This is a retrospective case series study from Melbourne, Australia, of 93 patients with extraocular muscle (EOM) enlargement who underwent an EOM biopsy between March 1992 and January 2017. Statistical analysis was performed to compare the data between patients with malignant and benign biopsies, clinical, radiological and histopathological information were retrieved from the medical records. Forty-eight (52%) were benign and 45 (48%) were malignant. Median age of subjects was 61.1 years; those with malignant pathology were significantly older (p<0.0001). A history of malignancy (p<0.0001) and diplopia (p=0.029) were significant factors in predicting malignancy. Pain and eyelid erythema (p=0.005 and p=0.001 respectively) were more likely in benign conditions and idiopathic orbital inflammation was the most common benign condition. Lymphoma was the most common malignancy. The authors recommended minimally invasive technique with low morbidity, to allow an accurate diagnosis and appropriate management for patients with a suspicion of malignancy or those who present or progress in an atypical manner.