Imaging findings of CNS atypical teratoid/rhabdoid tumors.

Four patients with brain tumors were diagnosed with atypical teratoid/rhabdoid tumors and underwent CT and MR imaging. For all tumors, aggressive features were shown by imaging studies and included hydrocephalus, apparent invasion of the adjacent brain and dura, and marked mass effect. The striking heterogeneity of the atypical teratoid/rhabdoid tumor shown by imaging studies reflects the histopathologic complexity of these tumors, and awareness of atypical teratoid/rhabdoid tumor is important in making the correct diagnosis of this uncommon but probably underdiagnosed entity.

MR imaging characteristics of pilomyxoid astrocytomas.

BACKGROUND AND PURPOSE: Pilomyxoid astrocytoma (PMA) is a recently described tumor that typically occurs in the chiasmatic-hypothalamic region in young children and has unique histopathologic and clinical characteristics. These tumors have been previously diagnosed as pilocytic astrocytoma (PA). PMA appears to have a higher rate of recurrence and CSF dissemination than typical PA. METHODS: We analyzed MR findings in four patients with PMA and compared them with those of typical chiasmatic-hypothalamic PA. RESULTS: MR findings of PMA were chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity that extended into the deep white and gray matter, and CSF dissemination. CONCLUSION: Larger series are needed before the MR imaging findings of chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity extending into the deep white and gray matter, and CSF dissemination can be used in the differential diagnosis of such tumors.

Is there a requirement for adjuvant therapy for choroid plexus carcinoma that has been completely resected?

Choroid plexus carcinomas (CPC) are rare central nervous system malignancies. While attempted surgical resection is imperative, the benefit of adjuvant therapy, particularly in the setting of a gross total resection (GTR), is unclear. We reviewed all pediatric cases of CPC reported in the literature between 1985 and 2000. Seventy-five cases of CPC were identified. Mean age at the time of diagnosis was 26 months. Thirty-seven patients had a GTR and 38 patients had a subtotal resection (STR). Thirty-eight cases (51%) were alive and 37 cases (49%) were deceased at time of publication. For cases with a GTR, survival was 84% compared to an 18% survival for patients with a STR. For patients with a GTR, all forms of adjuvant therapy were statistically equivalent. Our retrospective literature review confirms the importance of GTR in the therapy of CPC, with GTR alone being the single most important predictor of survival. The prognosis is poor for any patient with a STR, with the exception of those patients for whom adjuvant therapy allowed for an eventual GTR. The small number of patients receiving a GTR and no further therapy precluded a statistical comparison of no therapy in the setting of a GTR versus any form of adjuvant therapy. However, all four of these patients are alive, raising the possibility that adjuvant therapy in the setting of a GTR may not be required.