Diffusion-Weighted Magnetic Resonance Imaging and ADC Maps in the Diagnosis of Intracranial Cystic or Necrotic Lesions. A Retrospective Study on 49 Patients.

This study evaluated the usefulness of diffusion-weighted (DW) magnetic resonance imaging (MRI) and ADC maps in the differential diagnosis of brain abscesses from cystic or necrotic neoplasms. MR images of 49 patients with 54 lesions were examined retrospectively. All patients underwent conventional MRI and DWI, and ADC values were calculated by placing ROIs of 30 mm(2) manually over the cystic part of the lesions. On DWI, all cystic portions of abscesses were hyperintense. Mean ADC values were 0.48×10 mm(2)/s (range 0.41-0.54×10 mm/s) for pyogenic abscesses, 0.73×10 mm(2)/s (range 0.65-0.91×10 mm/s) for mycotic abscesses and 0.6 mm(2)/s for Nocardia abscess. Cystic areas appeared hypointense on DWI in 33/44 tumours (mean value ADC 1.96 mm(2)/s). Eleven tumours (11/44) appeared hyperintense on DWI: eight metastases from lung cancer (mean ADC value 0.86 mm(2)/s, range 0.75-1.2 mm(2)/s), two GBMs (mean 0.7 mm(2)/s, range 0.67-0.76 mm(2)/s) and one anaplastic astrocytoma (ADC value 1.24 mm(2)/s). ADC values may help in differentiating pyogenic abscess from brain tumors or metastatic lesions.

Primitive cerebral melanoma: case report and review of the literature.

BACKGROUND: Central nervous system primary malignant melanoma accounts for approximately 1% of all the cases of melanoma; reports in the literature are relatively rare. CASE DESCRIPTION: A 74-year-old man was hospitalized because of an episode of aphasia. The neuroradiologic examinations demonstrated a round homogeneous lesion extending near the left sylvian fissure. He had no extracranial abnormalities. The patient underwent a neurosurgical procedure and the tumor was macroscopically totally excised. Pathological examination of the surgical specimen revealed a histological appearance similar to that of melanoma. A diagnosis of primary CNS melanoma was made after careful dermatologic and ophthalmologic examination, which ruled out presence of cutaneous or choroidal melanoma. The patient did not receive any further treatment and he is free of disease 2 years after diagnosis. CONCLUSIONS: We report a case of primary cerebral melanoma of the left temporal lobe; clinical, neuroradiological, and histological findings are discussed with review of the literature. Primary melanoma of the CNS may present either with localized intra/extra-axial mass lesions or with meningeal spread, which carries a worse prognosis. The prognosis of cerebral primitive melanoma is variable, although it is common opinion that primitive cerebral melanoma has a better prognosis than cutaneous melanoma, with two cases in the literature surviving 9 and 12 years.