Paediatric relapsing polychondritis coexisting with Sjögren’s disease in a 10-year-old girl successfully treated with mycophenolate mofetil

Key message.

• Mycophenolate mofetil may be an effective treatment for paediatric relapsing polychondritis.

Dear Editor, Relapsing polychondritis (RP) is a rare, recurrent and progressive inflammation of cartilaginous structures, typically affecting the auricular, nasal and laryngotracheal cartilages. Paediatric cases of RP are notably infrequent, and the coexistence of other autoimmune diseases is rarely observed in children than in adults. We report a paediatric case of RP complicated by Sjögren disease (SjD).

At age 9, she experienced multiple episodes of auricular swelling that resolved spontaneously, which were retrospectively suggestive of the initial manifestations of RP. She also reported occasional headaches, joint pains in the knees or hips and mild chilblains; however, there was no family history of autoimmune disease.

Eight days before her admission, when she was 10 years old, the patient developed swelling of the parotid gland accompanied by fever, followed by swelling of the right auricle. On presentation, her temperature was 38.3°C, and physical examination revealed bilateral parotid and submandibular gland swelling, and erythema and oedema of the right auricle (Fig. 1A). Laboratory tests revealed normal blood counts (WBC: 4900/µL; neutrophils 64.4%; lymphocytes 31.3%), haemoglobin (13.6 g/dl) and platelets (298 000/µL). Inflammatory markers were mildly elevated (CRP 0.61 mg/dl and ESR 40 mm/h), and serum amylase was slightly elevated (221 IU/l). Immunological testing revealed elevated IgG (2087 mg/dl), low C3 titre (62 IU/ml) and positive rheumatoid factor (64.0 IU/ml). Additionally, a high antinuclear antibody titre (1:1280, speckled pattern) was identified, consistent with elevated anti-SS-A/Ro (70.6 IU/l), and markedly elevated anti-SS-B/La antibody (5100 IU/l). Computed tomography (CT) revealed thickening of the right auricle and nasal septum, as well as thickening of the thyroid and cricoid cartilages with blurring of the surrounding tissues, suggestive of inflammation extension (Fig. 1B). Minor salivary gland biopsy revealed marked periductal lymphocytic infiltration, with a focus score ≥1 focus per 4 mm² according to the Greenspan classification. Magnetic resonance sialography of the major salivary glands showed mild inflammatory changes, consistent with Stage I of the Rubin and Holt classification. Based on clinical and image findings, the patient was diagnosed with RP and coexisting SjD.

Figure 1.

Physical findings and imaging results. (A) Erythema and swelling of the right auricle with enlargement of the parotid region. (B) Contrast-enhanced CT showing thickening of the thyroid and cricoid cartilages with blurring of the surrounding adipose tissue (orange arrow). (C) Twelve months after discharge, auricular swelling had resolved. (D) Follow-up CT demonstrated complete resolution of the thickening in the thyroid and cricoid cartilage

Prednisolone (0.5 mg/kg) led to rapid resolution of fever and improved auricle and glandular swelling; it was discontinued after 1 week. Upon discharge, maintenance therapy with mycophenolate mofetil (MMF) 1500 mg (1200 mg/m²) was initiated. The patient remained symptom-free without auricular or airway recurrence for 2 years. A follow-up CT scan 12 months after discharge showed complete resolution (Fig. 1C and D).

RP primarily affects adults; consequently, reports of paediatric cases are rare. Paediatric-onset RP accounts for less than 5% of all cases, and its recurrent remissions and rarity may contribute to significant delays in recognition. In a series of paediatric RP cases, laryngeal involvement was present in 10% of patients at onset and occurred in 50% at some point during the disease course [1, 2]. In our case, despite the absence of respiratory symptoms, CT imaging showed thickening of the thyroid and cricoid cartilage. CT findings in RP often reveal thickening and calcification of the laryngeal cartilage and bronchial walls. Moreover, expiratory CT scanning allows the assessment of dynamic airway collapse and air trapping, supporting early diagnosis. Although MRI offers superior sensitivity in differentiating fibrosis from inflammation, its relatively lower spatial resolution limits the assessment of airway wall pathology—whereas CT remains the modality of choice for delineating detailed airway structural changes in RP [3].

Our case highlights the coexistence of RP and SjD, a comorbidity that may provide insight into shared immunopathological mechanisms. Previous reports have shown that one-third of adult-onset and 15% of paediatric-onset RP cases present with concomitant autoimmune diseases. Among these, SjD has been reported as the most associated autoimmune condition in adults [1, 4, 5]. In adults, VEXAS syndrome—an autoinflammatory disease characterized by RP accompanied by myelodysplastic syndrome or other hematologic abnormalities—has been reported. In paediatric populations, monogenic autoinflammatory diseases, including neonatal-onset multisystem inflammatory disease and protein kinase Cδ deficiency, have also been implicated in cartilage destruction [2, 6].

Currently, no standardized treatment has been established for RP. Intensive immunosuppressive therapy is warranted when life-threatening airway chondritis is present. In adult-onset RP, TNF inhibitors, interleukin-6 inhibitors and methotrexate have been proposed as effective treatments based on literature reviews and multiple case reports [7]. MMF and azathioprine are also considered effective options [8]. In the present case, MMF was selected due to its favourable tolerability and low incidence of severe adverse effects. Further research is needed to clarify the long-term prognosis of RP under MMF therapy, particularly in patients with coexisting autoimmune conditions.

This case underscores the necessity of evaluating tracheal cartilage involvement by CT in paediatric patients presenting with auricular chondritis, even in the absence of respiratory symptoms. Although the coexistence of SjD in paediatric RP is uncommon, clinicians should remain vigilant. The sustained remission observed following MMF therapy supports its potential as a treatment option in paediatric RP.

Data availability

The data pertaining to this case report are available from the corresponding author on reasonable request.

Funding

No specific funding was received from any bodies in the public, commercial or not-for-profit sectors to carry out the work described in this article.

Disclosure statement: The authors have declared no conflicts of interest.

Patient consent statement: Informed consent was provided for the publication of this case report.