Sir,

Necrobiotic xanthogranuloma is a rare skin disease that may herald eye complications. We report the presentation of posterior scleritis in a patient 2 years after a skin biopsy-proven diagnosis of necrobiotic xanthogranuloma.

Case report

A 47-year-old Caucasian lady presented with a 3-day history of reduced vision in her right eye, redness, watering, photophobia, pain, and headache. She was already under regular follow-up for blepharitis. She had necrobiotic xanthogranuloma skin lesions proven by biopsy on her upper and lower limbs (Figure 1). She also had raised ESR, IgG-κ paraproteinaemia, neutropenia, lymphopenia, and low complement C4.

Figure 1
figure 1

Necrobiotic xanthogranuloma on the skin of the right thigh.

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Visual acuities were 6/18 right eye and 6/5 left eye. She had bilateral anterior blepharitis and anterior segments were otherwise unremarkable. Fundoscopy revealed bilateral choroidal folds and right cystoid macular oedema.

Ultrasonography showed irregular thickening of the sclera in both eyes (Figure 2). Magnetic resonance imaging of the orbits showed bilateral diffuse-enhanced thickening of posterior sclera but no orbital abnormality. A diagnosis of bilateral posterior scleritis associated with necrobiotic xanthogranuloma was made. She was commenced on prednisolone 60 mg daily. Her vision, symptoms, and signs improved dramatically and after 1 month, she was asymptomatic. Vision in both eyes was 6/5 2 months after starting treatment. Repeat ultrasonography showed complete resolution of the scleral thickening. Her skin lesions regressed and the paraproteinaemia also resolved. Prednisolone was tapered and finally discontinued after 4 months. She has remained asymptomatic for the past 3 years.

Figure 2
figure 2

B-scan ultrasonography of the eye before treatment. Note the irregular lumpy thickening of the globe.

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Comment

Necrobiotic xanthogranuloma is a rare progressive disease usually affecting patients in their fifth to seventh decades. It is characterised by red or yellow skin papules or indurated plaques with surface telangiectasia, which subsequently ulcerate and scar. Ophthalmological complications affect 50% of patients and include orbital and subconjunctival masses, keratitis, episcleritis, scleritis, and uveitis. Other organs may rarely be involved. Approximately 80% of patients have a monoclonal gammopathy and 10% of these patients develop multiple myeloma. Hepatosplenomegaly, high ESR, leucopenia, hypocomplementemia, and cryoglobulinaemia are other common findings.1 Necrobiotic xanthogranulomas are composed of histiocytes and Touton giant cells, forming palisades around zones of necrotic tissue, degenerated collagen, and cholesterol clefts. They are triggered by deposition of immunoglobulins and lipid complexes in affected tissues.2

Improvement of skin lesions has been seen with systemic corticosteroids, chlorambucil, melphalan, radiotherapy, interferon α-2a, and plasmapharesis. Intralesional injection of triamcinolone may be beneficial for accessible lesions.3, 4, 5 The scleritis in our patient was thought to be related to necrobiotic xanthogranuloma. Scleral biopsy was not carried out because we felt that it would have been technically difficult, potentially hazardous, and unlikely to add useful information. Her systemic diagnosis confirmed by skin biopsy and the beneficial response to steroid treatment supports our diagnosis.

Patients with necrobiotic xanthogranuloma may present to many specialties. Posterior scleritis is an uncommon but treatable sight-threatening complication of this disease. Prompt ophthalmological referral is warranted if eye symptoms develop.