An update on mesenchymal tumours of the orbit with an emphasis on the value of molecular/cytogenetic testing

• Main Authors: F. Roberts, E.M. MacDuff
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2018-01-01
• Series: Saudi Journal of Ophthalmology
• Online Access: http://www.sciencedirect.com/science/article/pii/S1319453418300535

Mesenchymal tumours of the orbit are uncommon. Beyond childhood primary sarcomas are extremely rare and the literature is limited to case reports and short case series. However there is a diverse assortment of benign and malignant soft tissue tumours that may involve the orbit. Techniques to identify tumour specific cytogenetic or molecular genetic abnormalities often resulting in over- expressed proteins are becoming an increasingly important ancillary technique for these tumours. This review focuses on 3 specific areas: 1. Orbital mesenchymal tumours where cytogenetics are important to reach the correct diagnosis. The majority of these are chromosomal translocations that often result in a fusion gene and protein product; 2. Orbital mesenchymal tumours where cytogenetics are important to identify patients who will do well versus those with a poorer prognosis. This is turn helps with therapeutic options. In some tumours e.g. synovial sarcoma the chromosomal translocations can occur with 2 different regions resulting in different fusion products that carry a different prognosis. Alternatively whilst the majority of alveolar rhadomyosarcomas are fusion positive a minority are fusion negative with a better prognosis; 3. Orbital mesenchymal tumours where the identification of specific cytogenetic abnormalities has resulted in overexpression of specfic proteins which are diagnostically useful biomarkers for immunohistochemistry. Keywords: Cytogenetics, Molecular genetics, Mesenchymal tumour, Soft tissue tumour, Orbit