Diffuse mixed type osseous metastases of medulloblastoma in an adult: MR imaging findings Banu Yagmurlu *, Gulden Akyar, Suat Fitoz Department of Radiology, Ankara University, Medical School, Ibni Sina Hospital, Samanpazarı 06100, Sıhhiye Ankara, Turkey Received 4 February 2002; received in revised form 28 February 2002; accepted 1 March 2002 Abstract Medulloblastoma is a relatively common intracranial neoplasm in childhood, but is a rare condition in adult group. This tumor has a well-known tendency to seed along cerebrospinal fluid pathways; however, extraneural metastases are uncommon and have typically been associated with a fatal outcome. When extracranial metastases occur, most common site of involvement is bone (80%), especially pelvis, long bones and spine. Radiographically, blastic (sclerotic) metastases are most common (60%), but lytic (35%) and mixed patterns (5%) also do occur [Clin. Imaging 15 (1991) 286]. In this paper we present a case of medulloblastoma metastatic to bone involving almost the whole skeleton and describe the magnetic resonance appearance, with emphasis on the imaging findings of mixed (both lytic and sclerotic) forms. # 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Medulloblastoma; Osseous metastasis; MRI; CT The patient presented with headaches, vomiting and ataxia at the age of 27. A contrast-enhanced computed tomography (CT) scan of the head demonstrated a large enhancing mass in the left hemisphere of the cerebellum obliterating the fourth ventricle and causing obstructive hydrocephalus. At surgery, a large tumor filling the fourth ventricle was removed totally and a ventriculo- peritoneal (V-P) shunt was placed. Histopathological examination of the specimen revealed medulloblastoma. Postoperatively, the patient had been given both radio- therapy and chemotherapy. He did well for 8 years with no evidence of recurrence on follow-up CT scans of the brain. He had no other complaints until he developed low back pain in 1998. Plain films of the lumbar spine showed diffuse lytic /sclerotic lesions of the vertebral bodies and posterior elements throughout the whole spine (Fig. 1a). Similar mixed lesions are detected in the long bones including femur and humerus bilaterally. Radiograph of the chest revealed multiple rib involve- ment. CT scans of the spine and pelvis demonstrated the lytic  /sclerotic nature of the lesions in detail (Fig. 1b), and a magnetic resonance (MR) examination of the pelvis and the lumbar spine was performed with a 1.5 T Signa Horizon unit to determine whether a soft tissue component exists (GE Medical Systems, Milwaukee, Wisconsin). T1-weighted spin-echo (TR/TE: 600/11 msec) and T2-weighted fast spin-echo (TR/TE: 6000/85 ms) images with fat suppression of the pelvis and lumbosacral region were acquired. Sclerotic components of the lesions showed low signal intensity on both T1- and T2-weighted images (Fig. 2). Expansile-lytic com- ponents were hypointense on T1-weighted images and became more conspicuous on fat-saturated T2-weighted images with high signal intensity. The intramedullary involvement was so extensive that normal fatty bone marrow was hardly detected on T1-weighted images of the pelvis and spine (Fig. 3). No extramedullary exten- sion was detected. CT of the thorax and abdomen, also sonography of the abdominopelvic region were normal, lacking signs of metastasis. The described findings presumed metastatic bone disease, and a biopsy of the ischium was performed. Histopathological examination was reported as primi- tive neuroectodermal tumor characterized by small, * Corresponding author. Tel.:  /90-312-310-3333/2888; fax:  /90- 312-310-0808 E-mail address: byagmurlu@tr.net (B. Yagmurlu). European Journal of Radiology Extra 45 (2003) 33  /36 http://intl.elsevierhealth.com/journals/ejrx 1571-4675/03/$ - see front matter # 2002 Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S1571-4675(03)00020-8