Diagnostic challenge: Diffuse large B-cell lymphoma masquerading as orbital cellulitis

Introduction

Orbital cellulitis is a soft tissue infection occurring posterior to the orbital septum. ¹ In most cases, it occurs as a direct extension from a paranasal sinuse infection. A unilateral eyelid swelling and redness may thus initially be diagnosed as orbital cellulitis. However, lack of response to an intensive course of antibiotics combined with suspicious features on endoscopy and orbital imaging should alert physicians to a diagnosis of DLBCL.

Case report

A 72-year-old man with underlying leprosy presented with a one-week history of swelling and redness of his right eye. The swelling progressively increased in size, extending to the nasal bridge accompanied by decreasing vision and eye pain for two days. The left eye was blind of long-standing corneal decompensation secondary to pseudophakic bullous keratopathy following a complicated cataract operation.

At presentation, right vision was 6/60. The right eye was proptosed with swollen and erythematous eyelids. Extra-ocular muscle movement was restricted in all gazes with lagophthalmos exposing the inferior cornea. The conjunctiva was injected and chemosed. The medial canthus was also swollen and erythematous with extension to the nasal bridge. Fundoscopy assessment was unremarkable and no sign of infection was seen. The left cornea was opaque with band keratopathy. The left eye had a large angle exotropia (Figure 1). Anterior and posterior segment details were not visible in the left eye.

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Figure 1.

Patient presented with features of right eye orbital cellulitis.

A clinical diagnosis of right orbital cellulitis was made and intravenous rocephine 2 g bd was commenced. Computed tomography scan of the orbit showed a non-liquefied abscess or possible tumour in the right orbital region with local infiltration and adjacent osteomyelitic changes. There was also some fullness seen in the right postnasal region. An endoscopy revealed the right middle meatus to be filled with friable tissue and covered by pus (Figure 2). The endoscope could not be advanced further owing to the obstruction by the mass.

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Figure 2.

Nasal endoscopic assessment revealed friable mass after pus removal.

Although the patient claimed that his pain had lessened, there was in reality not much improvement clinically over the ensuing few days. Owing to this and the suspicious radiological and endoscopic findings, a right functional endoscopic sinus surgery and orbital decompression was planned. Intra-operatively, the mass was seen occupying the right maxillary sinus, anterior and posterior ethmoidal sinus. Infiltration was noted involving the right middle and inferior turbinate. Tumour debulking was done and the intraconal tumour was removed in the same sitting. Histopathology reported features in keeping with DLBCL.

He was then started on chemotherapy resulting in a significant reduction in tumour size, notable on CT scan. The third subsequent cycle of chemotherapy, however, was interrupted by a hospital acquired pneumonia, from which he succumbed.

Discussion

DLBCL is the most common high-grade non-Hodgkin lymphoma, contributing to 30–40% of all non-Hodgkin lymphomas. ² DLBCL is more prevalent in the elderly population, although it may also be seen in young adults and rarely in children. DLBCL has a slight male predominance. Clinically, most patients present with a rapidly growing tumour mass involving one or more lymph nodes or extranodal sites.

Chronic stimulation of the lymphoreticular system seen in leprosy is believed to be a predisposing factor for malignant transformation. ³ Lymphoreticular malignancy occurs with unusual frequency among the immunosuppressed. ³

Although 40% of patients presenting with extranodal disease have gastrointestinal tract involvement, the second most common site is in the orbit.^2,4,5 Almost all patients have unilateral ocular adnexal region involvement. ⁶