Recurrent Extraneural Metastatic Medulloblastoma in an Adult Presenting With a Superscan and Treated With Radium-223

Abstract

A 32-year-old man with medulloblastoma was initially treated with subtotal resection and craniospinal irradiation. He developed recurrent metastatic disease three years later with extensive bone-only metastases. Biopsy of the bone lesions confirmed metastatic medulloblastoma and restaging investigations demonstrated a superscan with no evidence of recurrence in the craniospinal axis. Extraneural metastatic medulloblastoma is rare, and the presentation with diffuse bone-only metastases with a superscan on imaging is unique. The patient had diffusely painful bone metastases requiring multiple hospitalizations for poor pain control. He declined chemotherapy and was treated with radium-223, an alpha particle emitting radionuclide therapy typically used in metastatic castrate-resistant prostate cancer. The patient received three out of a planned six cycles of radium-223 before it was discontinued due to myelosuppression requiring multiple blood transfusions, and restaging demonstrated local recurrence in the posterior fossa. This is the first report to our knowledge describing the use of radium-223 in a patient with extraneural bone-only metastatic medulloblastoma. Further research into the effect of radium-223 in patients with diffuse bone-only metastases from non-prostate cancer primary tumors is warranted.

Keywords: adult medulloblastoma; bone metastases; extraneural; metastatic medulloblastoma; radionuclide therapy; radium-223; superscan.

Figure 1. Contrast-enhanced axial CT scan demonstrating a mass in the left cerebellum.

CT, computed tomography

Figure 2. Preoperative MRI: (A) Gadolinium-enhanced T1-weighted and (B) T2-weighted axial images demonstrating a non-enhancing lobulated mass in the left cerebellum.

MRI, magnetic resonance imaging

Figure 3. High-power microscopy image of medulloblastoma demonstrating small, round blue cells with diffuse tumor growth pattern.

Figure 4. Postoperative MRI: (A) T2-weighted and (B) diffusion-weighted axial images demonstrating residual tumor in the anterior and medial resection cavity.

MRI, magnetic resonance imaging

Figure 5. (A) A superscan demonstrating diffuse heterogeneously increased activity in the axial and appendicular skeleton with associated soft tissue and renal suppression; (B) a restaging bone scan demonstrating a persistent superscan; however, with the heterogeneity of bone remodeling in the lower thoracic spine and distal left femur consistent with disease improvement.

Figure 6. Restaging MRI. Gadolinium-enhanced T1-weighted (A) axial and (B) coronal images of the brain demonstrating local recurrence within the vermis.

MRI, magnetic resonance imaging