Extrarenal rhabdoid tumor presented with an immobile arm in a one-year-old boy
Chi-Ting Chung1, Yen-Lin Liu2, Chien-Jui Cheng3
1School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Medical Education, Taipei Medical University Hospital, Taipei, Taiwan.
Insights
An immobile arm in infants can mask aggressive extrarenal extracranial rhabdoid tumors (ERRT). Early diagnosis and treatment are crucial for managing this rare pediatric cancer involving the brachial plexus and spinal cord.
Area of Science:
- Pediatric Oncology
- Neuro-oncology
- Genetics
Background:
- Infants presenting with an immobile arm may initially be misdiagnosed in primary care.
- Differential diagnoses for pediatric brachial plexus issues include injuries, infections, neuropathies, and neoplasms.
Observation:
- A one-year-old boy with initial brachial plexus palsy diagnosis showed progressive neurological decline, including quadriparesis.
- MRI revealed a large supraclavicular fossa tumor invading the brachial plexus, thoracic cavity, and spinal canal.
Findings:
- Microscopic analysis showed malignant rhabdoid tumor cells with loss of INI1 expression.
- Genetic testing confirmed a deletion at 22q11.23 involving the SMARCB1 gene, leading to a diagnosis of cervical paravertebral malignant rhabdoid tumor with intraspinal invasion.
- The tumor responded well to chemotherapy (VDC/IE), with neurological recovery.
Implications:
- Extrarenal extracranial rhabdoid tumor (ERRT) is a rare, aggressive pediatric cancer.
- ERRT involving the spinal cord or peripheral nerves can present with subtle neurological symptoms.
- Neoplasms like ERRT should be considered in the differential diagnosis of infantile brachial plexus issues.
Abstract:
Infants with an immobile arm may be easily overlooked in primary care settings. Differential diagnoses include injuries, infections, neuropathies, ischemia and rarely, neoplasms. We report the case of a one-year-old boy with weakness in his left arm after minor trauma with a diagnosis of brachial plexus palsy initially. After rehabilitation for 2months, his weakness progressed to unsteady gait and quadriparesis. MRI revealed a huge solid tumor in the left supraclavicular fossa, which also involved the left brachial plexus, upper thoracic cavity, and left paravertebral space with invasion into the spinal canal. Microscopically, the medium-large polygonal tumor cells had an eccentric eosinophilic cytoplasm and immunostaining showed a loss of nuclear INI1 expression. Array comparative genomic hybridization of the tumor tissue confirmed a segmental deletion at chromosome region 22q11.23 involving the SMARCB1 gene. The final diagnosis was cervical paravertebral malignant rhabdoid tumor with intraspinal epidural and intradural invasion, a rare case of extrarenal extracranial rhabdoid tumor (ERRT). The intraspinal part of the tumor was resected followed by interval-compressed chemotherapy with vincristine-doxorubicin-cyclophosphamide alternating with ifosfamide-etoposide (VDC/IE). The tumor showed very good partial response to four cycles of chemotherapy with gradual recovery of neurological symptoms. ERRT is a very rare and aggressive tumor that mainly occurs in infants and children and may manifest with vague neurological symptoms when it involves the spinal cord and/or peripheral nerves. A neoplasm such as ERRT originating from or involving the brachial plexus should be considered in the differential diagnosis of an immobile arm in infancy.
