Pheochromocytoma due to a novel SDHD variant presenting as unilateral visual loss

Abstract

Summary

A 53-year-old female presented to a tertiary ophthalmology referral centre complaining of unilateral painless loss of vision. Subsequent assessment revealed malignant hypertension causing right-sided cystoid macular oedema. During the course of secondary hypertension workup, she was diagnosed with a 7.8 cm phaeochromocytoma which was resected. Testing for a panel of all predisposing phaeochromocytoma-causing variants using next-generation sequencing resulted in the diagnosis of a novel SDHD variant.

Learning points

• Screening for secondary causes of hypertension is indicated when there is evidence of hypertension-mediated end-organ damage ( 1).

• Testing for a predisposing variant should be considered in all patients with phaeochromocytoma or paraganglioma due to the high heritability rate and prevalence of somatic variants ( 2, 3, 4).

• Novel variants are commonly uncovered in the Succinate Dehydrogenase (SDH) subunit; proving pathogenicity is a complex, time-consuming process and one challenge of next-generation sequencing ( 3).

• SDHB immunohistochemistry as a tool for demonstrating pathogenicity is associated with reduced sensitivity when assessing SDHD variants ( 5, 6).