Why “orbital pseudotumour” is no longer a useful concept
- Department of Ophthalmology, University of British Columbia, 2550 Willow Street, Vancouver, British Columbia, Canada, V5Z 3N9
After 20 years of experience and more than 3000 orbital cases, one of the single most frustrating aspects of a referral based practice in orbit is the avidity ophthalmologists have for the diagnosis “orbital pseudotumour” and the laxity of clinical evaluation caused by misunderstanding this antiquated concept. If one looks at the historic trends in medical understanding, the last century was dominated by the clinical definition of disease, which gradually gave way in this century to specific diagnoses based on pathological, anatomical (imaging), and systemic associations of disease. The final decades of this millennium have been characterised in medical diagnostic sciences by increasing specificity brought about by immunopathological and molecular genetic techniques, which clearly will link to prevention and specific treatment based on the ultimate pathogenesis of disease. It is against this background that I disparage the use of the term “orbital pseudotumour” since its definition is of such diverse character that it no longer serves a useful purpose. In fact, its use contributes to intellectual laxity in clinical analysis and may have significant negative consequences as a result of delay and confusion in diagnosis and management of patients.
The term was put forward at the turn of the century by Birch-Hirschfeld as a negative entity when on surgical exploration of the orbit no distinct tumour was found.1 The confusion caused by this definition is compounded by the wide variety of pathological entities that have been included in subsequent years.2 3Historically, under the rubric “pseudotumour,” descriptions have included entities that affect different anatomical structures in the orbit, such as the muscles, lacrimal gland, periosteum, optic nerve, etc, and the clinical disorders described range from acute inflammations to asymptomatic, infiltrative, and non-infiltrative masses.3-5 The so called histological features may be simulated by a wide range of different …
