An 18-year-old male, college student from Malaysia presented with a small swelling measured 8 mm × 10 mm at his left lower tarsal conjunctival for one year duration. There is no history of eye pain, redness, or visual disturbance. No history of eye trauma or previous eye surgery. After one year, the patient felt slight discomfort arising from the lesion and sought treatment from ophthalmology clinic. An excision biopsy was performed and histopathological examination confirmed a clear cell sarcoma (CCS). Margins of excision were clear and magnetic resonance imaging (MRI) of the orbit did not reveal any intraorbital extension. Other common malignancy such as squamous cell carcinoma or conjunctival intraepithelial neoplasm was excluded.

However, eight months after the excision, the patient noticed reappearance of a swelling at the same site. Then he was referred to oculoplastic surgery subspeciality for further management. On examination, the vision was 6/9 and 6/12 for right and left eye respectively. There was a cystic lesion seen at the lower conjunctival of the left eye which measured 8 mm × 3 mm. The lesion was mobile and non-tender with a well-defined margin (Figure 1). There was no dilated tortuous vessels seen and no discharge and bleeding noted. External eye examination did not reveal any abnormality. Examinations of cornea, pupil, lens, and fundus were unremarkable. Intraocular pressure was normal for left eye. Examination of right eye did not reveal any abnormal findings.

In view of the progress and findings, a clinical diagnosis of recurrence CCS of the left conjunctival was established. He underwent left excision biopsy and frozen section guidance under local anesthesia. Intraoperatively frozen section revealed clear margin of excision. Histopathological examination confirmed recurrence CCS of the left conjunctival (Figure 2 and Figure 3). Further staining by immunohistochemical staining using HMB 45 (Figure 4A), Melan A, (Figure 4B), and S100 (Figure 4C) reveled positive result for CCS. Postoperatively the patient recovered well without any complication. Till date he remains asymptomatic and well (Figure 5).

Clear cell sarcoma (CCS) is a very rare malignancy, less than 1% of all soft tissue tumors arising from the soft tissue and dermis [1],[2]. This malignancy commonly affects young adults between 20 and 40 years old. It can arise from gastrointestinal tract, dermis layer of the skin, or any part of the trunk [3]. This condition reported slightly more common in females than in males [1]. Clear cell sarcoma, also known as translocation-associated sarcoma, is caused by a genetic mutation.

Clear cell sarcoma is classified either by the location or genetically. If by location, it commonly affects tendon and aponeuroses as one group, gastrointestinal and cutaneous are the remaining categories. If by genetic classification, it is EWSR1/ATF1 or a EWSR1/CREB1 translocation, while some tumors may not have any EWSR1 translocation [1],[2].

Majority of the CCS are asymptomatic at the early stage. The common presentation is a slow growing lump. Over period of time, if the tumor erodes into important structure such as tendon, muscles, or nerve then symptoms may start to appear. Constitutional symptoms such as appetite loss, lethargy, or fever are usually late.

Histologically CCS composed of monotonous epithelioid and spindle cells with clear to eosinophilic cytoplasm characterized by melanocytic differentiation and EWSR1-ATF1/CREB1 rearrangement [2]. Immunohistochemically, these tumor cells positively stain with S100/SOX10+, Melan A+, HMB45+ [2],[4].

Tumors arising from conjunctiva that have been reported are carcinoma, melanoma, lymphoma, and Kaposi’s sarcoma [5],[6].

There was no reported case of CCS of the conjunctiva in the past. This may be the first one. The patient had very minimal symptoms thus it led to delayed diagnosis only after eight months of initial presentation. Despite the initial excision, the tumor recurred after a duration of one year at the same location. Therefore, it is very important to ascertain the margin of excision is adequate, thus intraoperatively frozen section specimen to send for histopathological examination is crucial as demonstrated in this case to ensure a clear margin of surgical removal of the tumor.

This tumor is a slow growing type, there is no previous report published on distance metastasis of the tumor. Nevertheless, local extension is possible, therefore CT or MRI imaging of the orbit to look for any possibility of tumor extension is necessary.

The patient remains asymptomatic and healthy. However, a longer duration of follow-up is necessary in view of the past history of recurrence and there was no previous published report on median duration of recurrence for this tumor.

This case illustrated a very rare ocular condition. There was no reported case of clear cell sarcoma of the conjunctiva in the past and this may be the first one. A longer duration of follow-up is necessary in view of the past history of recurrence and there was no previous published report on median duration of recurrence for this tumor.