A case of melanotic desmoplastic ganglioglioma

Ex vivo tissue imaging for radiology-pathology correlation: a pilot study with a small bore 7-T MRI in a rare pigmented ganglioglioma exhibiting complex MR signal characteristics associated with melanin and hemosiderin

To advance magnetic resonance imaging (MRI) technologies further for in vivo tissue characterization with histopathologic validation, we investigated the feasibility of ex vivo tissue imaging of a surgically removed human brain tumor as a comprehensive approach for radiology–pathology correlation in histoanatomically identical fashion in a rare case of pigmented ganglioglioma with complex paramagnetic properties. Pieces of surgically removed ganglioglioma, containing melanin and hemosiderin pigments, were imaged with a small bore 7-T MRI scanner to obtain T1-, T2-, and T2*-weighted image and diffusion tensor imaging (DTI). Corresponding histopathological slides were prepared for routine hematoxylin and eosin stain and special stains for melanin and iron/hemosiderin to correlate with MRI signal characteristics. Furthermore, mean diffusivity (MD) maps were generated from DTI data and correlated with cellularity using image analysis. While the presence of melanin was difficult to interpret in in vivo MRI with certainty due to concomitant hemosiderin pigments and calcium depositions, ex vivo tissue imaging clearly demonstrated pieces of tissue exhibiting the characteristic MR signal pattern for melanin with pathologic confirmation in a histoanatomically identical location. There was also concordant correlation between MD and cellularity. Although it is still in an initial phase of development, ex vivo tissue imaging is a promising approach, which offers radiology–pathology correlation in a straightforward and comprehensive manner.

Supratentorial tumors typical of the infantile age: desmoplastic infantile ganglioglioma (DIG) and astrocytoma (DIA). A review

OBJECT

Desmoplastic infantile gangliogliomas (DIGs) and desmoplastic infantile astrocytomas (DIAs) are tumors typical of the infantile age. A large size, with a mixed solid and cystic component, clinical presentation with progressing signs of increased intracranial pressure, a prominent benign desmoplastic structure at histological examination, and a favorable clinical course in the majority of cases are the prominent features of these tumors. The objective of the present paper was to review the pertinent literature on the topic together with our personal experience, with the aim of an updated review of the subject.

RESULTS AND CONCLUSIONS

Only 28 papers are present in the literature devoted to DIGs and DIAs, most of them reporting on single cases or small series, with a total of 107 patients aged from 5 days to 48 months with a slight male prevalence. Most of the reported cases refer to supratentorial and hemispheric locations, a few cases involving the hypothalamic region, the posterior fossa, and the spinal cord. The typical MRI appearance is of large mixed solid and cystic tumors with a spontaneous hyperintense T2 appearance of the solid part which also shows a strong contrast enhancement. Mixed ganglionic and astrocytic cells are identifiable in DIGs, whereas DIAs are typically featured by the exclusive presence of glial cells. In both cases, more primitive cells may be observed, which present a higher number of mitoses and these areas can mimic the features of malignant astrocytomas. Surgery represents the treatment of choice; however, radical removal has been reported as possible only in around 30 % of the cases: the low age of the patients together with their low weight and the large size of and the hyper-vascularized structure of the tumors represent the main factors limiting surgery. Pure observation is considered as first choice in children undergoing a partial/subtotal tumor resection, chemotherapic regimens being considered in cases of recurrences after a second look surgery. Long-term prognosis is favorable with mortality being related mostly to the rare midline (i.e., hypothalamic) locations, which beyond the functionally relevant site, tend to have an unusually more aggressive histological behavior.

Melanosomal melanin pigment in pleomorphic xanthoastrocytoma, evidence for neuronal-glial origin: A case report with review of the literature

We describe a unique case of pleomorphic xanthoastrocytoma (PXA) in a 19-year-old male presenting with the chief complaint of seizures. On radiology, the tumor was located in the temporal lobe. It was cortically based and solid cystic in nature. Light microscopy showed pleomorphic large polygonal cells with inclusions, nuclear clustering, lipidization, and foamy cytoplasm intermingled with spindle cells arranged in sweeping pattern and focally containing cytoplasmic brownish black pigment. The pigment stained black with Fontana-Masson stain and bleached with potassium permanganate. Gomori silver stain showed reticulin fibers surrounding individual tumor cells as well as groups of cells. On immunohistochemistry, tumor cells were positive for GFAP, S-100 and focally for synaptophysin and CD34 but negative for HMB-45. CD34 revealed a specific membranous pattern around individual cells as well as groups of cells along the fibers replicating a reticulin pattern. The ultrastructural examination showed supporting melanosomes, thus confirming the melanin pigment. Sequencing for BRAF V600E showed a heterozygous mutation. To our knowledge only five cases of PXA with melanin pigment have been reported and none of which described BRAF V600E mutation analysis. This case provides further insight into the origin and pathogenesis of pigmented astrocytic tumor, additionally highlighting the characteristic CD34 staining pattern.

Clinical analysis of primary melanotic ependymoma in the central nervous system: case series and literature review

BACKGROUND

Melanotic ependymoma (ME) is an extremely rare subset of ependymoma characterized by cytoplasmic and extracellular deposition of melanin, with no case series having been reported to date. The aim of this study was to analyze the clinical manifestations, pathological and radiological features, treatment, and follow-up data, and to discuss the diagnosis, management and prognosis of ME.

METHODS

We retrospectively reviewed the clinical and imaging data of six patients with primary ME. The diagnosis was based on radiological and pathological criteria. All the patients were treated surgically with gross total resection. The preoperative and postoperative neurological states of the patients were analyzed. All the follow-up data were obtained from office visits, and the long-term outcomes are presented and discussed.

RESULTS

Patients presented with nonspecific symptoms. On magnetic resonance imaging (MRI), although a characteristic signal variation could be found reflecting the melanin component, individual appearances varied widely and were related to the content and distribution of melanin in the ME lesions. The characteristic ependymoma-related pathological appearance and specific immunostaining for glial fibrillary acidic protein and antimelanoma monoclonal antibody were revealed. During a mean follow-up period of 46.8 months, no local recurrences or distant metastases were observed.

CONCLUSIONS

The accurate diagnosis of ME depends on pathology. The histological grading used for ependymoma can be applied. Most MEs have a relatively benign course. Complete surgical resection alone is the treatment of choice for low-grade MEs, and the outcome may be favorable. Postoperative adjuvant radiotherapy can be considered for lesions with histologically anaplastic features.

23-year-old man with a superficial cortical brain tumor

A 23-year-old male presented with a tonic-clonic generalized seizure. Neuroradiological examination revealed a superficial cystic mass with a mural nodule in the right fronto-parietal lobe. Histological and immunohistochemical examination were consistent with a pigmented (melanin producing) desmoplastic ganglioglioma.These tumors have been first described in childhood, one of them displaying melanin deposits. Only twenty cases of non-infantile desmoplastic gangliogliomas have been reported in the literature, none of them pigmented. According to the clinical and histomorphology (including the desmoplastic component) features, the differential diagnosis should include the ganglioglioma, the xanthoastrocytoma pleomorphic (both tumors also with pigmented forms) and the superficial desmoplastic infantile astrocytoma.

Desmoplastic infantile and non-infantile ganglioglioma. Review of the literature

Desmoplastic gangliogliomas (DIG) are rare primary neoplasms that comprise 0.5-1.0% of all intracranial tumors. Clinically, there are two forms of DIG, the infantile and the non-infantile. These tumors invariably arise in the supratentorial region and commonly involve more than one lobe, preferentially the temporal and frontal. On neuroimaging are seen as large hypodense cystic masses with a solid isodense or slightly hyperdense superficial portion. The histologic diagnosis is characterized by the presence of three different cell lines: astrocytic, neuronal, and primitive neuroectodermal marker sites, which were demonstrable. The treatment of choice is radical surgical excision, and if this is done, achieved complete healing of the patient does not require additional treatment. A literature review of DIG was compiled through Medline/Ovid using the keywords "desmoplastic infantile ganglioglioma", "desmoplastic non-infantile ganglioglioma" covering the years 1984-2009. We present a review of a total of 113 cases of infantile (94) and non-infantile gangliogliomas (19) published to date, examining the clinical, radiologic, surgical, and pathological aspects, as well as the outcome. Desmoplastic gangliogliomas represent a rare tumor group with two well-defined age groups, the children and non-children. Desmoplastic infantile gangliogliomas are the most common and occur in children below 5 years of age, and the large majority of them present within the first year of life. Surgery is the treatment of choice and no complementary treatment is needed in cases of complete tumor resection.