P032 Scleromyxoedema with associated IgG lambda paraproteinaemia: a challenging case of refractory cutaneous sclerosis

Abstract

Scleromyxoedema is a rare primary cutaneous mucinosis characterized by a papular sclerodermoid eruption and is frequently associated with monoclonal gammopathy. We present an interesting case of extensive scleromyxoedema with associated IgG lambda paraproteinaemia. A 40-year-old female patient with no significant past medical history was referred with a 10-month history of an itchy papular rash affecting the face and body. This initially started on the face before spreading to the limbs and trunk. Symptoms of pruritus were especially distressing to the patient. Other associated symptoms included polyarthralgia, muscle weakness, dizziness and headache. On examination there were widespread skin-coloured, flat-topped papules involving the face, neck, trunk and limbs. These coalesced to form firm plaques. Exaggerated skinfolds were evident on the neck (Shar-pei sign). Leonine facies were identified. Skin biopsies from the face demonstrated a dense dermal histiocytic infiltrate with increased mucin deposition on immunohistochemistry. Thyroid function tests were normal. Further investigation identified an IgG lambda paraprotein, and bone marrow biopsy revealed 7% plasma cells, confirming the diagnosis of scleromyxoedema associated with monoclonal gammopathy. The patient was treated with IVIg alongside antihistamines, resulting in improvement of the papular eruption and pruritus. However, marked skin thickening persisted despite intralesional corticosteroid therapy, leading to significant distress for the patient. This case highlights the characteristic clinical and histopathological features of scleromyxoedema, its association with IgG lambda paraproteinaemia, and the ongoing therapeutic challenges posed by refractory skin sclerosis in this rare condition.