Abstract
We present a case of an intra-orbital, subperiosteal organizing hematoma (pseudocyst) which was referred to our clinic with a misdiagnosis of an orbital epidermoid cyst. This confounding lesion caused a great deal of debate following a magnetic resonance imaging (MRI) scan. It was only after surgery and investigating that the patient remembered an incident with orbital trauma nearly 2-years prior. We used existing literature to hypothesise that this lesion has a spectrum of presentations readily reported, but poorly presented. Histo-pathologically it seems feasible that this lesion progresses from an acute intra-orbital subperiosteal haemorrhage, to an organizing hematoma with associated scar tissue (pseudocyst) which would eventually develop into a chronic hematic (blood) cyst.
Highlights
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Multi-disciplinary communication is key to best clinical practice.
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Hematic Cyst, Orbital Hematoma, Organizing Orbital Hematoma – is it a spectrum of the same entity?
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Extraconal retrobulbar haemorrhage can arrest and ‘linger’ asymptomatic for longer periods than expected.
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CT scans sometimes need to be bolstered with a MRI scan in the head & neck, especially when in doubt.
1
Introduction
A persistent accumulation of blood in the orbital cavity that would form a benign lesion either spontaneously or associated with a history of trauma is not uncommon, but its pathogenesis remains vague. We are referring to a lesion that is an accumulation of hematogenous debris that at first gets surrounded by a fibrous tissue wall which initially lacks an epithelial lining that is not related to local malformation of cells and that is not a neoplasm of local tissue abhorrent growth. These lesions have been referred to in the past as a subperiosteal orbital hematoma, an organizing hematoma, a hematic cyst, a haematocele, a blood cyst, and a ‘chocolate cyst’ [ ]. When we encountered this entity clinically, nearly all literature we came across reported it as a misdiagnosis with other benign or malignant orbital processes. This is due to a poor definition in literature which demonstrated a need for uniformity of terminology and for a more precise explanation on how these lesions form, and how they develop a mechanism that leads to gradual expansion and manifestation of sign & symptom.
Following our case report, we postulate ( Fig. 1 ) that it is most likely a progression of an acute sub-clinical orbital haemorrhage that develops a pseudo-lining with time, creating granulation tissue (pseudo-capsule) with foreign-body giant cells and eventually progresses to a ‘growing’ true cystic lesion (with an epithelial or endothelial lining), a process not to dissimilar to how a chronic subdural hematoma (CSH) forms [ ]. These are called hematic cysts which have been described in association with various diseases.
Shapiro et al. [ ] found hematodin crystals (pigment closely related to bilirubin) in these lesions which are also found after an old haemorrhage [ ]. When intra-orbital haemorrhage occurs whether due to trauma or spontaneously, in most cases the blood is absorbed without cystic formation if no surgical intervention was needed. If it does not get absorbed, it organises into a hematoma and remains subacute and asymptomatic until it is either found incidentally or develops symptoms due to a progressively increasing mass effect from scar tissue or an expanding cyst. Yoshikawa et al. [ ] further postulated on how these cysts gradually expand also similarly like a CSH, which may be due to hyperfibrinolysis resulting from over-secretion of tissue-type plasminogen activator (tPA) from the endothelial cells in the wall lining [ ].
2
Case
A 48-year-old mildly hypertensive Arab male presented to our maxillofacial department with mild left orbital pain and a ‘feeling of fullness’ with no obvious ocular signs. He woke-up 72-h previously with a dull, left-sided headache and mild left orbital discomfort. Over the next 24-h, he experienced progressive symptomatic diplopia and mild orbital discomfort on right and upward gazes. He stated that he developed ‘mild double vision’ the last year, but since it was ‘not bothering him much’, he never attended hospital for it. On this initial visit he reported no history of trauma, no recent aggressive Valsalva manoeuvre, and no history of sinus disease. As a matter of fact, he only later recollected an incident of trauma over 2-years previously in which he developed a ‘black-eye’. This was later confirmed with the emergency department that verified his story.
On ophthalmological review, visual acuity was within normal in both eyes. Intra-ocular pressure (IOP) was 12 mm Hg in the right eye and 15 mm Hg in the left eye. No afferent pupillary defect was noted. Visual fields & colour were full and unaffected. Dilated fundus examination was within normal, without choroidal folds or optic nerve oedema.
A contrast enhanced computerised tomography (CT) scan showed a 2 cm × 3 cm x 1cm oblong shaped well circumscribed hypodense mass in the medial side of the left orbit which was extraconal in location situated between the medial rectus muscle with the lamina. Mucosal thickening of the adjacent sinus was noted. The medial rectus muscle was smoothly deviated laterally, and mild enhancement of the wall was also seen. A magnetic resonance imaging (MRI) scan showed heterogeneous hyperintensity on both T1 & T2-weighted images with no evidence of fat separation ( Fig. 2 and 3 ).
