Leptomeningeal Dissemination of Pilocytic Astrocytoma Via Hematoma in a Child

Masaru Kanda, M.D., Hidenobu Tanaka, M.D., Ph.D., Soji Shinoda, M.D., Ph.D., and Toshio Masuzawa, M.D., Ph.D.

Disclosures

Neurosurg Focus. 2002;13(1) 

In This Article

Abstract and Introduction

A case of recurrent pilocytic astrocytoma with leptomeningeal dissemination (LMD) is described. A cerebellar tumor was diagnosed in a 3-year-old boy, in whom resection was performed. When the boy was 6 years of age, recurrence was treated with surgery and local radiotherapy. At age 13 years, scoliosis was present, but the patient was asymptomatic. Twelve years after initial surgery LMD was demonstrated in the lumbar spinal region without recurrence of the original tumor. This tumor also was subtotally removed. During the procedure, a hematoma was observed adjacent to the tumor, but the border was clear. Histological examination of the spinal cord tumor showed features similar to those of the original tumor. There were no tumor cells in the hematoma. The MIB-1 labeling index indicated no malignant change compared with the previous samples. Radiotherapy was performed after the surgery. The importance of early diagnosis and management of scoliosis is emphasized, and the peculiar pattern of dissemination of the pilocytic astrocytoma and its treatment are reviewed.

Juvenile pilocytic cerebellar astrocytoma is a benign tumor that corresponds to histological Grade I.[6,7,9] It is associated with 10- and 20-year survival rates of greater than 90% in patients who undergo total excision of the lesion.[6,7,10,21] Many of these tumors are amenable to total resection, and the subsequent recurrence rates. Even in children in whom tumors are subtotally excised and radiotherapy is then performed, the 20-year survival rates are often between 70 and 80%.[21]

Histopathologically, an astrocytic tumor of low cellularity exhibits a biphasic pattern with varying proportions of compacted bipolar cells with Rosenthal fibers and loose textured multipolar cells with microcysts and granular bodies.[9] Anaplastic transformation is unusual; some authors have suggested that it is induced by radiotherapy.[9,20] A small percentage of these tumors manifest widespread dissemination either at presentation or later. Furthermore, fewer than 10 cases of LMD from a pilocytic cerebellar astrocytoma have been reported;[1,5,8,9,10,11,13,14,16,18,19,20] in five of these cases, the metastasis was spinal.[1,5,8,9,10,12,14,16,17,18] The detection of dissemination of a histologically benign neoplasm raises fundamental questions regarding the biological features that account for tumor seeding, as well as practical concerns regarding the long-term outcome after treatment.[15]

When scoliosis is first diagnosed during childhood, it is classified into one of three categories: congenital, paralytic, or idiopathic. The congenital variety is a result of vertebral malformation present since birth. The paralytic type is suggested by a history of obvious neurological disease. A diagnosis of idiopathic scoliosis, on the other hand, must remain one of exclusion. It appears that when scoliosis is the main presenting feature in a case of a spinal cord tumor, its cause is often overlooked.[3,4,15,17]

The case reported here is unusual in that, 12 years after surgery, a histologically benign astrocytoma disseminated to the spinal regions without pathologically malignant transformation or apparent regrowth of the primary tumor. In addition, intraoperative examination demonstrated a hematoma adjacent to the tumor. The goals of the present report are to emphasize the importance of MR imaging both at presentation and during the follow-up course in patients with these conditions, as well as to alert the clinician to consider a diagnosis of intramedullary tumor in patients in whom scoliosis is evident at an early stage.

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