Paediatric orbital alveolar soft part sarcoma recurrence during long-term follow-up: a report of 3 cases and a review of the literature

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a clinically and morphologically distinct malignant soft tissue tumour. It occurs mostly in the lower extremities in adults. The purpose of our study was to describe the related clinicopathologic factors, treatment and prognosis of recurrent orbital ASPS in children. CASE PRESENTATION: Three children aged from 1 to 12 years presented with unilateral proptosis, restricted ocular motility and impaired visual acuity of the affected eye. Periodic acid Schiff (PAS) -positive diastase-resistant crystalline granules were found in all cases. Immunostaining of TFE-3, INL1 and Ki67 was positive in the tumour cells of two patients. The time until local recurrence of primary tumor in patient 2 and patient 3, who only underwent tumour resection, was shorter than that of patient 1, who underwent tumour excision and postoperative radiotherapy. The recurrent masses were successfully treated with complete tumour excision followed by adjuvant radiotherapy. Patient 1 presented metastasis at 11 years after radiotherapy. CONCLUSIONS: Orbital ASPS in children is easily misdiagnosed due to its rare occurrence and atypical clinical findings. Early diagnosis with multidisciplinary, complete surgical resection combined with adjuvant radiotherapy is essential for achieving long-term disease-free survival in orbital ASPS patients.