Yellow subconjunctival deposits

Abstract

In this case report, we present a healthy man who was referred for removal of subconjunctival yellow lesions found during a routine eye examination. In histopathological examination, an amyloidosis was found. There were no remnants or new lesions during 1-year follow-up. There was no systemic involvement. Conjunctival amyloidosis is a rare diagnosis that often is overlooked. Failure to recognise conjunctival amyloidosis might lead to late diagnosis of systemic amyloidosis. This case may rise the awareness to this rare diagnosis.

Background

Amyloidosis is a systemic condition caused by deposition of insoluble abnormal amyloid fibrils intracellularly or extracellularly.¹ It was first described in 1854 by Rudolph Virchow.² Since then 36 different amyloid fibrillary proteins are known. The name of the subtype of the amyloidosis is based on the protein that accumulates. Symptoms depend on the subtype and are often variable.³ Light-chain (AL) amyloidosis is the most common form of systemic amyloidosis. It is a plasma cell disorder, where immunoglobulin light-chain fragments are deposited in tissues.³

Diagnosis of amyloidosis requires tissue biopsy.⁴ The most common stain in the diagnosis of amyloid is Congo red, which, combined with polarised light, makes the amyloid proteins appear apple-green on microscopy. Other stains include thioflavin T stain, immunohistochemistry, etc. It is also important to diagnose the subtype of amyloidosis because treatment depends on the type of amyloidosis that is present. The diagnosis of the subtype is done usually by electrophoresis. Systemic amyloidosis also can be diagnosed by detection of abnormal proteins in the bloodstream.^{5 6}

Ocular amyloidosis has been described in the past yet it is considered uncommon pathology.⁷ The ocular manifestations of the amyloidosis can be variable and can involve any ocular organs: lacrimal gland, eyelid, extraocular muscles, conjunctiva, cornea, vitreous, macula, and retina. Due to the rarity of the disease presentations, the clinical diagnosis is often overlooked,^{8 9} and the differential diagnosis include sarcoidosis, lymphoma, tuberculosis and inflammation.

We present a case that was referred to our consultation as suspected conjunctival lymphoma and was biopsy proven to be conjunctival amyldosis.

Case presentation

A 54-year old, healthy man was found to have, on a routine eye examination, a new, multiple subconjunctival yellow deposits in his left medial conjunctiva (figure 1). Conjunctival lymphoma was suspected and he was referred to our ocular oncology service for evaluation. He underwent excisional biopsy of the lesions which were sent for pathological examination.

Figure 1.

Clinical presentation: subconjunctival yellow deposits.

Histopathological examination of haematoxylin and eosin-stained sections demonstrated acellular, amorphous, eosinophilic material consistent with amyloid in the conjunctival stroma (figure 2A-B). Under polarisation, it displayed apple-green birefringence and dichroism, (figure 2C) and the pathological diagnosis was amyloidosis. Biochemical examination found AL-lambda-type amyloidosis. Serum-free light-chain monomer–dimer analysis showed no evidence of systemic AL amyloidosis. Urine tests exclude the presence of monoclonal protein related to monoclonal gammopathy of undetermined significance, which may convert to AL amyloidosis later.

Figure 2.

Histological evaluation. (A and B) Histopathological examination of haematoxylin and eosin-stained sections demonstrated acellular, amorphous, eosinophilic material consistent with amyloid in the conjunctival stroma. (C) Under polarisation, it displayed apple-green birefringence and dichroism.

In clinical and imaging evaluation, no cardiac or renal involvement was found.

One year after diagnosis, the patient had no new ocular or systemic complaints. No remnants or new lesions were found. No treatment was required.

Differential diagnosis

• Conjunctival lymphoma

• Amyloidosis

Treatment

Excisional biopsy

Outcome and follow-up

The patient had no new ocular or systemic complaints. No remnants or new lesions were found. No treatment was required.

Discussion

Conjunctival amyloidosis is an uncommon condition.¹⁰ In a review of 2455 conjunctival lesions submitted to a pathology laboratory, only five patients (0.002%) were found to have conjunctival amyloidosis.¹¹ Moreover, patients with amyloidosis may present with ocular symptoms that simulate conjunctival malignancies or inflammation. Because of those two main facts, the clinical diagnosis of conjunctival amyloidosis is often overlooked.¹⁰ Failure to suspect conjunctival amyloidosis might lead to unnecessary extensive surgical procedures that might be complicated with side effects.

In this case report, the initial referral diagnosis was conjunctival lymphoma which requires more aggressive treatment. The pathology changed the diagnosis. This is an example of the importance of pathological evaluation of such lesions. Conjunctival amyloidosis usually is a localised process that rarely is associated with systemic involvement. Of 50 well-documented patients of conjunctival amyloidosis reported in the literature, 44 (88%) were reported to be localised, non-systemic conjunctival amyloidosis, three (6%) were secondary conjunctival amyloidosis and three (6%) were associated with systemic amyloidosis.¹² Although rare, systemic amyloidosis may be present and very rarely may be a life-threatening conditions. Therefore, systemic evaluation is required for all patients.

In this case, a systemic evaluation including blood and urine test along with heart and kidney examination and no systemic involvement was found.

In summary, we present a case report of a middle-aged man with new asymptomatic yellow subconjunctival lesions that were found during a routine eye examination. The initial suspected diagnosis was conjunctival lymphoma but the final diagnosis was primary conjunctival amyloidosis. Conjunctival amyloidosis is a rare diagnosis that requires systemic evolution for the disease that can be life-threatening. This case report should raise the awareness to this rare diagnosis.

Learning points.

• Conjunctival amyloidosis is a rare diagnosis that requires systemic evolution.

• Systemic amyloidosis can be life-threatening disease.

• Failure to suspect conjunctival amyloidosis might lead to unnecessary extensive surgical procedures that might be complicated with side effects.