Yellow plaques as cutaneous markers of internal disorders

Kian Zarchi, Gregor BE Jemec

 Department of Dermatology, Roskilde Hospital, Health Sciences Faculty, University of Copenhagen, Denmark

Correspondence Address:
Kian Zarchi
Department of Dermatology, Roskilde Hospital, Koegevej 7-13, 4000 Roskilde
Denmark

A 79-year-old man with rheumatoid arthritis and chronic obstructive lung disease presented with a 5-year history of yellow plaques on his body and face. He denied pruritus, pain, or any other local symptoms. Physical examination revealed extensive, flat, well-demarked, yellow plaques, symmetrically distributed on the trunk, upper arms, and neck [Figure - 1]. Laboratory workup showed slightly elevated total cholesterol (240 mg/dl, 6.2 mmol/l), borderline high low-density lipoprotein cholesterol (155 mg/ dl, 4.0 mmol/l), and normal levels of triglycerides and high-density lipoprotein cholesterol (evaluation according to the American Heart Association guidelines). Full blood count, liver, thyroid, and renal function tests were within normal limits. A clinical and histopathological diagnosis of diffuse plane xanthoma was made. Further examinations were done, showing that abdominal and pelvic ultrasonography, chest x-ray, and urinary Bence-Jones protein were all within normal limits; however, the presence was detected of M-component in plasma, identified as IgG-kappa. The patient was referred to the regional Department of Hematology where further examinations, including bone marrow biopsy, led to the diagnosis of monoclonal gammopathy of undetermined significance (MGUS).

Figure 1: Flat, well-demarked, yellow plaques, symmetrically distributed on the trunk, upper arms and neck

Xanthomas are characterized by deposition of cholesterol-rich lipid in the skin and tendons. Clinically, they present as yellow papules, plaques, nodules, or tumors. Most clinical subtypes (tendinous, tuberous, eruptive, palmar, and xanthelasma palpebrarum,) are associated with familial hyperlipidemias. However, xanthomas may also occur in normolipidemic patients, and diffuse plane xanthoma has been described as being associated with hematologic disorders such as multiple myeloma, chronic lymphatic leukemia, chronic myeloid leukemia, and MGUS. In this case, although the patient did not present with any symptoms indicating the presence of a hematologic disorder, further investigations were carried out, eventually leading to the diagnosis of MGUS. Because of the morbidity and mortality, related to hyperlipidemia and hematologic malignancies, early recognition can be lifesaving; accordingly, every patient presenting with xanthoma should undergo a meticulous examination, including appropriate laboratory workups.