We report a 34 year-old woman with psoriasis, systemic lupus erythematosus (SLE), and recent anti-TNFa therapy, who presented with multiple, eruptive dermatofibromas (MEDF). Although the pathogenesis of MEDF remains unknown, there is substantial evidence that this phenomenon represents an aberrant immune response. Like the more common presentation of solitary dermatofibromas, these lesions are benign, and no treatment is required. However, MEDF is increasingly recognized as a sign of immune dysregulation and an appropriate work-up should be initiated to identify an underlying cause in patients without a known trigger.
Case synopsis HISTORY:A 32-year-old woman was referred to the Dermatology Clinic at Bellevue Hospital Center for the management of psoriasis. She had previously been treated with several systemic medications, which included methotrexate, adalimumab, and etanercept, without success. Most recently, she had been treated with ustekinumab for four months, which was discontinued in the setting of a severe, allergic reaction. Owing to the failure of multiple medications, her dermatologist recommended that she come to our clinic for further management. Apart from mild scale and pruritus of the scalp, she denied any active, psoriatic lesions. However, she did note a six-month history of eruptive, slightly-tender, hyperpigmented papules on her left lower leg and the dorsal aspect of the left foot. The lesions had appeared abruptly within four to five months of one another.Past medical history included systemic lupus erythematosus for which she was treated with prednisone 5mg daily and was followed by the Rheumatology Service. She denied any systemic symptoms, which included weight loss, fevers, chills, fatigue, joint pain, and gastrointestinal symptoms. A shave biopsy was obtained from a lesion on the dorsal aspect of the left foot.Physical examination: Six, small, approximately 5-mm, hyperpigmented, papules were scattered on the left lower leg and the dorsal aspect of the foot.
Laboratory data:A complete blood count showed a hemoglobin of 11.5g/mL but was otherwise normal. A metabolic panel was normal.Histopathology: There is a relatively well-circumscribed dermal lesion that is composed of intersecting fascicles of plump fibroblasts, with thick collagen bundles at its periphery. The overlying epidermis is hyperplastic.