CASE PRESENTATION

Case 1. A 34-year-old Filipino female presented with a three month history of multiple bilateral tender red nodules over the distal lower limbs [Fig 1]. She felt well with no constitutional symptoms, no prior history of preceding infection, tuberculosis exposure, or animal contact. She had migrated from the Philippines five years ago. She had no smoking, alcohol or intravenous drug use. Prior to this episode, she had no significant medical issues, and was not on any medications or herbal supplements. On examination, she had tender erythematous subcutaneous nodules on her lower limbs with angular purpura [Fig 1]. There were bilateral ankle effusions, and no other synovitis elsewhere. The abdomen was soft and non-tender. Urinalysis, full blood count, biochemistry and creatinine kinase levels were normal. Erythrocyte sedimentation rate (ESR) was 44 mm/hr (N < 20 mm/hr), and C-reactive protein (CRP) 10 mg/dL (N < 4 mg/dL). Antinuclear antibody, extractable nuclear antigen, cryoglobulin, cryofibrinogen, rheumatoid factor, anticardiolipin antibody, β-2 glycoprotein antibody, lupus anticoagulant, antineutrophil cytoplasmic antibodies, hepatitis B, hepatitis C, HIV, measles, mumps, and rubella were negative. The interferon gamma release assay was negative. Incisional biopsy demonstrated fibrinoid necrosis of an arteriole with a marked perivascular infiltrate composed of lymphocytes, neutrophils, histiocytes and eosinophils, extending to the subcutis. Histiocytes were inconspicuous and PUTT and ABPAS staining demonstrates no pathogens. [Fig 2]. Whole body PET-CT and CT abdominal angiogram showed no systemic vessel involvement, or end organ ischemia. Prednisone 40mg daily was commenced with normalisation of ESR, CRP, and complete resolution of subcutaneous nodules after two weeks. Prednisone was reduced and methotrexate commenced as a steroid-sparing agent.Case 2. A55-year old man was referred with a five month history of right lower limb ulcer associated with sensory changes in the lower limb. There were no constitutional symptoms or other symptoms to suggest systemic disease. Examination demonstrated a stellate ulcer with retiform purpura [Fig 3] and sensory deficit along the sural nerve. Physical examination was otherwise unremarkable. An incisional biopsy demonstrated a prominent lymphohistiocytic infiltrate of small to medium sized vessels in the deep dermis and subcutis. A moderate lymphohistiocytic infiltrate was noted within vessel walls with endarteritis obliterans, degenerate vessel walls and fibrin thrombi with karyorrhexis in affected lumens. His investigations showed normal urinalysis, blood count, urea, and electrolytes with no features of systemic involvement on imaging. Nerve conduction studies demonstrated isolated right common peroneal neuropathy with no evidence of a generalised neuropathy or mononeuritis multiplex. The patient was commenced on a tapering regime of prednisone 60mg daily, methotrexate 15mg weekly and colchicine 0.5 mg tds with resolution of the ulcer over a period of months. The sensory deficit remained fixed. Follow-up one year later showed no recurrence of symptoms or signs of vasculitis.