Sarcoidosis-associated acro-osteolysis

Abstract

Sarcoidosis is characterised by the formation of noncaseating granulomas classically affecting lungs, lymph nodes and skin. Osteoarticular involvement affects up to 15% of patients; however, acro-osteolysis, destruction involving distal phalanges of fingers and toes, associated with sarcoidosis, is extremely rare. A 44-year-old woman with a history of biopsy-proven sarcoidosis managed with prednisone and methotrexate presented with swelling and pain in the distal fingers of her right hand without skin manifestations. Radiographic imaging showed erosion of distal phalanges on second, third and fifth fingers and bone resorption in bilateral toes. A biopsy of the finger lesions showed noncaseating granulomas consistent with sarcoidosis. She was diagnosed with sarcoid acro-osteolysis and started on adalimumab with clinical and radiographic improvement. While most cases of osteoarticular sarcoidosis are asymptomatic and respond to standard immunosuppression, we present a case with progressive and refractory clinical course. This is the first reported case of sarcoid acro-osteolysis affecting the toes.

Keywords: biological agents; musculoskeletal and joint disorders; musculoskeletal syndromes; pathology; respiratory medicine.

Figure 1

(A) Swelling of distal fingertips of second, third and fifth digits with nail bed flattening before the initiation of adalimumab. (B) Distal fingertips of second and third digit 1 year after initiation of adalimumab (C) Right-hand X-ray before the initiation of adalimumab shows lace-like reticular osteolysis involving right second, third and fifth distal phalanges suggestive of acro-osteolysis. (D) Right-hand X-ray 1 year after adalimumab shows treated lesions of bony sarcoidosis, without interval progression. No new lesions are seen.

Figure 2

(A) Right and left foot X-ray before the initiation of adalimumab shows soft tissue swelling of the right second toe with acro-osteolysis in a reticular pattern of the right second distal phalanx. There is also soft tissue swelling and osteolysis of the left distal phalanx second toe. (B) Right and left foot X-ray 1 year after adalimumab shows treated lesions of bony sarcoidosis, without interval progression. No new lesions are seen.

Figure 3

Nuclear medicine bone scan before the initiation of adalimumab shows multifocal osseous involvement by sarcoidosis in the distal phalanx of the second and third digits in addition to the proximal phalanx of the fourth finger.