Thymic carcinoma presenting with overlap polyarthritis and myositis: A rare paraneoplastic syndrome in childhood

Thymic tumors are very rare neoplasms in children and account for less than 1% of mediastinal tumors in pediatric patients. One-third of the pediatric patients present with symptoms related to the compression of the tumor mass on the surrounding anatomic structures, and paraneoplastic syndromes such as myasthenia gravis, pure red cell aplasia, acquired hypogammaglobulinemia, and connective tissue disorders, which rarely occur in children with thymic tumors. Herein, we report a case of thymic carcinoma mimicking the symptoms of a connective tissue disease with symmetrical polyarthritis accompanying myositis, fever, weight loss, and malaise in a 15-year-old male patient. To our knowledge, this is the first case pediatric thymic carcinoma accompany with severe polyarthritis and myopathy, thus we have reviewed the current literature regarding the cases of thymic malignancies coexisting with paraneoplastic syndromes in children.

How Safe Are Biological Agents in Pediatric Rheumatology?

OBJECTIVE

Biologic therapy has changed the prognosis of patients with rheumatologic disease. Despite all benefits of the biological agents, adverse events may occur due to their long-term use. The aim of this study is to analyze the adverse events observed in pediatric patients who received biological treatment.

MATERIALS AND METHODS

This retrospective observational cohort study was conducted between January 2010 and January 2022. File records of 139 patients used biological agents for rheumatologic diseases in a pediatric rheumatology clinic were evaluated. Diagnosis, received treatment, the rationale for stopping treatment, requirement of tuberculosis prophylaxis, presence of an adverse event, and results were recorded.

RESULTS

The most used biological therapy was etanercept (41.7%). Anakinra, adalimumab, canakinumab were used in 30.9%, 27.3%, 23.7% of patients, and the others in less than 10%. Totally 491 adverse events (97.9/100 patient-years) were encountered during the duration of biological treatment. The most often adverse event was recurrent upper respiratory tract infection in the patients (31.9/100 patient-years). Elevated aminotransferase levels (10.4/100 patient-years), abdominal pain (7/100 patient-years), and headache (5.2/100 patient-years) were among the other common side effects. Isoniazid (INH) prophylaxis was needed before biological treatment in 20.9% of the patients. Tuberculosis developed in none of the patients followed-up for latent tuberculosis, however, it developed in a patient while receiving etanercept due to noncompliance with his scheduled outpatient visits during etanercept treatment.

CONCLUSION

The most commonly used biological treatments were TNFi and IL-antagonists, and the majority of side effects were infections and laboratory abnormalities. Although the rate of serious adverse events is quite low, close follow-up of patients receiving biological therapy is very important.

Adhesive small-bowel obstruction as a challenging complication of familial Mediterranean fever: A case-based review

Familial Mediterranean fever (FMF) is the most common inherited autoinflammatory disorder, characterized by recurrent and self-limiting episodes of fever and serosal inflammation. Recurrent serositis may rarely lead to the formation of adhesions in the peritoneum, which may result in mechanical bowel obstruction. The symptoms, such as abdominal pain and vomiting, may mimic typical FMF attacks, resulting in misdiagnosis and severe morbidity, including strangulation and intestinal necrosis. Physicians are generally aware of other complications associated with FMF but reports on peritoneal adhesions and intestinal obstruction in English-language literature are inadequate to increase clinicians' awareness. Therefore, it is crucial to meticulously evaluate FMF patients presenting with abdominal pain and ileus because these symptoms could be due to adhesive small-bowel obstruction (ASBO). Furthermore, patients presenting with ASBO without a history of abdominal surgery should also be thoroughly evaluated, especially as it could be an initial presentation for an autoinflammatory disease. Herein, we present a pediatric case of FMF with the M694V homozygous mutation, complicated by ASBO while under colchicine treatment. Additionally, we provide a comprehensive review of the available literature on ASBO in FMF.

A possibly new autoinflammatory disease due to compound heterozygous phosphomevalonate kinase gene mutation

BACKGROUND

Mevalonate kinase (MVK) plays a role in cholesterol and non-sterol isoprenoid biosynthesis and its deficiency-related diseases are caused by bi-allelic pathogenic mutations in the MVK gene, (MVK), which leads to rare hereditary autoinflammatory diseases. The disease may manifest different clinical phenotypes depending on the degree of the deficiency in the enzyme activity. The complete deficiency of the enzyme activity results in the severe metabolic disease called mevalonic aciduria, while a partial deficiency results in a broad spectrum of clinical presentations called hyper-immunoglobulin D syndrome (HIDS). Serum immunoglobulin (Ig) D and urine mevalonic acid levels may be increased during inflammatory attacks of HIDS.

CASE PRESENTATION

Herein, for the first time in the literature, we present a 6-year-old male patient who suffered from recurrent episodes of fever, polyarthritis, skin rash, diarrhea, abdominal pain, and inflammatory bowel disease-like manifestations with elevated levels of serum IgD, and urine mevalonic acid. Eventually we detected compound heterozygous mutations in the phosphomevalonate kinase (PMVK) gene coding the second enzyme after mevalonate kinase in the mevalonate pathway.

CONCLUSION

For patients presenting with HIDS-like findings, disease exacerbations and persistent chronic inflammation, and having high urinary mevalonic acid and serum IgD levels, raising suspicion in terms of MVK deficiency (MVKD), it is recommended to study all mevalonate pathway enzymes, even if there is no mutation in the MVK gene. It should be kept in mind that novel mutations might be seen such as PMVK gene.