[Diffuse bone marrow metastasis in cerebellar high-grade astrocytoma. A case report]. / Metastasis difusa de la medula osea en un astrocitoma cerebeloso de alto grado. Un caso clinico.

INTRODUCTION: Cerebellar high-grade astrocytoma is uncommon. Although more prone to present cerebrospinal fluid dissemination, the cerebellar location is not particularly related to the occurrence of extra-cranial metastases, which are also unusual in supratentorial malignant gliomas. CASE REPORT: A 46 year-old man with cerebellar anaplastic astrocytoma who developed pancytopenia due to extensive bone marrow metastases. CONCLUSION: Extraneural metastases of brain gliomas are rare and the spread to the bone marrow confers an extremely poor prognosis for these patients. The expected improvement in glioma patients' survival due to the combination of more efficient therapies may lead to an increased incidence of this uncommon presentation, justifying a more rigorous follow-up of systemic manifestations.

MRI of medulloblastoma in adults.

Medulloblastoma has variable appearances on MRI in both children and adults. Adults are more likely to have heterogeneous cerebellar hemisphere tumours, and this is thought to be related to the greater prevalence of desmoplastic tumours in adulthood. Few studies have addressed the MRI features of adult medulloblastoma and the specific characteristics of desmoplastic and classic tumours have not been analysed. Our aim was to analyse the imaging characteristics of desmoplastic (DM) and classic (CM) medulloblastomas in adult. We retrospectively studied preoperative MRI of six men and three women, median age 33 years, range 23-53 years, with pathologically proved medulloblastomas. There were six (67%) with DM. The tumour was in the cerebellar hemisphere in eight patients (89%), including the three with CM, one of which was bilateral. All tumours were heterogeneous, giving predominantly low or isointense signal on T1- and isointense signal on T2-weighted images. Cystic or necrotic areas in all patients were particularly visible on T2-weighted images. Contrast enhancement was absent in one DM and varied from slight to intense in eight (three CM), homogeneous in one DM and patchy in seven. All tumours extended to the surface of the cerebellum and two had well-defined margins. MRI does not allow a clear distinction between DM and CM in adults.