Annette C. Douglas-Akinwande MD, Presenter: Nothing to Disclose

Amr Mourad MD, Abstract Co-Author: Nothing to Disclose

Eyas M Hattab MD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to review the histology, CT and MRI characteristics of primary intracranial germinomas.

The presenting scans and histology of 21 patients with biopsy proven germinomas from 1989 to 2003 were retrospectively reviewed. Eighteen CT scan with contrast and 19 MRI scan with and without contrast were available.

Among the twenty one patients studied, there were 12 males and 9 females. The male to female ratio was 3:1in the pineal region but roughly equal in the neurohypophyseal region. The mean presenting age was 11.6 years with a range of 5 to 32 years. All germinomas were situated in the midline; 62% neurohypophyseal and 38% pineal region. Synchronous lesions in the pineal and neurohypophyseal regions were present in two patients. The lesions were all well circumscribed, with an average volume of 22.7cm3. The vast majority (90%) were heterogeneously enhancing on both CT and MRI. None of the neurohypophyseal germinomas demonstrated any calcification while most pineal germinomas (6/8) were calcified. 71% of all cases were partially cystic. On T1 and T2-weighted images the lesions were mainly isointense with variable components of hypo or hyperintensity. On FLAIR and proton density (PD) sequences the lesions were mostly isointense with or without smaller components of hyperintensity. On diffusion weighted (DWI) sequences, 60% were isointense, 33% hyperintense, and 7% hypointense.

In our series, intracranial germinomas were well circumscribed, lobulated lesions demonstrating mostly isointense signals on T1, T2, Flair, PD, DWI sequences. They showed a range of signal heterogeneity and enhanced heterogeneously. Calcifications were found exclusively in the pineal region. The heterogeneous imaging features may be a reflection of the histologic makeup of germinomas where lobules of large cells with round nuclei and prominent nucleoli are interlaced among various proportions of lymphocyte rich fibrous septae. Additionally, granulomas and microscopic foci of necrosis were frequent findings among this group of cases.

Douglas-Akinwande, A, Mourad, A, Hattab, E, Primary Central Nervous System Germinoma: Correlation of Magnetic Resonance and Computed Tomography Imaging Characteristics with Histologic Findings.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4409603.html