Background: Cooper first reported giant cell tumors (GCT) in the 18th century. The clavicle is a rare site for tumors. Metastatic tumors are more common than benign. This is the first case of GCT lateral end of clavicle to be reported in the literature.
Case Reports: A 30-year-man was admitted with a 1-year history of progressively increasing swelling and pain over the left lateral end of the clavicle.
The plain radiograph and PET scan revealed an expansile radiolucent lesion in the lateral end of the clavicle. Swelling was epiphsio-metaphyseal in location. It demonstrated geographical type of destruction with a narrow zone of transition. There was no periosteal reaction or soft-tissue component. The mitotic activity was found to be 0-1/10 HPF. Diagnosis was confirmed histopathologically. A wide excision of the mass, including 3 cm of healthy tissue of the clavicle, was performed.
Conclusions: The presence of an expansile lytic lesion of the lateral end of the clavicle should be taken seriously and complete radiological and histopathological investigation should be done and giant cell tumor of the bone should be kept in mind despite its rarity.

Keywords: swelling, expansile lytic lesion, giant cell tumour, Clavicle