Abstract Number: 42

Unusual presentation of subcutaneous granuloma annulare in an adult

C. Chew1, A. Mar1

Meeting: 2019 Dermcoll

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Subcutaneous granuloma annulare (SGA) is a rare variant of granuloma annulare most commonly affecting children. We report a 33-year-old female with a 2-year history of multiple plaques and subcutaneous nodules affecting her hands, elbow, ear and feet. Some lesions resembled rheumatoid nodules; the lesion on her left hand caused a trigger finger; and the nodule of the foot mimicked a Morton’s neuroma. Laboratory investigations were unremarkable for rheumatoid arthritis. Histological findings showed dermal necrobiosis with palisades of histiocytes and lymphocytic inflammation. Assessment with ultrasound of the foot nodule supported a diagnosis of subcutaneous SGA, with a non-compressible lesion located between the nerves rather than arising from the nerve. The patient was initially treated with hydroxychloroquine, low-dose methotrexate and a short course of prednisolone. She was unable to tolerate methotrexate and had an inadequate response to hydroxychloroquine. Some nodules responded to intralesional triamcinolone injections while others spontaneously resolved. SGA can mimic a rheumatoid nodule and Morton’s neuroma and be the cause of a trigger finger.