Dysplastic gangliocytoma of cerebellum in a newborn. Case report

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) presenting as a prenatally heterotopic hamartoma

Dysplastic gangliocytoma of the cerebellum (DGC), also called Lhermitte-Duclos disease, is a rare lesion of the posterior fossa consisting of a diffuse hypertrophy of the cerebellar cortex. DGC frequently presents in young adults and rarely in childhood. Only 3 cases have been previously described in newborns. We present an uncommon case of DGC which was diagnosed in utero. The radiological presentation prenatally and at birth was similar to a heterotopic neuroglial brain tissue. MRI aspects evolved from T1/T2 isointense signals to hypoT1 and hyperT2 signals at the age of 1 year. The girl was then operated on total removal of the lesion which was performed with no postoperative complication. Genetics did not demonstrate any germline PTEN mutation or family history suggesting Cowden disease. Two years later, the child was doing well and MRI confirmed complete resection. This case illustrates the difficulties of diagnosing intracranial lesions in foetuses and newborns. Physicians caring for pregnant women and pediatrics should be aware that neoplasm-like lesions such as DGC may present as hamartomas. Surgical resection could then be discussed whenever possible.

Lhermitte-Duclos Disease in Pediatric Population: Report of 2 Cases

INTRODUCTION

Lhermitte-Duclos disease (LDD), also known as dysplastic cerebellar gangliocytoma, is an uncommon disorder in children, characterized by being a slow-growing lesion of the posterior fossa, which mainly affects the granular cell layer of the cerebellar parenchyma and may be associated with other multiple hereditary hamartomas and neoplasms.

CASE PRESENTATION

We report 2 cases of LDD in pediatric patients and describe clinical symptoms and radiological and histopathological characteristics. In addition, we analyzed the relation to Cowden Syndrome based on the International Cowden Syndrome Consortium Operational Criteria and the most updated guidelines by the National Comprehensive Cancer Network (NCCN Guidelines Version 1.2020).

CONCLUSION

LDD is a very rare disease in childhood but should be considered in the differential diagnosis of posterior fossa lesions. LDD can mimic low-grade glial tumors or infectious diseases. Patients develop late clinical manifestations due to the slow-growing pattern, and conservative treatment with outpatient follow-up may be an option in asymptomatic children.

The Lhermitte-Duclos disease: a rare bilateral cerebellar location of a rare pathology

Dysplastic gangliocytoma or Lhermitte-Duclos disease is a rare disorder characterized by a slowly progressive unilateral tumour mass of the cerebellar cortex. It is probably hamartomatous, although the exact pathogenesis remains unknown. Lhermitte-Duclos disease was recently encountered to be part of a multiple hamartoma-neoplasia complex (Cowden's syndrome). It typically presents in young adults, although it has been encountered at all ages. We present the case of bilateral cerebellar location of this pathology in a 50-year-old man presented with a progressive onset and worsening of headaches accompanied by nuchal rigidity, photophobia and nausea awakening each morning. Upon physical examination, the patient was awake with a discrete right vestibular syndrome made of positive Romberg without nystagmus. Magnetic Resonance Imaging (MRI) was performed and revealed salient “tiger stripe” appearance of the bilateral cerebellar cortex relevant to a Lhermitte-Duclos disease.

Lhermitte-Duclos disease: A case report with radiologic-pathologic correlation

Background: Lhermitte-Duclos disease (LDD) stems from the development of a rare benign lesion of uncertain pathogenesis that distorts the normal cerebellar laminar cytoarchitecture. We explored the lesion's appearance on conventional magnetic resonance imaging (MRI) combined with susceptibility-weighted imaging, diffusion-weighted imaging, perfusion imaging, or arterial spin labeling. Although many cases of LDD have been previously reported in the literature, the radiologic-pathologic correlation has been described in only a few of these cases. To the best of our knowledge, this is the first case report to provide detailed information about the radiologic-pathologic correlation of LDD. Case Report: A 48-year-old woman presented with left facial tics, occipital headache, and dizziness for 1 month. MRI revealed a left cerebellar lesion with hypointensity on T1-weighted images. On T2-weighted images, the mass was hyperintense with tigroid appearance due to alternating high and normal signal intensities. High signal intensity was noted on fluid-attenuated inversion recovery images. Magnetic resonance spectroscopy indicated decreased level of choline (Cho), N-acetyl aspartate, and myoinositol with elevated level of lactate on the affected side. The lesion showed a bright signal on diffusion-weighted images, whereas apparent diffusion coefficient mapping revealed no disturbance of diffusion. The pathology of the excised lesion was consistent with LDD. Conclusion: MRI with advanced techniques can provide not only preoperative diagnosis but also better pathologic correlation.

Lhermitte-Duclos disease (dysplastic cerebellar gangliocytoma): a malformation, hamartoma or neoplasm?

OBJECTIVES

Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare disorder, characterized by a slowly progressive unilateral tumour mass of the cerebellar cortex. The fundamental nature of this apparently benign entity and in particular its pathogenesis remain unknown. The debate, whether it represents a neoplastic, malformative or hamartomatous lesion, is still in progress. Lhermitte-Duclos disease was recently encountered to be part of a multiple hamartoma-neoplasia complex (Cowden's syndrome).

METHODS

The present account gives a review of the pertinent literature with emphasize on clinical presentation, radiological findings, surgical procedures, histopathological features and pathogenetic considerations of dysplastic cerebellar gangliocytoma.

RESULTS

Dysplastic cerebellar gangliocytoma clusters within the third to fourth decades of life. Cranial nerve palsies, unsteadiness of gait, ataxia and sudden neurological deterioration as a result of occlusive hydrocephalus are frequent signs and symptoms. Associations with other congenital malformations, such as megalencephaly, polydactylia, multiple haemangioma and skull abnormalities are common. Magnetic resonance imaging (MRI) is the diagnostic modality of choice and reveals characteristic non-enhancing gyriform patterns with enlargement of cerebellar folia. Surgery is the therapeutic procedure generally performed and complete resection was attempted in the majority of cases. The histopathological findings of Lhermitte-Duclos disease include widening of the molecular layer, which is occupied by abnormal ganglion cells, absence of the Purkinje cell layer and hypertrophy of the granule cell layer.

CONCLUSIONS

Dysplastic gangliocytoma of the cerebellum is of benign behaviour and its incidence is extremely rare. The disease should be considered when confronted with a young adult presenting with clinical signs of progressive mass effect in the posterior fossa. The lesion is hypointense on T1- and hyperintense on T2-weighted magnetic resonance images. Recognition of the disease is of particular importance, as the frequent but under-reported coexistence with Cowden syndrome, should prompt thorough clinical and apparative investigation to detect or exclude concomitant malignancies.

Deletion of Pten in mouse brain causes seizures, ataxia and defects in soma size resembling Lhermitte-Duclos disease

Initially identified in high-grade gliomas, mutations in the PTEN tumor-suppressor are also found in many sporadic cancers and a few related autosomal dominant hamartoma syndromes. PTEN is a 3'-specific phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) phosphatase and functions as a negative regulator of PI3K signaling. We generated a tissue-specific deletion of the mouse homolog Pten to address its role in brain function. Mice homozygous for this deletion (PtenloxP/loxP;Gfap-cre), developed seizures and ataxia by 9 wk and died by 29 wk. Histological analysis showed brain enlargement in PtenloxP/loxP;Gfap-cre mice as a consequence of primary granule-cell dysplasia in the cerebellum and dentate gyrus. Pten mutant cells showed a cell-autonomous increase in soma size and elevated phosphorylation of Akt. These data represent the first evidence for the role of Pten and Akt in cell size regulation in mammals and provide an animal model for a human phakomatosis condition, Lhermitte-Duclos disease (LDD).

From the archives of the AFIP: superficial gliomas: radiologic-pathologic correlation. Armed Forces Institute of Pathology

Glial neoplasms that are peripherally located and involve the cortical gray matter are noteworthy because of their predilection to serve as a seizure locus, their amenability to surgical resection, their generally favorable prognosis, and their characteristic imaging features, which facilitate diagnosis before surgery. The smaller lesions include ganglioglioma and dysembryoplastic neuroepithelial tumor. Gangliogliomas contain both neuronal and glial components and occur most commonly in the temporal lobe. Variant forms of gangliogliomas may occur and are related to the different compositions of the underlying cellular population. Gangliocytomas lack glial cells and are located both in the cerebral hemispheres and the cerebellum. Lhermitte-Duclos disease represents a specific type of cerebellar gangliocytoma with dysplastic features and is characterized by a laminar pattern at imaging. Dysembryoplastic neuroepithelial tumors occur predominantly in children and young adults with partial seizures and most commonly arise in the temporal lobe, frequently in combination with cortical dysplasia. Surrounding vasogenic edema is conspicuously absent in both gangliogliomas and dysembryoplastic neuroepithelial tumors. The larger masses in this group include desmoplastic infantile ganglioglioma and pleomorphic xanthoastrocytoma and tend to involve the leptomeninges and cortical territory. Both invoke an intense desmoplastic reaction, which appears as an enhancing soft-tissue component at imaging.

Lhermitte-Duclos disease (Dysplastic gangliocytoma of the cerebellum)

OBJECTIVE

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is a rare hamartomatous lesion of the cerebellar cortex. The pathogenesis of the disease is still poorly understood. Lhermitte-Duclos disease was recently considered to be part of a multiple hamartoma-neoplasia syndrome (Cowden disease). We add two further cases to this rare entity.

PATIENTS

A 24-year old woman presented with occipital headaches, blurred vision, diplopia and ataxia of gait. Physical examination revealed turricephaly. The second patient was a 37-year old woman, who presented with progressive occipital headache with nausea and vomiting. Physical examination revealed congenital facial asymmetry. Computed tomography and NMR-imaging, respectively demonstrated a space occupying mass of a cerebellar hemisphere in both cases.

RESULTS

Suboccipital craniotomy and complete removal of the infratentorial tumour were performed in both patients. Histopathological findings clinched the diagnosis of Lhermitte-Duclos disease. Postoperative course was uneventful in the first and complicated by progressive occlusive hydrocephalus in the second patient, necessitating permanent surgical shunt drainage. Both patients were discharged free of complaints.

CONCLUSIONS

Dysplastic cerebellar gangliocytoma is commonly associated with progressive mass effects in the posterior fossa and typically presents with headaches, cerebellar dysfunction, occlusive hydrocephalus and cranial nerve palsies. The disease usually manifests in young adults, but the age at presentation ranges from birth to the sixth decade. There is no sex predilection. NMR-imaging became a useful clue to the diagnosis within the last decade. Therapy consists of decompression of the posterior fossa by total surgical removal of the tumour mass.

Cowden disease and Lhermitte-Duclos disease: characterization of a new phakomatosis

OBJECTIVE

Lhermitte-Duclos disease, or dysplastic gangliocytoma of the cerebellum, is an unusual hamartomatous lesion that can cause progressive mass effects in the posterior fossa. Cowden disease, or multiple hamartoma-neoplasia syndrome, is a rare autosomal dominant disorder characterized by mucocutaneous hamartomas and high incidences of systemic malignancies. We recently treated a patient with manifestations of both Lhermitte-Duclos disease and Cowden disease, and we were intrigued by the occurrence of these two rare disorders in the same patient. The purpose of the present study was to examine the nature of the association between Lhermitte-Duclos disease and Cowden disease.

METHODS

The records for all patients who had been diagnosed at our institution as having Lhermitte-Duclos disease were reviewed, to determine whether these patients also exhibited manifestations of Cowden disease. Data were obtained from multiple sources, including patient interviews, correspondence with treating physicians, and chart reviews.

RESULTS

During the past 40 years, five patients were diagnosed at Case Western Reserve University as having Lhermitte-Duclos disease. All five patients exhibited manifestations of Cowden disease. Before this review, Cowden disease had not been diagnosed for three of the patients. In our most recent case, the diagnoses of both disorders were established preoperatively. That patient was observed to have a deletion in the critical portion of Exon 5 of the PTEN gene, the gene associated with Cowden disease.

CONCLUSION

Inclusion of Lhermitte-Duclos disease in the Cowden disease spectrum suggests that Cowden disease is a true phakomatosis, with hamartomas arising from cutaneous and neural ectoderm. Recent advances in molecular genetics may help to refine the current descriptive classification of the phakomatoses. The association between Lhermitte-Duclos disease and Cowden disease has been under-recognized and under-reported. Recognition of this association has direct clinical relevance, because diligent long-term follow-up monitoring of individuals with Lhermitte-Duclos disease and Cowden disease may lead to the early detection of malignancy.

Lhermitte-Duclos disease associated with Cowden disease

We encountered a patient with Lhermitte-Duclos disease accompanied by Cowden disease, the second reported in Japan. The histological findings are described in detail. It is important to suspect Cowden disease in patients with Lhermitte-Duclos disease. Although Cowden disease is little known, making the diagnosis is very important, because cancer frequently occurs in the patient's family and genetic counseling is necessary.

Lhermitte-Duclos disease: literature review and novel treatment strategy

BACKGROUND

Lhermitte-Duclos disease (LDD) is a rare pathologic entity involving the cerebellum. The fundamental nature of the entity and its pathogenesis remain unknown, and considerable debate has centered on whether it represents a neoplastic, malformative or hamartomatous lesion. The cell or cells of origin remain incompletely defined. Previous reports of cases in the English literature have dealt predominantly with the clinical and pathological aspects yet few address issues of treatment.

METHODS

A case of Lhermitte-Duclos disease (LDD) in a 54-year-old female leading to local compressive symptoms and obstructive hydrocephalus is presented. A craniectomy, in addition to a C1 laminectomy followed by a decompressive duroplasty (using autologous fascia lata graft) was performed.

RESULTS

The patient clinically improved and follow-up MRI 11 months post-operatively revealed improvement in hydrocephalus.

CONCLUSION

The histological and immunohistochemical features of the lesion are described, emphasizing the role of an abnormal dysplastic granule cell layer. The evidence in favor of each of the major theories of pathogenesis, malformative and neoplastic is discussed. Based on these facts a form of surgical intervention involving decompressive duroplasty is proposed.

Monstrous, crablike hypertrophy of the cerebellar vermis and its relationship with Lhermitte-Duclos disease. Case report

The case of an infant with a peculiar tumorous malformation of the cerebellum is described. The tumor apparently developed as an exophytic, hypertrophic sprout of the inferior vermis. It had a monstrous appearance resembling a crab, with a metameric body and multiple pairs of limbs attached to the folia of both cerebellar hemispheres. Histologically, the lesion was formed by poorly differentiated neuroepithelial cells without any evidence of organization into nuclei, cortex, or fascicles. Clinically, the tumor behaved in indolent manner and did not regrow after subtotal surgical resection. Because of its gross appearance and its biological behavior, this unusual hamartoblastomatous growth is readily distinguished from medulloblastoma. The morphology of the cerebellum in Lhermitte-Duclos disease is reviewed, and a new interpretation of its basic structure is proposed. This and other known types of cerebellar hypertrophy are different from the malformation in the present case.

Vascular contrast enhancement in Lhermitte-Duclos disease: case report

We report a patient with surgically proven Lhermitte-Duclos disease. The radiologic and pathologic features of this cerebellar lesion are reviewed, including the newly reported presence of vascular contrast enhancement within the mass.

Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) and its relation to the multiple hamartoma syndrome (Cowden disease)

The clinical manifestations, surgical treatment and postoperative results of three patients with gangliocytomas of the cerebellum (Lhermitte-Duclos disease) are presented. Particular attention is placed in one of the cases, that of a young woman with a short clinical history of episodic symptoms of intracranial hypertension, dizziness and ataxia, with a concomitant frontal meningioma and in the general context of a multiple hamartoma syndrome (Cowden disease). The possible relationship between both diseases is contemplated, since they can be the extremes of a wide spectrum of a peculiar form of phakomatosis.

Case report: magnetic resonance imaging in Lhermitte-Duclos disease

A case of Lhermitte-Duclos disease is reported. Characterized by architectural disruption of the cerebellar folia with disorganization of the normal three layers, the lesion is easily identified using magnetic resonance imaging.

Lhermitte-Duclos disease and Cowden's syndrome in an adolescent patient. Case report

Recent reports of seven cases of Lhermitte-Duclos disease occurring in adult patients with Cowden's syndrome (multiple hamartoma syndrome) strongly suggest that Lhermitte-Duclos disease is one of the types of neoplasia that characterize this syndrome. A case of Lhermitte-Duclos disease is reported in a 16-year-old girl with craniomegaly, choroidal hamartoma, and conjunctival papilloma of the right eye, and a history of bilateral multinodular adenomatous goiter and cystic hygroma. These findings strongly suggest a diagnosis of Cowden's syndrome. Although the syndrome traditionally has been defined by mucocutaneous criteria, it typically also involves hamartomas and neoplasia of internal organs, most commonly in the thyroid, breast, and female genitourinary tract. Because the mucocutaneous features may develop several decades after birth, the present case both supports the previously reported association between Lhermitte-Duclos disease and Cowden's syndrome and highlights the need for long-term follow-up monitoring of a pediatric patient with Lhermitte-Duclos disease because of the risk of malignancies associated with Cowden's syndrome.

Association of Lhermitte-Duclos and Cowden disease: report of a new case and review of the literature

Lhermitte-Duclos disease is a rare entity, and its pathological features are unique. Pathological findings are characteristic of the disease, with global hypertrophy of the cerebellum, coarse gyri, and the typical "inverted cortex" pattern. Several associated lesions were noted in many patients with Lhermitte-Duclos disease. It is only recently that an association between Lhermitte-Duclos disease and Cowden disease was reported. Cowden disease, or multiple hamartomas syndrome, is a familial disease associating breast cancer, cutaneomucous tricholemmomas, and various other tumoural and dysplasic conditions. A new case of Lhermitte-Duclos disease associated with Cowden disease is reported. A review of the literature found 72 cases of Lhermitte-Duclos disease; 26 had conditions suggesting Cowden disease and seven were definite cases of Cowden disease. The association of Lhermitte-Duclos disease and Cowden disease is probably underestimated. Cowden disease represents a new form of phakomatosis; Lhermitte-Duclos disease may occur as a sporadic disease, or as part of familial Cowden disease. The possibility of preneoplastic states in Cowden syndrome stresses the importance of a thorough screening when Lhermitte-Duclos disease is diagnosed.

Immunohistochemistry and proliferative activity in Lhermitte-Duclos disease

We have evaluated a recurrence of Lhermitte-Duclos disease by immunohistochemistry for Purkinje cell markers and proliferative activity (proliferating cell nuclear antigen), by electron microscopy and for DNA ploidy (image analysis). While most of the abnormal neurons in the lesion appear to be derived from granule cells, several Purkinje cell specific polyclonal and monoclonal antibodies, including L7, PEP 19 and calbindin, labeled a minor subpopulation. Staining with monoclonal antibodies to proliferating cell nuclear antigen and measuring cell DNA index and ploidy with a cell image analyzer revealed no proliferative activity. Electron microscopy findings were similar to those previously reported. In spite of its recurrence, our findings support the notion that Lhermitte-Duclos disease is malformative, not neoplastic, and that the characteristic neurons are derived predominantly but not exclusively from a non-Purkinje cell source, probably the granule cell.

Dysplastic gangliocytoma (Lhermitte-Duclos disease): CT and MR imaging

Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare entity. Usually presenting as a posterior fossa mass, dysplastic gangliocytoma is not a true neoplasm but a hard-to-characterize lesion that may represent an abnormality of cell migration or a phacomatosis. Previous reports of CT findings are rare in the radiologic literature, and high-field (1.5 Tesla) MR images have never been described in the pediatric age group. We present a case of dysplastic gangliocytoma in a one-year-old boy with CT and MR findings.

Recurrent dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) presenting with subarachnoid haemorrhage

A case of dysplastic cerebellar gangliocytoma recurring after 20 years and representing with subarachnoid haemorrhage is described. Evidence in favour of a neoplastic pathogenesis is presented.

Dysplastic gangliocytoma of cerebellum in a newborn. Diagnosis by ultrasonography and MRI

A cerebellar lesion was detected by ultrasonography (US) in a symptomatic newborn. Magnetic Resonance Imaging (MRI) demonstrated this lesion as a gyriform structure. Therefore a rare dysplastic gangliocytoma was suspected, which was compatible with histopathology. Immunohistochemical studies (monoclonal antibody Ki-67) showed signs of progression.

Lhermitte-Duclos disease and Cowden disease: a single phakomatosis

Two unrelated patients with macrocephaly, seizures, and mild cerebellar signs had a dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease). Both also had autosomal dominant Cowden disease as evidenced by facial, oral, and acral papules. In the two families, 9 sibs demonstrated the mucocutaneous lesions, thyroid disease, breast tumors, and ovarian tumors compatible with the diagnosis of Cowden disease. Some of the sibs also showed various degrees of neurological signs such as macrocephaly, mental retardation, seizures, tremor, and dysdiadochokinesia. Magnetic resonance imaging scans of sibs of one family demonstrated megalencephaly and other mild abnormalities. The occurrence of these two rare disorders in single patients is more than a coincidence, and the clinical findings in the combined condition establishes it as a new phakomatosis.

Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum). Report of a case and review of the literature

The authors report the third published case of a Lhermitte-Duclos disease diagnosed preoperatively with the help of MRI, stressing its possible extension beyond the limits of the posterior fossa. The pertinent literature is reviewed concerning the clinical and radiological picture of this disease, as well as the different pathogenic hypothesis.

Pre-operative magnetic resonance imaging in Lhermitte-Duclos disease

A 30-year-old woman presented with a 2.5 year history of symptoms and signs of raised intracranial pressure and unsteadiness of gait. CT showed a non-enhancing hypodense mass lesion in the left cerebellar hemisphere with compression and displacement of the fourth ventricle to the right and hydrocephalus of the third and lateral ventricles. Magnetic resonance imaging showed increased signal intensity in the mass lesion with the preservation of the gyral pattern on T2 weighted sequence. Imaging after gadolinium-DTPA injection showed non-enhancement and slight hypointensity of the lesion on T1 weighted sequence. These MRI findings are helpful in the preoperative diagnosis of Lhermitte-Duclos disease and allow the planning of an appropriate line of treatment for this rare condition.

Recurrent Lhermitte-Duclos disease in a child. Case report

A case of recurrent Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum) in a child is described with a summary of the clinical presentation and associated malformations, and a review of other cases reported in the literature. The histological examination and electron microscopic findings, with special reference to the cytological changes found during evaluation of the recurrence, are presented. Theories regarding the pathogenesis of Lhermitte-Duclos disease are reviewed.

Lhermitte-Duclos disease (dysplastic gangliocytoma): a case report with CT and MRI

A 31 year old female was admitted with a one month history of left foot drop and diplopia. CT of the posterior fossa revealed gross displacement of the 4th ventricle by a large non-enhancing cerebellar mass but gave no indication of its nature. MRI sequences showed two masses within the left cerebellar hemisphere extending into the vermis and demonstrated a very unusual septation within the lesion. In addition both cerebellar tonsils were displaced below the foramen magnum and there was a syrinx extending from C2 to the conus. At operation a demarcated lesion was excised from the apparently normal surrounding cerebellar tissue and proved histologically to be Lhermitte-Duclos disease. We believe that these are the first diagnostic magnetic resonance images of this condition.

Lhermitte-Duclos disease. An immunohistochemical study of the cerebellar cortex

Immunocytochemical studies were carried out on two previously reported autopsy cases of Lhermitte-Duclos disease. The unaffected cerebellar cortex adjacent to the lesions served as control. The findings supported the view, previously expressed by one of the authors, of a heterogeneous neuronal structure of the lesion, consisting of at least two cell types. No further light was thrown on the predominant medium-sized cells, believed to represent hypertrophic internal granular neurons. On the other hand the large cells shared a number of features with Purkinje cells. In particular they were recognized by the pan-T-cell antibody anti-Leu-4, were surrounded by axosomatic synapses visualized by the antisynaptic vesicle glycoprotein antibody SV2, and contained both non-phosphorylated and phosphorylated neurofilament epitopes. It is suggested that these cells represent dysplastic Purkinje cells. The lesion therefore appears to be a complex hamartoma rather than a simple hypertrophy of the internal granular neurons.

Dysplastic disease of the cerebellum of an adult horse

A 4-year-old horse was evaluated at the Colorado State University Veterinary Teaching Hospital for rapidly progressing cerebellar disease. Euthanasia was elected and at postmortem examination a proliferative mass encompassing the right side of the cerebellum was discovered. The lesion was characterized by large, convoluted, vascular folia and absence of the core of central white matter. Histologically, there was a diminution or loss of the internal granule cell layer, cavitation of the central white matter, and absence of Purkinje cells. The molecular layer was thickened with myelinated axons originating from large neurons aberrantly located in this zone. The pathology of this cerebellar mass closely resembles that seen in the cerebellum of humans with Lhermitte-Duclos disease. Mature adults are most commonly affected and clinical signs associated with this disease are often vague. The disease is thought to result from hypertrophy of granule cells possibly due to an early maturation or migration defect. Because of the late age of onset and the rarity of the disorder, its pathogenesis has been difficult to discover. Awareness that other mammalian species may be affected with a similar disorder may lead to an understanding of the causative developmental defect.

Revision of the World Health Organization classification of brain tumors for childhood brain tumors

A classification for childhood brain tumors based upon revision of nomenclature of all brain tumors published by the World Health Organization (WHO) in 1979 is proposed. Applicability of the WHO classification scheme was tested in a combined study of the clinical and pathologic features of approximately 3300 brain tumors in children. It was found to be adequate for many of the neoplasms but unsuitable for a significant proportion, including a number of complex cerebral tumors for which there was no appropriate name. Nomenclature of poorly differentiated or densely cellular neuroepithelial tumors was simplified to reflect the current state of knowledge of neuroembryology and neuro-oncology, although the Committee members recognized that such a proposal would likely perpetuate the long-standing and continuing controversy relative to the nature and origin of these neoplasms.