Lichen amyloidosis associated with rheumatoid arthritis: unique presentation in a Bulgarian patient.

An 80-year-old Caucasian female patient presented with a two-year history of intensively itching skin rash located on her left lower leg and mild swelling of the proximal interphalangeal and metacarpophalangeal joints, accompanied by morning stiffness around these joints, lasting at least one hour before maximal improvement (Figures 1A and 1B). She reported having had a long-lasting medical history of accompanying diseases that had been controlled with medicines. These conditions included arterial hypertension, hypothyroidism, chronic pyelonephritis, angina pectoris and primary glaucoma. There was no family history of cutaneous disorders. Presence of intensively pruritic erythematous papules located on the left pretibial surface was established clinically (Figures 1A and 1B). Symmetrical soft-tissue swelling around the small joints was also observed, but no rheumatoid nodules were seen. The laboratory blood tests did not reveal any abnormalities in the complete or differentiated blood count. The kidneys and liver showed normal functioning. The rheumatoid factor was 827 u/ml (reference values: less than 40-60 u/ml). Presence of periarticular osteopenia in the interphalangeal and metacarpophalangeal joints was established radiographically. A diagnosis of seropositive rheumatoid arthritis was made, which met most of the criteria postulated by the committee of the American Rheumatism Association. Immunological testing for antinuclear antibody (ANA) and Scl 70 was negative. The cutaneous pathological changes presented required a wide spectrum of differential diagnoses, including pretibial myxedema, necrobiosis lipoidica, the small papular form of cutaneous sarcoidosis, T-cell lymphoma, lichen ruber planus and Arndt-Gottron scleromyxedema. Histopathological evaluations on skin biopsies revealed hyperkeratosis, focal acanthosis, subepithelial structures that stained pink with hematoxylin-eosin and mild to moderate mononuclear infiltrate around single vessels (Figure 2A). Subepithelial Congo red-positive deposits were also observed (Figures 2B and 2C), which showed blue-green birefringence under polarized light. The findings were characteristic of amyloid deposition and a diagnosis of lichen amyloidosis was made. No clinical or laboratory evidence of systemic amyloidosis was presented. Systemic therapy consisting of bilastine (20 mg daily) and acitretin (15 mg daily) was started, with topical application of 0.1% mometasone furoate cream, which produced a satisfactory therapeutic response. The patient was referred to a rheumatological unit for further therapy with biological agents. Localized cutaneous amyloidosis encompasses several conditions characterized by deposition of amyloid or amyloid-like proteins in the dermis, including macular amyloidosis and lichen amyloidosis.1 Nodular localized cutaneous amyloidosis is another condition in this group: it is the rarest type and distinct from the other two. In this type, plasma cells produce immunoglobulin light chains that are precursors to the amyloid fibril protein called amyloid L.1 Lichen amyloidosis is a primary form of localized cutaneous amyloidosis that is clinically manifested through hyperkeratotic erythematous to brownish papules, while amyloid deposition IMD, PhD. Professor, Department of Dermatology, Venereology and Dermatological Surgery, Medical Institute of the Ministry of the Interior (MVR-Sofia), Sofia, Bulgaria; Associate Professor, “Onkoderma” Polyclinic for Dermatology and Dermatological Surgery, Sofia, Bulgaria. IIMD. Surgeon, “Onkoderma” Polyclinic for Dermatology and Dermatological Surgery, Sofia, Bulgaria; Chair, Department of Dermatology and Venereology, School of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria. IIIMD, PhD. Director, Department of Dermatology and Allergology, Academic Teaching Hospital Dresden-Friedrichstadt, Friedrichstrasse, Dresden, Germany.