We identified 4 patients with primary clavicular ES at our center from June 2003-June 2009. Baseline workup included core needle biopsy of the tumor for confirmation of ES, CT scan or MRI of neck and chest, bone scan, and bone marrow biopsy. The patients received Neoadjuvant chemotherapy (NACT) with vincristine, actinomycin-D, doxo-rubicin and cyclophosphamide, alternating every 3 weekly with ifosfamide and etoposide [4]. Response to NACT was assessed clinically and by imaging (CT or MRI scan). The patients who responded to NACT underwent total clavicular excision after 9-12 weeks of initiation of NACT. Patients with residual tumor post operatively or positive surgical margins received radiotherapy to the local site. Adjuvant chemotherapy with drugs as used for NACT was administered for 48 weeks.

All 4 patients were non-metastatic at presentation and were females (median age 16 years, range 5-18 years). Pain and swelling were the predominant presenting manifestations with median duration of 4.2 months (range: 2-6 months). Two patients had received anti-tubercular therapy for presumed bone tuberculosis prior to presentation. There was no predilection for any site or side of clavicle. Biopsy in all four patients was morphologically consistent with a small round blue cell tumor which showed positivity for mic-2 (CD99) on immunohisto-chemistry. Reciprocal chromosomal translocation t(11;22) (q24;q12), could not be studied. All patients responded clinically and radiologically to NACT and underwent total clavicular excision (TCE) after 9-12 weeks of NACT. One of the 4 patients had a positive surgical margin and was administered local radiotherapy. After a median follow up of 21.5 months (range 10-37 months), 3 of our patients are in complete remission. One patient with negative surgical margin relapsed locally in the neck while on adjuvant chemotherapy and thereafter received palliative radiotherapy. Post TCE none of our patients had significant restriction of movement and did not require any reconstructive procedures.

We could identify only one earlier published cases series on clavicular ES [5]; three case series on clavicular tumors which also included ES patients [6-8] and two case reports describing clavicular ES [9, 10].

The reported male to female ratio for ES is 1.6:1; an interesting observation was that all our patients were females and overall 16/25 (64%) patients of non-metastatic ES of clavicle reported in the literature including ours were females. The median age of presentation of clavicular ES in reported literature including ours is 15 years (range: 10 months-33 years), this is similar to what has been reported for ES arising from all other sites [1]. Data on long-term outcomes and details related to chemotherapy are lacking amongst the published cases of clavicular ES.

Successful outcome in ES is dependent on prompt initiation of NACT followed by surgery and adjuvant chemotherapy with addition of radio-therapy if required. Patients with non-metastatic ES have an overall survival of 70-75% [1], currently 3/4 of our patients are alive and disease free. Survival in patients with metastatic ES is dismal and is less than 15-20% [1]. Good functional outcomes can be maintained after clavicular excision for clavicular tumors and reconstruction procedures are rarely required [5,7]. The majority of clavicular tumors in children and adolescents are malignant. Differential diagnosis of clavicular tumors in children and adolescents include osteosarcoma, chondrosarcoma Langerhans cell histiocytosis, lymphoma, malignant fibrous histiocytoma, osteomyelitis, osteochon-droma and aneurysmal bone cysts [6-8].

Patients with clavicular ES present late to the oncologist, due to the fact that ES is not suspected at this rare site. Most patients receive therapy for unrelated conditions like tuberculosis as was seen in two of our patients. Medical personnel need to be aware that ES does occur in the clavicle.

Contributors: VR and SB were both involved in collection of data, analysis, literature review and manuscript preparation; SR was involved in the surgical management of the patients.

Funding: None. Competing interests: None stated.