Exophytic giant-cell tumor of the tibial tubercle.

A 23-year-old pregnant woman presented to the orthopedic tumor clinic with gradual onset of left anteriomedial tibial pain for one month and a lytic lesion of the proximal tibia on radiography. MRI showed an exophytic mass of the left tibial tubercle with fluid-fluid levels. The patient underwent surgical excision, and pathology was consistent with giant-cell tumor.

Single dose of a dopamine agonist impairs reinforcement learning in humans: behavioral evidence from a laboratory-based measure of reward responsiveness.

Rationale: The dopaminergic system, particularly D2-like dopamine receptors, has been strongly implicated in reward processing. Animal studies have emphasized the role of phasic dopamine (DA) signaling in reward-related learning, but these processes remain largely unexplored in humans.

Objectives: To evaluate the effect of a single, low dose of a D2/D3 agonist--pramipexole--on reinforcement learning in healthy adults.