British Journal of Radiology (2003) 76, 577-578
© 2003 British Institute of Radiology
doi: 10.1259/bjr/58320420
A case of unilateral enophthalmos
H D Roach, FRCR1,
G N Shuttleworth, FRCOphth2 and
N Powell, FRCR1
Departments of 1 Radiology and 2 Ophthalmology, Singleton Hospital, Sketty, Swansea SA2 8QA, UK
Correspondence: Dr Huw D Roach
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Introduction
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A 28-year-old woman, who was 37 weeks into an otherwise uncomplicated pregnancy, was referred to ophthalmology clinic because she had noticed that her right upper eyelid had become retracted when compared with the left. She experienced no other eye symptoms and reported no history of facial trauma or sinus disease. Her thyroid function was normal.
Physical examination revealed a deep right upper eyelid sulcus and 2 mm of enophthalmos. The eye was also depressed and displaced medially. Eye movements were however normal.
Further investigation with CT was performed after the birth of her child (Figure 1
).
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Figure 1. Unenhanced coronal CT images through (a) the orbits and (b) facial sinuses (slice thickness 5 mm; window width 1500 HU, window level +200 HU).
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What are the characteristic imaging features demonstrated and what is the diagnosis?
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Answer
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Unenhanced coronal CT images demonstrate complete opacification of the right maxillary sinus. The sinus itself is also smaller than the left. The orbital floor is depressed with associated downward displacement of the intraorbital structures (Figure 2a). There is also slight bony thinning compared with the left. The ostium of the right maxillary sinus is occluded by the uncinate process apposed to the medial orbital floor and the middle meatus is enlarged (Figure 2b).
In the absence of other symptoms, these features in a fully developed maxillary sinus are characteristic of "Silent Sinus Syndrome", the radiological features of which have recently been reviewed by Illner et al [1]. The diagnosis having been made, the patient was referred to an otorhinolaryngologist for consideration for endoscopic surgery.
The term Silent Sinus Syndrome was first used in 1994 by Soparker et al [2] to describe a subgroup of patients with spontaneous unilateral enophthalmos and hypoglobus associated with a small ipsilateral maxillary sinus, but no other symptoms. It is an uncommon condition probably more familiar to ophthalmologists and otorhinolaryngologists than radiologists.
Patients typically present to an ophthalmologist or otorhinolaryngologist for investigation of facial asymmetry, which can be interpreted as enophthalmos or ptosis of the affected eye or sometimes mistakenly as exophthalmos of the contralateral eye [3]. Other modes of presentation include transient vertical diplopia, lid retraction, lagophthalmos and blurred vision [4]. A history of significant sinus symptoms is typically absent, although patients sometimes give a history of remote episodes of sinusitis or upper respiratory tract infection [3].
The exact pathogenesis of the condition is not certain, but occlusion of the ostium and negative intrasinus pressure are likely to be instrumental [3, 5]. Chronic reduced intrasinus pressure leads to sinus atelectasis in a similar manner to middle ear atelectasis associated with chronic Eustachian tube obstruction [6].
Although the diagnosis is often made clinically, imaging with CT or MRI helps to exclude other causes of enophthalmos in the differential diagnosis such as orbital "blow-out" fracture, primary or secondary malignancy, orbital varices, microphthalmos, neurofibromatosis with absence of the sphenoid wing, connective tissue diseases and soft tissue atrophy [2, 6]. The imaging features are best demonstrated in coronal images.
Treatment is often by functional endoscopic sinus surgery to remove obstruction and restore sinus pressure [1, 4, 6]. The orbital floor can be repaired during the same operation or deferred to a later procedure [1]. The surgical outcomes are variable [1].
Received for publication May 20, 2002.
Accepted for publication June 6, 2002.
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References
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- Illner A, Davidson HC, Harnsberger HR, Hoffman J. The silent sinus syndrome clinical and radiographic findings. AJR Am J Roentgenol 2002;178:503–6.[Abstract/Free Full Text]
- Soparker CNS, Patrinely JR, Cuaycong MJ, et al. The silent sinus syndrome: a cause of spontaneous enophthalmos. Ophthalmology 1994;101:772–8.[Medline]
- Vander Meer JB, Harris G, Toohill RJ, Smith TL. The silent sinus syndrome: a case series and literature review. Laryngoscope 2001;111:975–8.[Medline]
- Wan MK, Francis IC, Carter PR, Griffits R, van Rooijen ML, Coroneo MT. The spectrum of presentation of silent sinus syndrome. J Neurophthalmol 2000;20:207–12.[Medline]
- Davidson JK, Soparker CN, Williams JB, Patrinely JR. Negative sinus pressure and normal predisease imaging in silent sinus syndrome. Arch Ophthalmol 1999;117:1653–4.[Free Full Text]
- Gillman GS, Schaitkin BM, May M. Asymptomatic enophthalmos: the silent sinus syndrome. Am J Rhinol 1999;13:459–62.[Medline]
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