Sequential appearance of small vessel vasculitis and neutrophilic panniculitis in a patient with rheumatoid arthritis: further insight into the mechanism of this infrequent panniculitis

Neutrophilic Infiltrates in Panniculitis: Comprehensive Review and Diagnostic Algorithm Proposal

Neutrophilic infiltrates in panniculitis can be seen in different clinical-pathological entities. There are a "mostly neutrophilic inflammatory infiltrate" in some entities classically defined as neutrophilic panniculitis and already included in algorithms, such as enzymatic panniculitis, infective and factitial ones, erythema induratum, or subcutaneous Sweet syndrome, but there are also other panniculitis where neutrophils are frequently observed such as panniculitis associated with inflammatory bowel disease or rheumatoid arthritis, or drug-induced panniculitis associated with BRAF inhibitors, and finally, some panniculitis are better classified in other panniculitides groups but may present with neutrophil-rich variants, such as the neutrophil-rich subcutaneous fat necrosis of the newborn. We review the main clinical and histopathological features of most of these panniculitides and construct a diagnostic algorithm including these diseases.

Abatacept-Induced Panniculitis With Necrobiosis Lipoidica-Like Features in a Patient With Rheumatoid Arthritis

We present a 57-year-old female with a past medical history of rheumatoid arthritis, hypertension, and hypothyroidism who presented with poorly demarcated, nonblanching, painful, erythematous nodules on the bilateral lower legs for two weeks. The patient recently switched from infliximab to abatacept infusions, and skin eruptions presented 53 days from her initial abatacept infusion. A 5 mm punch biopsy of the left anterior upper leg in the zone of involvement showed a deep dermal granulomatous infiltrate with associated eosinophils and a vaguely horizontally palisaded pattern with necrobiosis. The granulomatous inflammation extended into the subcutaneous septae with a widening of the septae, edema, and lipomembranous fat necrosis. The patient was started on naproxen 500 mg PO BID and halobetasol propionate 0.05% lotion BID. Concomitantly, she was started on a four-day course of oral prednisone 10 mg PO daily and restarted infliximab infusions on the third day of prednisone treatment. At her initial infliximab infusions, she received one dose of solumedrol 40 mg and diphenhydramine 50 mg. The eruption resolved 21 days after the initial presentation. The present case is unique from the nine other cutaneous eruptions described after initiating abatacept therapy. Less than 10 cases of cutaneous panniculitides have been reported as adverse reactions to abatacept, with the most common reactions associated with oral contraceptives, nonsteroidal anti-inflammatory drugs, antibiotics, and leukotriene modifying agents. This case underscores the variety of histological findings in drug-induced panniculitis, highlighting the possibility of a drug reaction in a patient with rheumatological disease presenting with panniculitis.

Unusual, but important, peri- and extra-articular manifestations of rheumatoid arthritis: a pictorial essay

Ultrasonography is a useful technique to detect soft tissue changes of rheumatoid arthritisnot only synovitis, but also tenosynovitis, bursitis, and enthesitis-even at a subclinical stage. However, radiologists tend to focus on synovitis in daily practice, and unusual peri- or extra-articular manifestations of rheumatoid arthritis are difficult to detect at the initial presentation. This pictorial essay describes a broad spectrum of ultrasonographic findings in tendons, bursae, ligaments, subcutaneous tissues, bones, and nerves to assist in the accurate diagnosis of rheumatoid arthritis.