1/4. Epstein-Barr virus related opsoclonus-myoclonus-ataxia does not rule out the presence of occult neuroblastic tumors. Opsoclonus-myoclonus-ataxia (OMA) secondary to Epstein-Barr virus (EBV) infection has only been described in three pediatric patients. Previous reports suggested that evidence for a recent EBV infection in the absence of an occult neoplasm would predict a favorable prognosis for OMA as well as no tumor development. We present the case of a 20-month-old child with OMA associated with a microbiologically documented acute EBV infection and an occult thoracic ganglioneuroblastoma diagnosed 5 months later. ( info) |
2/4. Neuroblastoma found in a 4-year-old after rituximab therapy for opsoclonus-myoclonus. Opsoclonus-myoclonus, a rare paraneoplastic syndrome that may occur in patients with neuroblastoma, is thought to be a humorally mediated immune reaction to malignant cells that cross-react with autoantigens. This report describes the case of an occult neuroblastoma diagnosed in a 4-year-old female 2 years after presentation of opsoclonus-myoclonus. Although no mass was evident on previous imaging at an interval of 10 months, a computed tomographic scan 4 months after rituximab treatment and 20 months after presentation revealed a new left adrenal mass. Although neuroblastomas can be identified months after presentation of opsoclonus-myoclonus without treatment with rituximab, this report describes one of the longest intervals using up-to-date imaging techniques. Therefore the case raises two concerns: (1) whether the same immune process that causes opsoclonus-myoclonus may suppress neuroblastomas, and (2) whether immunosuppressive therapy with rituximab may inhibit the immune reaction to occult neuroblastomas in patients with unexplained opsoclonus-myoclonus. ( info) |
| We describe the case of a 2-year-old girl with opsoclonus-myoclonus syndrome treated with chronic adrenocorticotropic hormone (ACTH) in which a metaiodobenzylguanidine scan showed abnormal radiotracer uptake in the left adrenal gland region, interpreted as the site of an occult neuroblastoma. As this finding was not corroborated by previous or subsequent metaiodobenzylguanidine scans or by computed tomography (CT) or magnetic resonance imaging (MRI), we attribute the finding to being a false-positive result from adrenal hyperplasia owing to chronic use of ACTH and not to neuroblastoma. Metaiodobenzylguanidine scintigraphy is an extremely important nuclear medicine examination tool used for the evaluation and staging of pediatric neuroblastoma. We highlight the need for cautious interpretation of metaiodobenzylguanidine as a screening tool for neuroblastoma in patients treated with ACTH. ( info) |
| opsoclonus-myoclonus syndrome (OMS), a movement disorder characterised by chaotic eye movements and myoclonus, is a rare clinical entity. We present two cases of opsoclonus-myoclonus syndrome of paraneoplastic origin. In the first patient the syndrome was associated with a breast carcinoma and in the second patient with a non small cell lung carcinoma. However none of the commonly associated antibodies were found in these cases. From the neuropathological findings from the first patient we find arguments that support the current hypothesis on the pathophysiology of OMS namely a dysfunction in brainstem and cerebellum. We conclude that in adults with OMS one has to be very suspicious of a possible neoplastic origin of the syndrome. The antibodies associated with some cases of OMS are thought to play a role in the pathophysiology of the syndrome although the exact immunologic mechanism remains unknown. research into the neuropathological substrate of OMS yields a broad range of abnormalities in brain stem and cerebellum. However none of these findings seem to be pathognomonic. As for the possible therapy of OMS, several immunomodulating strategies can be used with varying success. At present there is no established standard therapy. ( info) |