Rhombencephalitis and longitudinal extensive myelitis associated with dinutuximab use in high-risk neuroblastoma.

BACKGROUND: Dinutuximab is a monoclonal antibody that targets the GD2 antigen used in the treatment of high-risk neuroblastoma. Dinutuximab-associated rhombencephalitis and myelitis is a rare, steroid-responsive, serious, but reversible pathology. To date, three transverse myelitis cases and one rhombencephalitis case due to dinutuximab have already been reported. Moreover, a recently published article identified five inflammatory CNS demyelination cases (four myelitis and one rhombencephalitis). We present a 5-year-old patient with rhombencephalitis and myelitis following dinutuximab-beta treatment. CASE: A 5-year-old patient with a left-sided retroperitoneal mass infiltrating the left kidney and multiple lytic bone lesions was diagnosed with neuroblastoma with a percutaneous biopsy from the abdominal mass. Surgery was performed after a prominent treatment response was detected on the abdominal CT. Radiotherapy was applied to the abdomen. While she was still undergoing maintenance treatment with 13-cis retinoic acid, a metaiodobenzylguanidine (MIBG) scan detected new bone lesions, and brain MRG identified pachymeningeal involvement. A new chemotherapy regimen was started and decreased MIBG uptake was seen in all previous bone lesions. However, newly developed eighth rib metastasis was seen in the following MIBG scan. Autologous stem cell transplantation was done. Soon after, dinutuximab-beta, together with temozolomide and irinotecan, was initiated. Following the third cycle hypotension, somnolence, paraparesis, and unilateral fixed dilated pupil were developed. Afterward, hemiballismus-like irregular limb movements were observed. Work-up studies were unremarkable, except for hypodensity in the brain stem on the brain CT. MRI revealed T2 hyperintensity of the brainstem and spinal cord extending from the cervicomedullary junction to the T7 level. Moreover, incomplete contrast enhancement and facilitated diffusion were observed. Imaging findings suggested demyelination. Steroids and intravenous immune globulin (IVIG) treatment were initiated. Both imaging abnormalities and clinical symptoms resolved partially at one month and disappeared at six months. CONCLUSIONS: Awareness of the radiological findings of dinutuximab toxicity will lead to prompt diagnosis and treatment.

Early-onset juvenile dermatomyositis: A tertiary referral center experience and review of the literature.

BACKGROUND/OBJECTIVES: The aim of our study is twofold: To evaluate the presentation, diagnosis, clinical course, and management of juvenile dermatomyositis (JDM) in children under three years of age, and to compare with older-onset patients. METHODS: Nine patients with early-onset, and 63 patients with older-onset JDM followed between December 2010 and April 2022 are included. We also reviewed the literature on early-onset JDM from the inceptions of the PubMed/MEDLINE and Scopus databases up to April 1st, 2022. RESULTS: Early-onset JDM patients were characterized by longer median diagnostic delay (p = 0.005), calcinosis (p = 0.006), anti-NXP2 antibody (p = 0.049). Diagnostic pathway included muscle biopsy (77.7% versus 50.8%). Muscle biopsy findings were more severe in the early-onset group (p<0.001). Although there was no difference in the partial and complete remission rates, the relapse rate was significantly higher in the early-onset group (p = 0.001), reflected to requirement of intravenous immunoglobulin (p = 0.001), cyclophosphamide (p = 0.011), and biological agents (p = 0.016). Literature search revealed 32 articles reporting 75 patients. The median diagnostic delay was 5 (1-30) months. Calcinosis was present in 29.5%. Twenty-three of the 44 patients (52.3%) had a muscle biopsy. Forty-one patients (64.1%) received second and third-line treatments. Complete remission was achieved in almost half of these patients (48.9%), but relapse was observed in 75%. The mortality rate was 10.2%. CONCLUSION: Diagnosis can be challenging and delayed in early-onset JDM patients. Compared to older-onset JDM patients, this group had higher relapse rate, more severe muscle biopsy findings, and received intensive immunosuppressive treatment.

Ifosfamide-induced Encephalopathy With Rapid Response to Thiamine: A Pediatric Case.

Ifosfamide is an important chemotherapeutic agent used in the therapeutic protocols of many malignant tumors. Central nervous system toxicity of ifosfamide manifests with encephalopathy in 10% to 30% of patients treated with ifosfamide. Thiamine and methylene blue have been reported beneficial in the treatment and prevention of ifosfamide-induced encephalopathy (IIE). We describe an episode of encephalopathy developed at the third cycle of ifosfamide treatment in a child with Ewing sarcoma. With the administration of thiamin, the encephalopathy resolved and no episode was noted during subsequent courses of ifosfamide. Previous use of cisplatin, concomitant use of opioids, low levels of serum albumin and hemoglobin, and elevated levels of serum creatinine are potential risk factors for IIE. The current case illustrates the possibility of IIE even in the absence of such additional risk factors, treated successfully with thiamin and draws attention to the need for close neurological monitorization of patients treated with ifosfamide.

Thalassemia Major and Priapism: A Case Report of an Adolescent.

Priapism is defined as a prolonged pathologic penile erection without sexual stimulation. In children, priapism secondary to sickle cell disease or hematological malignancy is a frequent condition. Appropriate treatment of priapism varies; the treatment is primarily etiological, conservative management. In the present report, we aimed to present a case of asplenic thalassemia major who developed priapism, improved with hydration and ibuprofen treatment. Clinicians should take into account that priapism can be encountered in patients with thalassemia major. To our knowledge this is the second publication reporting the association between thalassemia major and priapism in childhood.