Muscular phenotype description of abnormal THOC2 splicing.

Until recently, the disease known to be associated with THOC2 mutations was Intellectual developmental disorder, X-linked 12 (MIM300957). However, recently, fetal arthrogryposis multiplex congenita has been associated with a specific splice site mutation in the THOC2 gene. We report a family with the same splice site mutation in the THOC2 gene involved in fetal arthrogryposis as well. We provide the first description of the muscular phenotype of this disease which reveals the presence of cytoplasmic bodies. Our findings expand the clinical phenotype of THOC2 gene related defects.

Androgenetic/biparental mosaicism in a diploid mole-like conceptus: report of a case with triple paternal contribution.

Hydatidiform moles (HMs) are divided into two types: partial hydatidiform mole (PHM) which is most often diandric monogynic triploid and complete hydatidiform mole (CHM) which is most often diploid androgenetic. Morphological features and p57 immunostaining are routinely used to distinguish both entities. Genetic analyses are required in challenging cases to determine the parental origin of the genome and ploidy. Some gestations cannot be accurately classified however. We report a case with atypical pathologic and genetic findings that correspond neither to CHM nor to PHM. Two populations of villi with divergent and discordant p57 expression were observed: morphologically normal p57 + villi and molar-like p57 discordant villi with p57 + stromal cells and p57 - cytotrophoblasts. Genotyping of DNA extracted from microdissected villi demonstrated that the conceptus was an androgenetic/biparental mosaic, originating from a zygote with triple paternal contribution, and that only the p57 - cytotrophoblasts were purely androgenetic, increasing the risk of neoplastic transformation.

Severe Antenatal Hypertrophic Cardiomyopathy Secondary to ACAD9-Related Mitochondrial Complex I Deficiency.

Introduction: Antenatal presentation of hypertrophic cardiomyopathy (HCM) is rare. We describe familial recurrence of antenatal HCM associated with intrauterine growth restriction and the diagnostic process undertaken. Methods: Two pregnancies with antenatal HCM were followed up. Biological assessment including metabolic analyses, genetic analyses, and respiratory chain study was performed. We describe the clinical course of these two pregnancies, antenatal manifestations as well as specific histopathological findings, and review the literature. Results: The assessment revealed a deficiency in complex I of the respiratory chain and two likely pathogenic variations in the ACAD9 gene. Discussion and Conclusion: Antenatal HCM is rare and a diagnosis is not always made. In pregnancies presenting with cardiomyopathy and intrauterine growth restriction, ACAD9 deficiency should be considered as one of the potential underlying diagnoses, and ACAD9 molecular testing should be included among other prenatal investigations.

Estrogen Actions in Placental Vascular Morphogenesis and Spiral Artery Remodeling: A Comparative View between Humans and Mice.

Estrogens, mainly 17ß-estradiol (E2), play a critical role in reproductive organogenesis, ovulation, and fertility via estrogen receptors. E2 is also a well-known regulator of utero-placental vascular development and blood-flow dynamics throughout gestation. Mouse and human placentas possess strikingly different morphological configurations that confer important reproductive advantages. However, the functional interplay between fetal and maternal vasculature remains similar in both species. In this review, we briefly describe the structural and functional characteristics, as well as the development, of mouse and human placentas. In addition, we summarize the current knowledge regarding estrogen actions during utero-placental vascular morphogenesis, which includes uterine angiogenesis, the control of trophoblast behavior, spiral artery remodeling, and hemodynamic adaptation throughout pregnancy, in both mice and humans. Finally, the estrogens that are present in abnormal placentation are also mentioned. Overall, this review highlights the importance of the actions of estrogens in the physiology and pathophysiology of placental vascular development.

Overlapping cortical malformations in patients with pathogenic variants in GRIN1 and GRIN2B.

BACKGROUND: Malformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants in GRIN1 or GRIN2B, genes which encode for subunits of the N-methyl-D-aspartate receptor (NMDAR). The aim of this study was to further define the phenotypic spectrum of NMDAR-related MCDs. METHODS: We report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants in GRIN1 are presented. We report the clinical and neuropathological features of one additional individual with homozygous pathogenic variants in GRIN1. RESULTS: Heterozygous variants in GRIN1 and GRIN2B were associated with overlapping severe clinical and imaging features, including global developmental delay, epilepsy, diffuse dysgyria, dysmorphic basal ganglia and hippocampi. Neuropathological examination in two fetuses with heterozygous GRIN1 variants suggests that proliferation as well as radial and tangential neuronal migration are impaired. In addition, we show that neuronal migration is also impaired by homozygous GRIN1 variants in an individual with microcephaly with simplified gyral pattern. CONCLUSION: These findings expand our understanding of the clinical and imaging features of the 'NMDARopathy' spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.

Severe placental lesions due to maternal SARS-CoV-2 infection associated to intrauterine fetal death.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause severe placental lesions leading rapidly to intrauterine fetal death (IUFD). From August 2020 to September 2021, in the pathology department of Toulouse Oncopole, we analyzed 50 placentas from COVID-19-positive unvaccinated mothers. The purpose of our study is to describe the clinicopathological characteristics of these placental damages and to understand the pathophysiology. Ten of them (20%) showed placental lesions with positive immunohistochemistry for SARS-CoV-2 in villous trophoblasts. In five cases (10%), we observed massive placental damage associating trophoblastic necrosis, fibrinous deposits, intervillositis, as well as extensive hemorrhagic changes due to SARS-CoV-2 infection probably responsible of IUFD by functional placental insufficiency. In five other cases, we found similar placental lesions but with a focal distribution that did not lead to IUFD but live birth. These lesions are independent of maternal clinical severity of COVID-19 infection because they occur despite mild maternal symptoms and are therefore difficult to predict. In our cases, they occurred 1-3 weeks after positive SARS-CoV-2 maternal real-time polymerase chain reaction testing and were observed in the 2nd and 3rd trimesters of pregnancies. When these lesions are focal, they do not lead to IUFD and can be involved in intrauterine growth restriction. Our findings, together with recent observations, suggest that future pregnancy guidance should include stricter pandemic precautions such as screening for a wider array of COVID-19 symptoms, enhanced ultrasound monitoring, as well as newborn medical surveillance.

Human cytomegalovirus infection is associated with increased expression of the lissencephaly gene PAFAH1B1 encoding LIS1 in neural stem cells and congenitally infected brains.

Congenital infection of the central nervous system by human cytomegalovirus (HCMV) is a leading cause of permanent sequelae, including mental retardation or neurodevelopmental abnormalities. The most severe complications include smooth brain or polymicrogyria, which are both indicative of abnormal migration of neural cells, although the underlying mechanisms remain to be determined. To gain better insight on the pathogenesis of such sequelae, we assessed the expression levels of a set of neurogenesis-related genes, using HCMV-infected human neural stem cells derived from embryonic stem cells (NSCs). Among the 84 genes tested, we found dramatically increased expression of the gene PAFAH1B1, encoding LIS1 (lissencephaly-1), in HCMV-infected versus uninfected NSCs. Consistent with these findings, western blotting and immunofluorescence analyses confirmed the increased levels of LIS1 in HCMV-infected NSCs at the protein level. We next assessed the migratory abilities of HCMV-infected NSCs and observed that infection strongly impaired the migration of NSCs, without detectable effect on their proliferation. Moreover, we observed increased immunostaining for LIS1 in brains of congenitally infected fetuses, but not in control samples, highlighting the clinical relevance of our findings. Of note, PAFAH1B1 mutations (resulting in either haploinsufficiency or gain of function) are primary causes of hereditary neurodevelopmental diseases. Notably, mutations resulting in PAFAH1B1 haploinsufficiency cause classic lissencephaly. Taken together, our findings suggest that PAFAH1B1 is a critical target of HCMV infection. They also shine a new light on the pathophysiological basis of the neurological outcomes of congenital HCMV infection, by suggesting that defective neural cell migration might contribute to the pathogenesis of the neurodevelopmental sequelae of infection. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Further delineation of the clinical spectrum of KAT6B disorders and allelic series of pathogenic variants.

PURPOSE: Genitopatellar syndrome and Say-Barber-Biesecker-Young-Simpson syndrome are caused by variants in the KAT6B gene and are part of a broad clinical spectrum called KAT6B disorders, whose variable expressivity is increasingly being recognized. METHODS: We herein present the phenotypes of 32 previously unreported individuals with a molecularly confirmed diagnosis of a KAT6B disorder, report 24 new pathogenic KAT6B variants, and review phenotypic information available on all published individuals with this condition. We also suggest a classification of clinical subtypes within the KAT6B disorder spectrum. RESULTS: We demonstrate that cerebral anomalies, optic nerve hypoplasia, neurobehavioral difficulties, and distal limb anomalies other than long thumbs and great toes, such as polydactyly, are more frequently observed than initially reported. Intestinal malrotation and its serious consequences can be present in affected individuals. Additionally, we identified four children with Pierre Robin sequence, four individuals who had increased nuchal translucency/cystic hygroma prenatally, and two fetuses with severe renal anomalies leading to renal failure. We also report an individual in which a pathogenic variant was inherited from a mildly affected parent. CONCLUSION: Our work provides a comprehensive review and expansion of the genotypic and phenotypic spectrum of KAT6B disorders that will assist clinicians in the assessment, counseling, and management of affected individuals.

p57-discordant villi in hydropic products of conception: a clinicopathological study of 70 cases.

p57 immunostaining is performed on hydropic products of conception to diagnose hydatidiform moles (HMs), which can progress to gestational trophoblastic neoplasia. Partial hydatidiform mole (PHM) and hydropic abortion (HA) display positive staining in stromal and cytotrophoblastic cells, whereas complete hydatidiform mole (CHM) is characterized by loss of p57 expression in both cell types. In some cases, an aberrant pattern is observed, called discordant p57 expression, with positive cytotrophoblast staining and negative stromal staining, or vice versa. The aim of this study was to describe the clinical, biological, and pathological characteristics of p57-discordant villi (p57DV) and other associated populations in cases of divergent p57 expression and to compare the evolutions of p57DV-associated and classic CHMs. Seventy cases of p57DV diagnosed by referent pathologists were divided into two groups, G1: p57DV ± non-CHM component (n = 22) and G2: p57DV + CHM component (n = 48). p57DV morphology was similar in the two groups. Observation of more than two populations and hybrid villi on p57 immunostaining were significantly more frequent in G2. The clinical, ultrasound, and biological presentations of p57DV-associated and classic CHMs were similar. The initial pathological diagnosis was more frequently incorrect, missing the CHM component, for the p57DV-associated CHMs. Molecular genotyping was informative in seven cases and identified as androgenetic/biparental mosaicism in four cases. These results show that p57DV are a diagnostic challenge for pathologists and that most are associated with a CHM component. However, the clinical management of p57DV-associated CHMs should be the same as that of classic CHMs.

Regulation of human cerebral cortical development by EXOC7 and EXOC8, components of the exocyst complex, and roles in neural progenitor cell proliferation and survival.

PURPOSE: The exocyst complex is a conserved protein complex that mediates fusion of intracellular vesicles to the plasma membrane and is implicated in processes including cell polarity, cell migration, ciliogenesis, cytokinesis, autophagy, and fusion of secretory vesicles. The essential role of these genes in human genetic disorders, however, is unknown. METHODS: We performed homozygosity mapping and exome sequencing of consanguineous families with recessively inherited brain development disorders. We modeled an EXOC7 splice variant in vitro and examined EXOC7 messenger RNA (mRNA) expression in developing mouse and human cortex. We modeled exoc7 loss-of-function in a zebrafish knockout. RESULTS: We report variants in exocyst complex members, EXOC7 and EXOC8, in a novel disorder of cerebral cortex development. In EXOC7, we identified four independent partial loss-of-function (LOF) variants in a recessively inherited disorder characterized by brain atrophy, seizures, and developmental delay, and in severe cases, microcephaly and infantile death. In EXOC8, we found a homozygous truncating variant in a family with a similar clinical disorder. We modeled exoc7 deficiency in zebrafish and found the absence of exoc7 causes microcephaly. CONCLUSION: Our results highlight the essential role of the exocyst pathway in normal cortical development and how its perturbation causes complex brain disorders.

One year of experience using the Paris System for Reporting Urinary Cytology.

BACKGROUND: The Paris System for Reporting Urinary Cytology (TPS) was published in November 2015. It focuses on the diagnosis of high-grade urothelial carcinoma (HGUC) and provides criteria with which to define the category of atypical urothelial cells (AUC). The objective of the current study was to compare two 1-year consecutive periods before and after use of TPS. METHODS: A total of 1634 and 1814 urine cytology cases, respectively, were analyzed before and after use of TPS. Histological diagnosis within 6 months was available for 330 and 299 cases, respectively. RESULTS: After use of TPS, the authors reported significantly fewer low-grade urothelial neoplasms (0.94% vs 1.84%; P<.05) and more cases that were suspicious for HGUC (2.09% vs 0.73%; P<.01) compared with before use of TPS. For the AUC category, there was no significant change in frequency noted for before versus after TPS (6.12% vs 5.18%), whereas the rate of detection of HGUC on histology significantly increased after TPS when compared with before TPS (49.02% vs 28.17%; P<.02). For the HGUC category, neither the frequency (4.69% vs 4.47%) nor the risk of malignancy (89.39% vs 91.04% with HGUC on histology) were found to be significantly different when comparing before and after use of TPS. CONCLUSIONS: In the authors' practice, TPS helped to better characterize the categories of AUC, low-grade urothelial neoplasm, and suspicious for HGUC, which were associated with a higher risk of HGUC compared with the authors' previous classification. Cancer Cytopathol 2018;126:430-6. © 2018 American Cancer Society.

Mutations in GREB1L Cause Bilateral Kidney Agenesis in Humans and Mice.

Congenital anomalies of the kidney and urinary tract (CAKUT) constitute a major cause of chronic kidney disease in children and 20% of prenatally detected anomalies. CAKUT encompass a spectrum of developmental kidney defects, including renal agenesis, hypoplasia, and cystic and non-cystic dysplasia. More than 50 genes have been reported as mutated in CAKUT-affected case subjects. However, the pathophysiological mechanisms leading to bilateral kidney agenesis (BKA) remain largely elusive. Whole-exome or targeted exome sequencing of 183 unrelated familial and/or severe CAKUT-affected case subjects, including 54 fetuses with BKA, led to the identification of 16 heterozygous variants in GREB1L (growth regulation by estrogen in breast cancer 1-like), a gene reported as a target of retinoic acid signaling. Four loss-of-function and 12 damaging missense variants, 14 being absent from GnomAD, were identified. Twelve of them were present in familial or simplex BKA-affected case subjects. Female BKA-affected fetuses also displayed uterus agenesis. We demonstrated a significant association between GREB1L variants and BKA. By in situ hybridization, we showed expression of Greb1l in the nephrogenic zone in developing mouse kidney. We generated a Greb1l knock-out mouse model by CRISPR-Cas9. Analysis at E13.5 revealed lack of kidneys and genital tract anomalies in male and female Greb1l-/- embryos and a slight decrease in ureteric bud branching in Greb1l+/- embryos. We showed that Greb1l invalidation in mIMCD3 cells affected tubulomorphogenesis in 3D-collagen culture, a phenotype rescued by expression of the wild-type human protein. This demonstrates that GREB1L plays a major role in early metanephros and genital development in mice and humans.

PPARγ Is Activated during Congenital Cytomegalovirus Infection and Inhibits Neuronogenesis from Human Neural Stem Cells.

Congenital infection by human cytomegalovirus (HCMV) is a leading cause of permanent sequelae of the central nervous system, including sensorineural deafness, cerebral palsies or devastating neurodevelopmental abnormalities (0.1% of all births). To gain insight on the impact of HCMV on neuronal development, we used both neural stem cells from human embryonic stem cells (NSC) and brain sections from infected fetuses and investigated the outcomes of infection on Peroxisome Proliferator-Activated Receptor gamma (PPARγ), a transcription factor critical in the developing brain. We observed that HCMV infection dramatically impaired the rate of neuronogenesis and strongly increased PPARγ levels and activity. Consistent with these findings, levels of 9-hydroxyoctadecadienoic acid (9-HODE), a known PPARγ agonist, were significantly increased in infected NSCs. Likewise, exposure of uninfected NSCs to 9-HODE recapitulated the effect of infection on PPARγ activity. It also increased the rate of cells expressing the IE antigen in HCMV-infected NSCs. Further, we demonstrated that (1) pharmacological activation of ectopically expressed PPARγ was sufficient to induce impaired neuronogenesis of uninfected NSCs, (2) treatment of uninfected NSCs with 9-HODE impaired NSC differentiation and (3) treatment of HCMV-infected NSCs with the PPARγ inhibitor T0070907 restored a normal rate of differentiation. The role of PPARγ in the disease phenotype was strongly supported by the immunodetection of nuclear PPARγ in brain germinative zones of congenitally infected fetuses (N = 20), but not in control samples. Altogether, our findings reveal a key role for PPARγ in neurogenesis and in the pathophysiology of HCMV congenital infection. They also pave the way to the identification of PPARγ gene targets in the infected brain.

Severe hydrocephalus caused by diffuse leptomeningeal and neurocutaneous melanocytosis of antenatal onset: a clinical, pathologic, and molecular study of 2 cases.

Diffuse leptomeningeal melanocytosis (DLM) is a rare nevomelanocytic proliferation arising in the meninges. Despite their lack of morphological features of malignancy, these clonal nevomelanocytic cells are capable of extensive invasion and of malignant behavior. When associated with congenital melanocytic nevi, the disorder is named neurocutaneous melanocytosis (NCM). When symptomatic, DLM is usually revealed during childhood, but some cases remain clinically silent. The aim of this study was to analyze melanocytic proliferation in 2 rare and severe cases of isolated DLM and NCM of prenatal onset by neuropathologic and molecular analysis. We performed neuropathologic examination, comparative genomic hybridization arrays, fluorescence in situ hybridization, BRAF and NRAS pyrosequencing in the 2 cases, and next-generation sequencing in the case of isolated DLM. The neuropathologic examination showed diffuse meningeal melanocytic proliferation involving the whole central nervous system with multiple areas of intraneural invasion, associated with large nevi in 1 case. We did not find any chromosomal imbalances. A NRAS(Q61K) mutation was found in the cutaneous and meningeal lesions from the NCM. No mutation was found within a panel of oncogenes including BRAF, NRAS, HRAS, KIT, GNAQ, and GNA11 concerning the isolated DLM. We report 2 exceptional cases of hydrocephalus of prenatal onset related to DLM and NCM. The molecular mechanisms underlying our case of DLM remain unsolved despite the panel of analysis applied.

Improving the cytological diagnosis of intraocular lymphoma from vitreous fluid.

AIMS: To improve the cytological diagnosis of retinal lymphoma on vitreous fluid using improved cell collection and systematic analyses. METHODS AND RESULTS: Since October 2010, we have developed and optimized in our department a method with which to perform the diagnosis of retinal lymphoma. The vitreous sample was collected in a tube containing RPMI-1640 medium, decomplemented fetal bovine serum, and gentamicin. The transport and technical steps were performed at 4°C. Systematically, cytological examination with May-Grünwald-Giemsa staining and immunocytochemistry (mainly anti-CD3, anti-CD20 and anti-CD68 antibodies) were performed on cytospins. Whenever possible, determination of B-cell clonality, flow cytometry and determination of the interleukin (IL)-10/IL-6 ratio were performed. From October 2010 to June 2013, with this optimized protocol, 38 vitreous cytological samples from 32 patients were analysed, and a final diagnosis was possible, avoiding a biopsy, in all cases except one. CONCLUSION: The preservation of vitreous fluid cells on culture medium led to the diagnosis of retinal lymphoma in 10 of 12 cases, and exclusion of this diagnosis in 26 cases. This protocol may be applied even when the delay in shipping from the surgery to the pathology departments exceeds 1 h.

Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly.

Cobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the arachnoid space forms an extracortical layer that produces agyria and/or a "cobblestone" brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits. These include Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN, and FKRP identified these diseases as alpha-dystroglycanopathies. Our exhaustive screening of these six genes, in a cohort of 90 fetal cases, led to the identification of a mutation in only 53% of the families, suggesting that other genes might also be involved. We therefore decided to perform a genome-wide study in two multiplex families. This allowed us to identify two additional genes: TMEM5 and ISPD. Because TMEM has a glycosyltransferase domain and ISPD has an isoprenoid synthase domain characteristic of nucleotide diP-sugar transferases, these two proteins are thought to be involved in the glycosylation of dystroglycan. Further screening of 40 families with cobblestone lissencephaly identified nonsense and frameshift mutations in another four unrelated cases for each gene, increasing the mutational rate to 64% in our cohort. All these cases displayed a severe phenotype of cobblestone lissencephaly A. TMEM5 mutations were frequently associated with gonadal dysgenesis and neural tube defects, and ISPD mutations were frequently associated with brain vascular anomalies.

NEK1 and DYNC2H1 are both involved in short rib polydactyly Majewski type but not in Beemer Langer cases.

BACKGROUND: The lethal short rib polydactyly syndromes (SRP type I-IV) are characterised by notably short ribs, short limbs, polydactyly, multiple anomalies of major organs, and autosomal recessive mode of inheritance. Among them, SRP type II (Majewski; MIM 263520) is characterised by short ovoid tibiae or tibial agenesis and is radiographically closely related to SRP type IV (Beemer-Langer; MIM 269860) which is distinguished by bowed radii and ulnae and relatively well tubulated tibiae. NEK1 mutations have been recently identified in SRP type II. Double heterozygosity for mutations in both NEK1 and DYNC2H1 in one SRP type II case supported possible digenic diallelic inheritance. METHODS: The aim of this study was to screen DYNC2H1 and NEK1 in 13 SRP type II cases and seven SRP type IV cases. It was not possible to screen DYNC2H1 in two patients due to insufficient amount of DNA. RESULTS: The study identified homozygous NEK1 mutations in 5/13 SRP type II and compound heterozygous DYNC2H1 mutations in 4/12 cases. Finally, NEK1 and DYNC2H1 were excluded in 3/12 SRP type II and in all SRP type IV cases. The main difference between the mutation positive SRP type II group and the mutation negative SRP type II group was the presence of holoprosencephaly and polymycrogyria in the mutation negative group. CONCLUSION: This study confirms that NEK1 is one gene causing SRP type II but also reports mutations in DYNC2H1, expanding the phenotypic spectrum of DYNC2H1 mutations. The exclusion of NEK1 and DYNC2H1 in 3/12 SRP type II and in all SRP type IV cases further support genetic heterogeneity.

Cerebrospinal fluid cytologic findings of a pleomorphic xanthoastrocytoma: a case report.

BACKGROUND: Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic neoplasm with a relatively favorable prognosis. Characteristic histologic features include pleomorphic tumor cells and lipidized cells expressing glial fibrillary acidic protein (GFAP), corresponding to a World Health Organization grade 2 tumor. Cytologic features of PXA have been rarely described, only in squash specimens, but only 2 cases are reported in cerebrospinal fluid (CSF). CASE: A 45-year-old woman complained of severe headaches and diplopia. Computed tomography of the central nervous system revealed a supracallous periventricular tumor mass suggestive of either a lymphoma or a metastatic carcinoma. CSF revealed 18 cells/mm3 and contained numerous tumor cells highly pleomorphic in size and shape. Some atypical cells of moderate size were closely packed with well-defined cytoplasmic limits and a vacuolated appearance, suggesting an epithelial proliferation. On immunocytochemistry atypical cells were positive for GFAP, S100 protein and synaptophysin but were negative for pancytokeratins and epithelial membrane antigen. A primitive glial proliferation was found, and paraffin-embedded tumor tissue obtained by biopsy confirmed the diagnosis of anaplastic PXA. CONCLUSION: Observation of PXA in CSF might cause some differential diagnosis problems, especially with a metastatic epithelial malignancy. We present a case of anaplastic PXA with an unusual periventricular location and its cytologic features in CSF.

Melanotic neuroectodermal tumour of infancy: A case report and review of the aetiopathogenic hypotheses

The case of a 2-month-old healthy infant without relevant medical history. The patient was referred due to the aggravation of a swelling occupying the left half of the anterior maxilla. This lesion became visible approximately one month ago; it involved the buccal gingiva and alveolar bone, including the deciduous tooth germs 6.1 and 6.2.The swelling had dimensions of 20 mm x 20 mm. The surgical excision was performed under general anesthesia.The tooth buds of 6.1 and 6.2 were closely related to the tumour and so were removed. The lesion was entirely enucleated. The pathology of the lesion confirmed a melanotic neuroectodermal tumour of infancy. The melanotic neuroectodermal tumour of infancy (MNTI) has been described as a rare benign pigmented painless swelling that usually occurs in the anterior region of the maxilla and in the incisor region. The histological examination showed small basophilic cells, many containing melanin pigmentation within the cytoplasm, with a second population of larger cubical cells with abundant cytoplasm, arranged in alveolar or adenoid clusters. According to Krompecher this tumour derives from epithelial nests evolved at the time of embryonic fusion of the facial processes. It has also been suggested that the tumour arises from the retinal anlage by a pinching-off process of neuroepithelium during the formation of embryonic eye. More recently, the presence of high levels of vanillylmandelic acid suggest a neural origin of the tumour (AU)

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