Atypical teratoid rhabdoid brain tumor in an infant with ring chromosome 22.
Bottom Line: We present a case of a 4-month-old boy with 46,XY,r(22)(p13q13.3), generalized hypotonia and delayed development.High-resolution microarray analysis revealed a 3.5-Mb deletion at 22q13.31q13.33.At 11 months, the patient had an ATRT (5.6 cm×5.0 cm×7.6 cm) in the cerebellar vermis, which was detected in the brain via magnetic resonance imaging.
Affiliation: Green Cross Genome, Seoul, Korea.
Reports of constitutional ring chromosome 22, r(22) are rare. Individuals with r(22) present similar features as those with the 22q13 deletion syndrome. The instability in the ring chromosome contributes to the development of variable phenotypes. Central nervous system (CNS) atypical teratoid rhabdoid tumors (ATRTs) are rare, highly malignant tumors, primarily occurring in young children below 3 years of age. The majority of ATRT cases display genetic alterations of SMARCB1 (INI1/hSNF5), a tumor suppressor gene located on 22q11.2. The coexistence of a CNS ATRT in a child with a r(22) is rare. We present a case of a 4-month-old boy with 46,XY,r(22)(p13q13.3), generalized hypotonia and delayed development. High-resolution microarray analysis revealed a 3.5-Mb deletion at 22q13.31q13.33. At 11 months, the patient had an ATRT (5.6 cm×5.0 cm×7.6 cm) in the cerebellar vermis, which was detected in the brain via magnetic resonance imaging.
No MeSH data available.
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Mentions: A 4-month-old boy was referred to Department of Pediatrics, Daegu Catholic University of Medicine Center because of delayed development. He was the first child of healthy, unrelated Korean parents without any known disorders in their family histories. The mother was 22 years old and the father was 27 years old at the patient's birth. The pregnancy was uneventful with no evidence of teratogenic agent exposure. The patient was born at 37 weeks of gestational age by uncomplicated spontaneous vaginal delivery, and he weighed 2,500 g. The physical examination revealed unremarkable findings, except generalized hypotonia with decreased deep tendon reflexes of both knee joint was found. Primitive reflexes could not be elicited. He could not maintain his head well a majority of the time. The patient weighed 7.4 kg (50th percentile), and was 65 cm tall (50th percentile). Results of the brain and abdominal ultrasound and the echocardiography revealed nonspecific findings. Cytogenetic analysis on peripheral blood lymphocytes revealed an r(22) in all analyzed cells, specifically 46,XY,r(22)(p13q13.3) (Fig. 1). To specify the breakpoint, high-resolution microarray analysis was performed. Upon analyses of the genomic DNA using an Affymetrix Cytoscan 750K array analysis (Santa Clara, CA, USA), a 3.5-Mb deletion at 22q13.31q13.33 was revealed (Fig. 2). However, the SMARCB1 (INI1/hSNF5) gene at 22q11.2, which lies proximal to the break point, was not deleted. Both parents had normal karyotypes. Thus, this chromosomal alteration of the proband was possibly de novo. At 11 months of age, the patient was brought to the Emergency Department with altered consciousness after falling out of his bed at home. Results of brain MRI revealed a 5.6-cm×5.0-cm×7.6-cm mass in the cerebellar vermis (Fig. 3). Results of the abdominal MRI revealed nonspecific findings. The operation was performed via transvermian approach by midline suboccipital craniotomy. The mass, extending the 4th ventricle and the quadrigeminal cistern, was resected. However, it's unfortunate that we obtained small biopsy specimens. On histopathologic examination, most tumor was exclusively composed of small cell component (Fig. 4A). The tumor cells, which had some cytoplasm and vesicular nuclei, were larger than cells of medulloblastoma. The typical rhabdoid tumor cells with eosinophilic cytoplasm were not appeared, and there were no organoid arrangements such as rosette or palisading pattern in the obtained tumor tissue. Immunohistochemical staining for expression of the INI1 protein, showed loss of nuclear expression in the tumor cells (Fig. 4B). After operation, the patient's condition deteriorated with status epilepticus. A ventriculoperitoneal shunt for hydrocephalus underwent in the referred hospital. The chemotherapy (vincristine, cisplatin, doxorubicin, and cyclophosphamide) has been done until now.
No MeSH data available.