion.

Teaching point: Although rare, an intra-mammary metastasis from extramammary cancer should be considered in a patient with an oncological history.