A 65-year-old diabetic male patient with abdominal diffuse large B-cell lymphoma (DLBCL) that had been treated with three cycles of chemotherapy (RCEOP regimen, incorporating rituximab, cyclophosphamide, etoposide, vincristine, and oral prednisolone), presented with sudden painless loss of vision in the left eye and headache for 3 days. There was no history of fever. On examination, pupillary reflex was absent in the left eye. Laboratory investigations revealed elevated blood sugar (291 mg/dL) and leukocytosis (43,000/mm3) with increased neutrophil count (absolute neutrophil count 41.5 × 106/mL).
Magnetic resonance imaging (MRI) of the brain and orbits revealed enhancing mucosal thickening in nearly all the paranasal sinuses [Figure 1a and b], suggestive of sinusitis. Left-sided proptosis was also observed. Fat stranding was noted in the left orbit, in the pre- and post-septal compartments [Figure 1c and d]. Minimal fluid was seen posterior to the globe. The medial rectus muscle showed T2 hyperintense signal, suggestive of edema. T2 hyperintense signal was also noted in the skin and subcutaneous tissue of the upper maxilla. Expansion of the cerebrospinal fluid (CSF) sheath surrounding the left optic nerve was noted with increased enhancement [Figure 2a], suggestive of optic neuritis. The optic canal was noted to be adjacent to the sphenoid and posterior ethmoid cells, as seen on the prior computed tomography (CT) examination of the paranasal sinuses [Figure 2b-d]. What is the diagnosis, and what should be done next? Once you have finalized your answer, read on.
Lymphomatous infiltration of the optic nerve
Imaging features on MRI for this entity include thickening and enhancement of the optic nerve along with associated soft tissue in some cases. Simultaneous disseminated central nervous system (CNS) disease can also be present on imaging. CSF examination may be positive for lymphocytes in these cases. However, biopsy is often required for confirmation.
Infective optic neuritis
Infective etiology needs to be considered in immunocompromised patients. Enhancement and thickening of the optic nerve can be seen on MRI. Imaging may even be normal in some cases. Adjacent infective processes in the orbit and paranasal sinuses can spread to the optic nerve. CSF examination may be helpful in identifying the causative organism.
Drug-induced optic neuritis
Optic neuritis may be caused by certain drugs, such as vincristine, used in the treatment of lymphoma. Imaging in such cases may be normal or show non-specific features. Temporal association between the treatment and onset of symptoms and exclusion of other causes can help in establishing the diagnosis.
The constellation of imaging features in this case along with leukocytosis and elevated blood sugar level led to the diagnosis of spread of infection from the paranasal sinuses to the left optic canal and orbit, causing optic neuritis and orbital cellulitis. The patient was given an urgent referral to an ear, nose, throat physician, and ophthalmologist and acute management was started.
Optic neuritis and orbital cellulitis caused by adjacent sinusitis.
DLBCL is an aggressive lymphoma that commonly presents with extranodal involvement, with the gastrointestinal tract being the most frequent site of extranodal disease. However, it can affect almost any organ, including the head-and-neck and CNS. Optic neuropathy in lymphoma can be due to a variety of causes, including lymphomatous infiltration, infections, inflammation, and drug- or radiation-induced neuropathy, all of which can have a similar clinical presentation. Lymphomatous infiltration of the optic nerve can occur as a part of CNS involvement (in around 5% of the cases) or as an isolated finding. Imaging features include thickening and enhancement of the affected optic nerve, with or without thickening of the associated soft tissue. In this case, the presence of adjacent sinusitis, features of inflammation, proximity of the optic canal to the sinuses, neutrophilic leukocytosis, and uncontrolled blood glucose level led us to the diagnosis of sinusitis resulting in optic neuritis and orbital cellulitis, rather than lymphomatous infiltration of the optic nerve.
In cases of hematolymphoid malignancies, it is important for oncologists to know not only the features of the disease process but also the features of the infective processes that can occur as a complication of the disease, so that they can be recognized and treated early. Sinusitis can lead to life-threatening complications through orbital and intracranial spread, out of which the former is encountered more frequently. Cross-sectional imaging plays an important role in the diagnosis of these complications. The anatomical relationship of the optic canal to the paranasal sinuses is assessed by the Sagar classification (modification of the Delano classification), which categorizes optic canals into five types:
- Type 1: The canal is superolateral to the sphenoid sinus, and there is no indentation of the sinus wall
- Type 2: There is indentation of the sphenoid sinus wall with <50% protrusion of the circumference of the nerve on coronal CT images
- Type 3: The optic nerve courses through the sphenoid sinus, with more than 50% of the circumference protruding into the sphenoid sinus
- Type 4: The canal is seen adjacent to the sphenoid and posterior ethmoidal cells or the presence of Onodi cells is observed
Type 4 optic canal was observed in our case. We have labeled the appearance of the optic canal traversing through the sinuses on axial images as, “The hyperloop sign” [Figures 3 and 4]
Optic neuritis is a rare complication of sinusitis, and it is important to consider the anatomical relationship of the sinuses to the optic canal in such cases. It also has important surgical implications, as the optic nerve can be inadvertently damaged during endoscopic sinus surgery. Optic neuritis due to sinusitis should be suspected in cases with a history or symptoms of sinusitis, progressive vision loss, and in older patients. The mechanism of spread can be direct extension, through osteomyelitis of the sphenoid/ethmoid bones, or compression by mucoceles. The medial wall of the orbit (the lamina papyracea) is thin and contains multiple traversing nerves and vessels and dehiscences, which can transmit infections from the ethmoid sinuses to the orbit. The frontal sinus can transmit infections to the anterior cranial fossa and orbit through bony dehiscence. Bacterial thrombophlebitis of valveless veins can allow the spread of infection to the cavernous sinus with resultant thrombosis. Osteomyelitis of the sinuses can spread directly to the intracranial structures.
Table 1 shows the various orbital and intracranial complications of sinusitis and their clinical and imaging features.
Sinusitis as a cause of optic neuropathy, although rare, must be kept in mind, and the anatomical relationship of the optic canal to the sinuses should be assessed in such cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
1. Shah HJ, Keraliya AR, Jagannathan JP, Tirumani SH, Lele VR, DiPiro PJ. Diffuse large B-cell lymphoma in the era of precision oncology: How imaging is helpful Korean J Radiol. 2017;18:54–70
2. Nair SC, Gogia A, Arora S, Kumar L, Sharma A, Biswas A, et al Clinicopathologic features and outcomes of diffuse large B-cell lymphoma with extranodal involvement: A retrospective analysis Cancer Res Stat Treat. 2022;5:67–74
3. Suresh Babu M C, Sreevalli A. Extranodal diffuse large B-cell lymphoma: Real-world experience from an Indian tertiary cancer center Cancer Res Stat Treat. 2022;5:119–21
4. Myers KA, Nikolic A, Romanchuk K, Weis E, Brundler MA, Lafay-Cousin L, et al Optic neuropathy in the context of leukemia or lymphoma: Diagnostic approach to a neuro-oncologic emergency Neurooncol Pract. 2017;4:60–6
5. Kim JL, Mendoza PR, Rashid A, Hayek B, Grossniklaus HE. Optic nerve lymphoma: Report of two cases and review of the literature Surv Ophthalmol. 2015;60:153–65
6. Dankbaar JW, van Bemmel AJ, Pameijer FA. Imaging findings of the orbital and intracranial complications of acute bacterial rhinosinusitis Insights Imaging. 2015;6:509–18
7. Itagi RM, Adiga CP, Kalenahalli K, Goolahally L, Gyanchandani M. Optic nerve canal relation to posterior paranasal sinuses in Indian ethnics: Review and objective classification J Clin Diagn Res. 2017;11:C01–3
8. Del Noce C, Marchi F, Sollini G, Iester M. Swollen optic disc and sinusitis Case Rep Ophthalmol. 2017;8:421–4
9. Rothstein J, Maisel RH, Berlinger NT, Wirtschafter JD. Relationship of optic neuritis to disease of the paranasal sinuses Laryngoscope. 1984;94:1501–8
10. Osborn MK, Steinberg JP. Subdural empyema and other suppurative complications of paranasal sinusitis Lancet Infect Dis. 2007;7:62–7