Four months later, a follow-up study revealed significant interval progression of the disease. There was an increase in size of the extra-axial metastases, with diffuse permeative calvarial bone destruction and periosteal reaction. The sutures were now widely separated because of the mass effect of the metastases (Figure 2A). Additionally, the scan revealed the development of a large right frontal lobe hematoma, with extension into the ventricles. Subsequent midline shift with subfalcine herniation was present (Figure 2B). Further tumor progression was evidenced by bilateral extraconal orbital extension, causing bilateral proptosis (Figure 2C).
Clinical presentation depends on the extent and location of disease. Most patients present with an abdominal mass, which may be accompanied by constitutional symptoms of fever, weight loss, and malaise. Since neuroblastoma has the propensity for increased catecholamine production, symptoms may include flushing, hypertension, diaphoresis, tachycardia, intractable diarrhea, and hyperglycemia. If the tumor invades the neural foramina and compresses a nerve, peripheral nerve deficits can appear. Orbital metastatic disease may result in proptosis or ecchymosis. Additionally, more than half of neuroblastoma patients have osseous metastatic disease at the time of diagnosis, which can manifest as Hutchinson syndrome if limping and irritability are present.1
CT is the most common modality for radiographic assessment of neuroblastoma. Typical findings include a large, irregularly shaped, heterogeneous adrenal mass, which often contains areas of necrosis, hemorrhage, and calcification.3 The tumor has a tendency to infiltrate around regional structures rather than displace them.1 Adenopathy and vascular encasement without actual invasion are also characteristic findings.1 Other radiographic manifestations of the disease depend on tumor origin and extent and location of disease.
Unfortunately, metastatic disease is common in neuroblastoma, often causing symptoms that prompt medical attention. Common places for neuroblastoma to metastasize to are cortical bone, bone marrow, and lymph nodes. In addition, orbital, liver, and skin metastases are frequently observed, which may lead to proptosis, hepatomegaly, and dark blue skin masses (also known as "blueberry muffin syndrome"), respectively. Less common areas of metastatic disease include the dura mater, lung, and brain.2 Usually, if intra-axial CNS involvement is seen, it is a result of an extension from extra-axial lesions (eg, from the dura or orbits).2,4-6 Isolated parenchymal disease is rare, although the incidence has been rising with the introduction of improved chemotherapeutic regimens and observed prolonged survival rates.2,5
The patient in this case demonstrated the classic radiographic findings of metastatic CNS disease, which was originally exclusively in the extra-axial compartment and manifested as extensive dural metastases. On the subsequent head CT, the expected findings of progressive disease were shown with increased dural metastastic bulk, intra-axial extension with cerebral and intraventricular hemorrhage, and orbital metastases that caused proptosis. The impressive sutural diastases were sequelae of the growing dural metastases that exerted progressively increasing pressure at the suture line.5 If this feature is seen on imaging, the differential diagnosis is short and includes metastatic neuroblastoma, leukemia, and lymphoma.1
Survival rates depend on the staging of disease. Stage I tumors are limited to the organ of disease without metastases. Stage II tumors have spread locally but have not crossed the midline. Stage III tumors have extended across the midline. Stage IV tumors show evidence of distant metastatic disease. A special subset of stage IV has been designated as stage IVS, which has distant metastases to the liver, skin, and bone marrow, without evidence of skeletal metastases in children younger than 1 year. Stage IVS infers a much better prognosis, similar to that of stage I disease.5
Neuroblastoma CNS metastates are not uncommon to the dura or orbits. Common CT manifestations include dural infiltration of the disease, which may lead to sutural diastasis. When this finding is present, the differential includes metastatic neuroblastoma, lymphoma, and leukemia. Orbital metastatic disease usually presents as a mass in the extraconal space with resultant proptosis. If intra-axial extension occurs, hemorrhage is often present within the tumor. CNS metastatic disease is stage IV neuroblastoma, which infers a poor prognosis.
Metastatic neuroblastoma. Appl Radiol.