Magnetic resonance spectroscopy: a noninvasive diagnosis of gliomatosis cerebri

Gliomatosis Cerebri: Current Understanding and Controversies

Gliomatosis cerebri (GC) is a rare, extensively infiltrating glioma involving multiple contiguous lobes of the brain. This lethal disease affects all age groups, and the majority of patients have a poor outcome despite aggressive treatment. Despite its initial recognition in 1938, GC remains a controversial entity with little consensus in its definition, histology, or treatment. The majority of GC tumors are astrocytic, although mixed phenotypes have been identified. Treatment of GC is challenging as surgery is generally not an option due to the extensive areas of brain involved, the benefit of radiation therapy is unclear, and no chemotherapy has proven efficacy. Due to the rarity of the disease and its heterogeneity, both at histopathological and molecular levels, it is difficult to conduct clinical trials tailored for this diagnosis. This review summarizes our current knowledge, examines clinical studies focusing on the treatment of GC, highlights ongoing challenges, and discusses the recent molecular insights into adult and pediatric GC. We conclude that, although no longer recognized as a distinct pathological entity, GC represents a unique disease phenotype. Given the histologic and molecular overlap with other diffuse gliomas, the research emphasis should be on investigating its unique invasive biology.

Disseminated encephalomyelitis-like central nervous system neoplasm in childhood

A malignant neoplasm in the central nervous system with diffuse white matter changes on magnetic resonance imaging (MRI) is rare in children. It could be misdiagnosed as acute disseminated encephalomyelitis. This report presents our experience based on 4 patients (3 male, 1 female; aged 7-13 years) whose MRI showed diffuse lesions in white matter and who were initially diagnosed with acute disseminated encephalomyelitis. All of the patients received corticosteroid therapy. After brain biopsy, the patients were diagnosed with gliomatosis cerebri, primitive neuroectodermal tumor and central nervous system lymphoma. We also provide literature reviews and discuss the differentiation of central nervous system neoplasm from acute disseminated encephalomyelitis.

Marked response of gliomatosis cerebri to temozolomide and whole brain radiotherapy

Gliomatosis cerebri (GC) represents an unfortunate, rare variant of glioma with a very poor prognosis. Given this lesion's rarity, little information exists on appropriate treatment options. The diffuse, infiltrative nature of GC precludes any surgical resection and limits therapy. Because of the improved survival seen with the use of temozolomide (TMZ) in malignant glioma, a rigorous systematic review of the published literature was performed to ascertain the benefit of TMZ in GC. We identified all GC cases in the literature where there was enough information to ascertain a clear response to a specific chemoradiotherapeutic treatment. In addition to our experience with a recent case, we have identified 61 patients with GC in the published literature who demonstrated a positive radiographic or clinic response after treatment. Statistical analysis of survival was performed by Kaplan-Meier analysis. A positive radiographic and clinical response was seen in patients ranging in age from 4 to 84 years. Overall median survival in patients diagnosed with GC who demonstrated a response after treatment was 25 months, with 1- and 2-year survival rates of 89% and 55%, respectively. The most common treatment regimens for responders included TMZ alone (26.2%), external whole-brain radiotherapy (WBRT) (26.2%), and concomitant TMZ and WBRT (20%). Our patient was treated with concomitant TMZ (150 mg/m(2)/day over 5 days) and WBRT (50 Gy) and has remained with a complete radiographic response after 36 months. In conclusion, patients with GC confirmed by surgical biopsy should be aggressively treated with concomitant TMZ and WBRT, as marked responses have been seen, and this appears to offer overall survival benefit.

Gliomatosis cerebri, imaging findings of 12 cases

BACKGROUND AND PURPOSE

We report 12 cases of Gliomatosis cerebri (GC), a rare brain neoplasm, to define its semeiologic criteria. Literature was reviewed to clarify its physiopathology.

PATIENTS AND METHODS

From 1997 to 2008, 12 histologically proven cases with GC were retrospectively reviewed. Of the 12 patients, nine were male. The mean age was of 54 years. Were performed CT-Scan (n=6), MRI (n=12), diffusion and perfusion weighted images (n=12 and n=4), MR Spectroscopy (n=3), a FDG and a Methionin PET-Scan (n=2 and n=3 respectively).

RESULTS

Primary diagnosis was missed in six cases. Most frequent clinical signs were seizure and mental changes. Imaging criteria were: area of high signal intensity on FLAIR and T2-weighted images, involving three or more contiguous lobes with conserved architecture. Frequently a bilateral widespread invasion with involvment of the corpus callosum or the anterior white commissure or both was observed. At diagnosis and in the classical form (type I) of GC, no significant contrast enhancement and decreased rCBV were observed. Focal enhancement and increased rCBV were observed in the focal mass in type II GC. MR Spectroscopy showed an increase of the Cho/Cr ratio and a decrease in the NAA/Cr one. FDG PET showed in type I a decreased avidity for the FDG whereas in type II a increased avidity was observed. MET-PET showed an increased avidity for the tracer in a GC type II and a slight avidity in a GC type I.

CONCLUSION

GC is a rare brain entity. Primary diagnosis is often missed. The imaging findings of GC I, a WHO grade III tumor, should be known and include classical MRI but also PWI, MRS and scintigraphic findings.

Pitfalls in the diagnosis of brain tumours

Establishing the diagnosis of a brain tumour is not always a straightforward process. Many non-neoplastic neurological diseases can mimic brain neoplasms on neuroimaging or on histological examination, including multiple sclerosis, stroke, pyogenic abscess, toxoplasmosis, tuberculosis, cysticercosis, fungal infections, syphilis, sarcoidosis, Behçet disease, radiation necrosis, venous thrombosis, and others. Conversely, several types of brain neoplasms, such as glioblastomas, low-grade gliomas, CNS lymphomas, and brain metastases, can present in the absence of typical tumefactive lesions, posing significant diagnostic challenges. In this Review, we discuss the process of accurately establishing the diagnosis of brain tumours, focusing on pitfalls commonly encountered in clinical practice. We also discuss the rational use and limitations of new diagnostic techniques, such as diffusion-weighted MRI, perfusion-weighted MRI, magnetic resonance spectroscopy, single-photon emission tomography, and positron emission tomography, as well as new tools for histological examination, such as immunohistochemistry and molecular genetics analysis.