Seronegative rheumatoid nodulosis: a new case report

ARTICLE

ejd.2012.1696

Auteur(s) : Yue-Ping Zeng gvtao@yahoo.com.ch, Tao Qu

Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China

Rheumatoid nodulosis (RN), a benign variant of rheumatoid arthritis (RA), is characterized by multiple rheumatoid nodules, recurrent articular symptoms, minimal clinical or radiological involvement with frequent rheumatoid factor (RF) positivity [1, 2]. Here, we describe a new case of RN with negative RF.

A 49-year-old Chinese woman presented with a 1-year history of recurrent painful erythematous nodules over the extremities. The lesions initially appeared on her legs and ankles and gradually spread to the knees, elbows, and dorsa of her fingers. The lesions regressed spontaneously in approximately one month, and recurred repeatedly. Two weeks before her first presentation, she experienced episodic pain in the proximal interphalangeal joints, knees and ankles. She was otherwise healthy. There was no history of trauma, no significant past medical history and no family history of rheumatic diseases.

Physical examination revealed multiple erythematous firm nodules on the dorsal aspect of her left fourth finger (figure 1A), extensor surface of the left elbow and right knee, both legs and ankles (figure 1B). The subcutaneous nodules were slightly tender and immovable, ranging from 0.5 cm to 2 cm in diameter.

The routine laboratory tests were normal. Serological panel tests for RA, including RF, anti-perinuclear factor (APF) antibody, anti-keratin antibody (AKA), and anti-cyclic citrullinated peptide (CCP) antibody were all negative. Radiographs detected no evidence of calcification or arthritis. Skin nodule biopsies revealed characteristic features of rheumatoid nodules (figures 1C-D). A diagnosis of RN was established. The joint pain improved under treatment with leflunomide 20mg/d for 1 month, but the nodules persisted.RN was first described by Baywaters in 1949 and the diagnostic criteria were established in 1988 by Couret et al. [1]. Four criteria for RN are required:

• (1). multiple subcutaneous rheumatoid nodules, identified histologically,
• (2). palindromic rheumatism with minimal clinical or radiological involvement,
• (3). benign clinical course,
• (4). no or mild systemic manifestations of RA [1].

RN shares some clinical and histological features with a large variety of dermatological diseases [2]. Clinically, differential diagnosis includes subcutaneous granuloma annulare (SGA), gouty tophi, xanthomas, subcutaneous sarcoidosis, reticulohistiocytosis, etc [2, 3]. Histologically, the differential diagnosis mainly includes other necrobiotic granulomas such as SGA and necrobiosis lipoidica [2, 4]. Thus, the SGA is the principal differential diagnosis of RN owing to comparable clinical and histological findings [2, 4]. The distinguishing features between RN and SGA are summarized in table 1[2, 4].

Table 1 Comparative clinical and histological features between rheumatoid nodulosis and subcutaneous granuloma annulare

Neither RF positivity nor the presence of subchondral cysts of small bones is essential to the diagnosis of RN [1]. According to the review made by Couret et al. in 1988, only four of the 26 cases reported were RF negative [1]. In 2003, Maldonado et al. described a group of 16 patients diagnosed with RN who were followed up for a period of 1-12 years [3]. Interestingly, they found 11 of these patients with negative RF in the early course of the disease, but all 16 patents with positive RF in the later course of the disease. RN usually runs a more benign clinical course than classic RA and does not appear to develop erosive arthritis and systemic manifestations of classic RA [4, 5]. However, some cases with RN developed destructive polyarthritis after a long-term follow-up [3, 6]. Early positive RF was a probable indicator of progression to classic RA in patients with RN [3]. We will follow up our patient with interest to see if serum RF turns positive and to detect the possibility of progression to classic RA.

Dislosure

Financial support: none. Conflict of interest: none.

References

1. Couret M, Combe B, Chuong VT, et al. Rheumatoid nodulosis: report of two new cases and discussion of diagnostic criteria. J Rheumatol 1988; 15: 1427-30.

2. Garcia-Patos V. Rheumatoid nodule. Semin Cutan Med Surg 2007; 26: 100-7.

3. Maldonado I, Eid H, Rodriguez GR, et al. Rheumatoid nodulosis: is it a different subset of rheumatoid arthritis? J Clin Rheumatol 2003; 9: 296-305.

4. Hewitt D, Cole J. Rheumatoid nodules without arthritis. Australas J Dermatol 2005; 46: 93-6.

5. Toussirot E, Tiberghien P, Balblanc JC, et al. HLA DRB1* alleles in rheumatoid nodulosis: a comparative study with rheumatoid arthritis with and without nodules. Rheumatol Int 1998; 17: 233-6.

6. Roux F, Wattiaux MJ, Hayem G, et al. Rheumatoid nodulosis. Two cases with destructive polyarthritis after 20 years. Joint Bone Spine 2006; 73: 208-11.