Orbital cellulitis is an infection of the orbital soft tissues posterior to the orbital septum that presents with rapid progressive ophthalmoplegia, proptosis, swelling of the eye, chemosis, decrease in visual acuity, orbital pain and redness of the eyelid [2].
In the majority of patients, it occurs as a direct extension of infection of the paranasal sinuses, but haematogenous spread of bacteria or direct inoculation by trauma or surgery is also possible [3–5]. Sometimes, a dental focus is the underlying cause [6].
The clinical signs, laboratory abnormalities and the presence of a potential dental focus in this patient were suggestive of an infection, i.e. orbital cellulitis. The orbital apex, cavernous sinus and superior orbital fissure are contiguous structures, which may be affected by a number of conditions (inflammatory, infectious, neoplastic, iatrogenic/trauma, vascular) [7].
Depending on the cranial nerves involved and anatomic areas affected, different syndromes can be described:
-
1.
superior orbital fissure syndrome (cranial nerves III, IV, V1, VI),
-
2.
orbital apex syndrome (cranial nerves II, III, IV, V1, VI),
-
3.
cavernous sinus syndrome (cranial nerves III, IV, V1, V2, VI).
This classification is only of theoretical importance since the close relation between the mentioned anatomical areas causes a rapid and significant clinical overlap in the presentation of pathological entities.
In light of the symptoms of the described patient (involvement of cranial nerves V1 and V2), pathology affecting the cavernous sinus requires special attention as cavernous sinus thrombosis can occur secondary to orbital cellulitis when infection passes posteriorly through the ophthalmic veins. It can begin unilaterally, but will soon progress to become bilateral, and the patient’s state of consciousness is often impaired. MRI scanning can and did exclude this condition [8]. The osseous destruction seen on the CT scan led us to suppose the presence of an aggressive or long-standing infectious condition (e.g. mucormycosis) or malignancy (e.g. lymphoma). This fact was not completely appreciated at first due to the patient’s acute presentation. Rhino-orbito-cerebral mucormycosis is an aggressive fungal infection that occurs in immune-suppressed patients and presents with proptosis, visual loss and ophthalmoplegia among other symptoms [9]. On CT scanning, bony destruction is often encountered and a definite diagnosis can be made on histopathology [10].
Orbital cellulitis as the primary clinical appearance of a lymphoma has been reported in the literature before [11, 12]. The diagnosis of a plasmablastic lymphoma with regard to this is, however, unique. In this case, immunopathology revealed expression of CD45 and a weak expression of CD138 and CD79a. There was no expression of CD56, CD30, CD3, CD20 and CD10. Epstein–Barr virus-encoded RNA in situ hybridisation was positive. Plasmablastic lymphoma is a rare, AIDS-related, non-Hodgkin lymphoma with a noticeable predilection for the oral cavity [13]. This entity was first described by Delecluse et al. [14]. It carries a dismal prognosis with an average survival time of 6 months after diagnosis. At 13 months after diagnosis, our patient is still alive.
In retrospect, although there was an infectious component, the presence of the acute orbital symptoms in this case were most likely secondary to the lymphoma that was widespread to the skull base and orbit.
Yeh et al. presented a diagnostic algorithm for patients with findings consistent with an orbital apex syndrome [7]. Imaging should be performed in all cases, and MRI scanning is considered being superior to other imaging modalities. When inflammatory or infectious disease is suspected, proper laboratory tests should be conducted as well. Obtaining material for histopathological analysis may be required to arrive at a definite diagnosis.
On the basis of this case report, plasmablastic lymphoma may be added to the list of differential diagnoses of orbital cellulitis.