Skull metastasis of neuroblastoma
Axial contrast-enhanced CT image shows enhancing bilateral dural metastases.

Case report

5-YO-male patient was admitted to the hospital with headache. Contrast-enhanced CT (ceCT) of the spine revealed  scalp soft-tissue mass in parietal region (blue arrows), periosteal response to tumor cells extending from calvarial metastases (green arrow), bilateral dural metastases (red arrows). CT of the abdomen show left adrenal mass. On pathology – neuroblastoma.

Axial ceCT image shows bilateral dural metastases.
Axial ceCT image shows bilateral dural metastases.
Coronal ceCT image shows bilateral dural metastases.
Coronal ceCT image shows bilateral dural metastases.

Discussion

Metastases are present in up to 70% of patients with neuroblastoma at the time of diagnosis. Secondary craniocerebral neuroblastoma manifests most often as osseous metastases involving the calvaria, orbit, or skull base. Metastatic CNS neuroblastoma may also occur anywhere in the CNS as a parenchymal, intraventricular, or spinal cord mass.

Skull involvement

Metastatic involvement of the skull has been found in up to 25% of patients with neuroblastoma. Neuroblastoma is the most common malignant metastasis to the skull in children. These calvarial lesions often extend to produce epidural deposits.

Metastatic involvement of the skull produces several possible radiographic findings:

  • thickened bone,
  • the so-called “hair-on-end” periosteal reaction,
  • lytic defects,
  • separation of sutures.

The sutural separation secondary to direct involvement of neuroblastoma is different from that found with generalized increased intracranial pressure. In neuroblastoma, the sutural separation is not uniform and the margins of the sutures are somewhat indistinct. Extension of epidural deposits along the sutures produces erosion of the suture that then results in split sutures.

1-year-old boy with metastatic neuroblastoma. Axial CT image shows large lytic defect, resulting in separation of lambdoid suture, and indistinctness of sutures (arrows).

The hair-on-end appearance is a periosteal response to tumor cells extending from a calvarial metastasis. The inner aspect of the periosteum is particularly resistant to penetration by tumor cells so the tumor, as it breaks out of the bone, lifts the periosteum, thereby producing plaquelike epidural deposits of tumor. Skull metastases are often very subtle. Scalp lesions are a common accompaniment of calvarial metastases.

Dura involvement

Metastatic neuroblastoma has a predilection to metastasize to the dura. Dural metastases tend to favor the external surface of the dura, spreading diffusely over both the convexities and base of the skull. The dura acts as a barrier to direct invasion, so involvement of the brain parenchyma is rarely seen. Dural metastases are almost always associated with osseous metastases and can be hemorrhagic. Dural metastases may respond favorably to treatment.

DD

  • Langerhans cell histiocytosis
  • leukemia
  • lymphoma
  • sarcoma metastases

References

  1. D’Ambrosio N, Lyo JK, Young RJ, Haque SS, Karimi S. Imaging of metastatic CNS neuroblastoma. AJR Am J Roentgenol. 2010 May;194(5):1223-9. doi: 10.2214/AJR.09.3203.

Posted on 14.09.18

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