Giant multiple xanthomas in familial hypercholesterolaemia

A 56-year-old woman with dyslipidaemia presented to the emergency department with fever and infectious giant tumours on her upper and lower limbs (Panels A–C). Group A Streptococcus pyogenes was isolated from blood and wound cultures. A surgical specimen of infectious tumours of an Achilles tendon (thickness of 45 mm; Panel D) revealed foamy macrophages and a cholesterol cleft, and a diagnosis of xanthoma was made (Panel E). The diagnosis based on genetic testing was heterozygous familial hypercholesterolaemia: there was a gain of function mutation in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene. She had multiple progressive tumours at her limb joints and Achilles tendons, since she was 15 years of age. She underwent coronary artery bypass graft surgery at 46 years of age. Her mother died suddenly in her sixties. It is well known that various diseases, especially lipid disorders, cause xanthoma. The presence of xanthoma is one of diagnostic criteria of familial hypercholesterolaemia. Xanthoma appears in mechanical stress-exposed parts of the body in patients with familial hypercholesterolaemia. In this case, we ruled out a combination of cerebrotendinous xanthomatosis or phytosterolaemia. Although her serum low-density lipoprotein cholesterol level was less than 100 mg per decilitre under the condition of receiving statin therapy for at least the past 10 years, the number of the xanthomas increased and xanthomas had become gigantic. As the next strategy, we will try to use a PCSK9 inhibitor to prevent increases in the number of and size of xanthomas. Giant multiple xanthomas in the whole body (Panel A). Giant multiple xanthoma on the hand (Panel B). Infectious giant xanthoma of the Achilles tendon (Panel C). Achilles tendon X-ray (Panel D). Haematoxylin and eosin staining of xanthoma (Panel E).