the clavicle is a rare site for bone tumours . according to the world health organisation
, the giant cell tumor is an aggressive potentially malignant lesion which means that its evolution based on histological features is unpredictable .
sites commonly affected by giant cell tumour are proximal tibia , distal femur and distal radius .
the oncologic patterns of clavicle resemble that of flat bones   and not other long bones . among tumors of clavicle ,
a 60  year old man presented to our department with pain and swelling over lateral end of left clavicle ( fig . 1 , fig .
the pain was insidious in onset , non radiating and had no diurnal variations and was aggravated on shoulder movements and relieved on taking medications .
we got a plain radiograph which revealed which an expansile radiolucent lesion arising from lateral end of left clavicle ( fig .
3 ) . the swelling demonstrated geographic type destruction without any soft tissue component or periosteal reaction .
4 ) . to aid in the diagnosis fine needle aspiration cytology was done which revealed a predominantly cellular lesion having sheets of plump , oval mononuclear cells with mild pleomorphism .
the cells had moderate cytoplasm , oval to elongated nucleus with moderate anisokaryocytosis with irregular nuclear membrane . amongst these cells , many multinucleated giant cells were also which were distributed evenly .
the differential diagnosis which were kept in mind are aneurysmal bone cyst , non ossifying fibroma , eosinophilic granuloma and tuberculous osteomyelitis .
since the clavicle does not necessary require reconstruction and the patient was a retired school teacher , not engaged in any physical work so surgical resection of the tumor was planned .
after proper investigations and pre anaesthetic clearance , a wide excision of the mass along with 3  cm of the healthy tissue was done ( fig .
the excised mass was sent for histopathological examination which also confirmed it to be a giant cell tumor .
the range of motion of the left shoulder was normal and post operatively there was no neurovascular deficict .
the patient was happy with the surgical outcome and at 1  year follow up there was no evidence of recurrence or metastasis .
. primary bone tumors of the clavicle are more likely to be malignant than benign ,   and amongst these tumors which occur in clavicle , giant cell tumor is a rare entity .
the differential diagnosis of giant cell tumor of clavicle which pose a diagnostic challenge both for the surgeon and the histopathologist are primary aneurysmal bone cyst , non ossifying fibroma.eosiniphilic granuloma and tuberculous osteomyelitis .
giant cell tumor is basically a cellular lesion made up of sheets of plump mononuclear cells with mild pleomorphism .
the cells have moderate amount of cytoplasm , oval to elongated nuceuswith moderate anisokaryosis with irregular nuclear membrane and 01 nucleolus . amongst these cells
are multinucleated giant cells distributed in a regular fashion.no collagen formation , no new bone formation or no necrosis is usually seen .
giant cells in abc are smaller as compared to giant cell tumor and their arrangement is loose with collagen formation .
histologically it has histiocytes loaded with lipid and hemosiderin and spindle cells arranged in storiform or whorled pattern and there is presence of collagen fibres .
eosinophilic granuloma has diagnostic langerhans cells and also it has large number of leucocytes , fibroblasts , plasma cells and lymphocytes .
curettage remains the main stay of treatment for giant cell tumors but for giant cell tumors occurring in expendable bones like distal ulna , iliac wing or proximal fibula , en bloc resection is performed without any reconstruction . after extensive search of literature
it was found that there are very few case reports describing giant cell tumors of clavicle , , . due to the paucity of the available literature
no definite treatment guidelines are available on the management of giant cell tumor of clavicle .
some authors   reported not so favourable outcomes after total claviculectomy due to pain , loss of muscle strength and dropping of shoulder . while some authors established that total or subtotal excision of clavicle
was rarely associated with loss of function . based on their reports we also performed partial claviculectomy and at one year follow up , patient was well satisfied with
the clavicle is a rare site for bone tumors and shares its oncological behavior with that of flat bones rather than long bones .
we have reported this case to emphasize the fact any expansile lytic lesion occurring in the lateral end of clavicle should be taken seriously and the diagnosis can be easily missed both clinically and radiographically if the clinician is not aware of the wide array of differential diagnosis which range from an infectious etiology like tuberulous osteomyelitis to a neoplastic etiology like giant cell tumour .
there seems to be a difference in opinion regarding functional outcome after claviculectomy for tumour like lesions of clavicle and our case report further highlights the fact the claviculectomy without any reconstruction seems to be a good option with no disability noted in long term .
since it is a single case report involving a single subject and we are not reporting the first case of this type in the literature , hence no approval was taken from the relevant ethics committee but written informed consent was taken from the patient to publish his details and clinical photographs .
written informed consent was obtained from the patient for publication of this case report and accompanying images .
a copy of the written consent is available for review by the editor - in - chief of this journal on request .
ak , kk and js contributed to the development of protocol and edited the manuscript  .
 highlightsgiant cell tumour of clavicle is a rare entity.the differntial diagnosis of giant cell tumour of clavicle which pose a diagnostic challenege gor both surgeon and histopathologist are aneurysmal bone cyst , non ossifying fibroma , tubercular osteomyelitis and eosniophilic granuloma.claviculecomy is a good option with no disability noted at long term . 
Introduction
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Discussion
Conclusion
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