Extradural ependymal tumor with myxopapillary and ependymoblastic differentiation in a case of Schinzel-Giedion syndrome

Putative Roles of SETBP1 Dosage on the SET Oncogene to Affect Brain Development

Mutations in SET BINDING PROTEIN 1 (SETBP1) cause two different clinically distinguishable diseases called Schinzel–Giedion syndrome (SGS) or SETBP1 deficiency syndrome (SDD). Both disorders are disorders of protein dosage, where SGS is caused by decreased rate of protein breakdown due to mutations in a proteosome targeting domain, and SDD is caused by heterozygous loss-of-function mutations leading to haploinsufficiency. While phenotypes of affected individuals support a role for SETBP1 in brain development, little is known about the mechanisms that might underlie this. The binding partner which gave SETBP1 its name is SET and there is extensive literature on this important oncogene in non-neural tissues. Here we describe different molecular complexes in which SET is involved as well as the role of these complexes in brain development. Based on this information, we postulate how SETBP1 protein dosage might influence these SET-containing molecular pathways and affect brain development. We examine the roles of SET and SETBP1 in acetylation inhibition, phosphatase activity, DNA repair, and cell cycle control. This work provides testable hypotheses for how altered SETBP1 protein dosage affects brain development.

Pediatric spinal intramedullary anaplastic myxopapillary ependymoma: a case report

A 6-year-old girl presented with a 1-week history of progressive upper and lower extremity weakness and bilateral upper extremity dysesthesia. Imaging demonstrated a 4.7 × 1.2-cm enhancing intramedullary lesion in the cervical spine from level C2 to C5 with associated cystic components and syringomyelia. The patient underwent a C2-C5 laminoplasty, with gross total resection of the intramedullary lesion. Histological analysis showed small to medium-sized epithelioid cells, with predominantly a solid architecture focally infiltrating into the adjacent spinal cord tissue. Focal papillary differentiation was present along with peri-vascular pseudorosettes, mucin microcysts, and globules of dense collagen. Focal anaplasia was noted with mitosis (5/10 HPF), focal necrosis, and elevated Ki67 10-15%. These findings were consistent with a myxopapillary ependymoma with anaplastic features. CSF cytology was negative for tumor cells. MYCN amplification was not present. She was treated with targeted proton-beam radiation therapy. This is the fourth case of an intramedullary anaplastic myxopapillary ependymoma to date, and the first case in the cervical spine reported in the literature.

Anaplastic myxopapillary ependymoma: A case report and review of literature

BACKGROUND

Myxopapillary ependymoma (MPE) is a pathological grade I tumor that arises in the filum terminale. MPE with anaplastic features is extremely rare, and only 5 cases have shown malignancy at the time of recurrence.

CASE SUMMARY

The patient (a 46-year-old woman) had undergone a MPE operation 30 years ago. After subtotal resection of the tumor located in L4-S1, it had a solid component that extended to the adjacent subcutaneous region. Histologically, the tumor consisted of a typical MPE with anaplastic features. The anaplastic areas of the tumor showed hypercellularity, a rapid mitotic rate, vascular proliferation, and connective tissue proliferation. Pleomorphic cells and atypical mitotic figures were occasionally observed. The MIB-1 index in this area was 12.3%. The immunohistochemical study showed immunoreactivity for vimentin, glial fibrillary acidic protein and S100. The morphological pattern and immunohistochemical profile were consistent with anaplastic MPE. The patient tolerated surgery well without new neurological deficits. She underwent local irradiation for the residual tumor and rehabilitation.

CONCLUSION

Although extremely rare, anaplastic MPE occurs in both pediatric and adult patients, similar to other ependymomas. At a minimum, close monitoring is recommended, given concerns about aggressive biological potential. In the future, further study is needed to determine the WHO classification criteria and genetic indicators of tumor progression. The possibility of malignant transformation of MPE should be taken into account, and patients with MPE should be treated with care and follow-up.

Myxopapillary Ependymoma with Anaplastic Features: A Case Series and Review of the Literature

BACKGROUND

Myxopapillary ependymomas (MPEs) with anaplastic features are rarely reported, with only 21 cases identified to date, and long-term recurrence is rarely presented. A case series is presented to expand understanding of this disease by describing 3 unique cases, including 2 that arose from MPE after a prolonged clinical course.

METHODS

A literature review was performed, and 3 cases of MPE with anaplastic features from our institution were included.

RESULTS

Patient 1 was a 13-year-old boy who presented with an avidly enhancing intradural lumbar mass. On gross total resection, the tumor was found to be a solid mass with areas of myxopapillary architecture and MIB-1 (Ki-67) index of 12%. Patient 2 was a woman who initially presented at age 22 with a lumbosacral tumor that was treated with surgery and radiation. A recurrent tumor was resected at age 24. At age 50, the patient presented with a large heterogeneous exophytic mass in the sacrum extending into the presacral space and Ki-67 index of 8%. This was treated with complete resection. Patient 3 was a man who initially presented at age 35 with a lower thoracic, upper lumbar mass at L2 extending into the sacrum. Following resection and radiation, a metastatic focus followed an indolent course until causing pain at the age of 48. Ki-67 index was 16%.

CONCLUSIONS

The presented cases of MPE with anaplastic features make a total of 24 cases on record in the medical literature and demonstrate 2 examples of late recurrence.

Pediatric Myxopapillary Ependymomas: A Clinicopathologic Evaluation

Myxopapillary ependymomas (MPEs) have an indolent clinical course, corresponding to World Health Organization Grade I. A total of 13 pediatric MPEs have been reported in the literature with "anaplastic features," including elevated proliferative activity (≥5 mitoses/10 high-power fields), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. A retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996 and 2018 at Mayo Clinic was performed. Totally, 8 pediatric MPEs (6 male; age: 7.52 to 16.88 y) were identified. Totally, 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross total; 1 subtotal). Totally, 5 cases harbored ≥5 mitoses/10 high-power fields (range: 5 to 9), 3 of which showed necrosis (2 with disseminated disease). Postsurgery, 2 patients received radiation; one with disseminated disease and another with increased mitotic activity/necrosis; neither has recurred (follow-up: 1.18 and 3.19 y). In all, 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of nonresected metastatic foci (2.6 and 26.8 mo), received radiation therapy, and remain progression free (3.01 and 9.34 y). All patients are alive (median follow-up 1.31 y, range: 0.66 to 11.75). Among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with an aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies.

Pediatric Extraspinal Sacrococcygeal Ependymoma: Report of Two Cases and Literature Review

Primary central nervous system (CNS) tumors represent the most common solid tumors in childhood. Ependymomas arise from ependymal cells lining the wall of ventricles or central canal of spinal cord and their occurrence outside the CNS is extremely rare, published in the literature as case reports or small case series. We present two cases of extra-CNS myxopapillary ependymomas treated at our institution in the past three years; both cases originate in the sacrococcygeal region and were initially misdiagnosed as epidermoid cyst and germ cell tumor, respectively. The first case, which arose in a 9-year-old girl, was treated with a surgical excision in two stages, due to the non-radical manner of the first operation; no recurrence was observed after two years of follow-up. The other case was a 12-year-old boy who was treated with a complete resection and showed no evidence of recurrence at one-year follow-up. In this paper, we report our experience in treating an extremely rare disease that lacks a standardized approach to diagnosis, treatment and follow-up; in addition, we perform a literature review of the past 35 years.

Anaplastic myxopapillary ependymoma of the sacrum: A case report

Background

Myxopapillary ependymoma (MPE) with anaplastic features is extremely rare. There are very few such case reports in the medical literature.

Case Description

A 23-year-old female presented with lower back pain, and both urinary and fecal dysfunction. The patient underwent gross total surgical excision of the MR documented expansile intrasacral tumor. The histology was compatible with a MPE containing anaplastic features.

Conclusion

The medical literature contains a few comparable cases of subcutaneous sacrococcygeal MPE with anaplastic components. Here, however, we have a young female with an anaplastic intrasacral MPE treated with gross total surgical excision.

Anaplastic Transformation in Myxopapillary Ependymoma: A Report of 2 Cases and Review of the Literature

Myxopapillary ependymoma (MPE) is a relatively common neoplasm arising primarily in the filum terminale/lumbosacral region of the spinal cord. It is designated as a grade I tumor in the most recent WHO Classification of Tumours of the CNS, although aggressive clinical behavior can be observed, especially in cases arising in an extradural location. Anaplastic transformation in MPE is exceedingly rare with <20 examples reported in the English literature, and consensus on diagnostic features and definitive grading remain to be determined. Here, we present 2 cases of recurrent MPE with anaplastic features, both of which had histology consistent with conventional MPE as well as areas with significant atypia, frequent mitotic figures, elevated Ki-67 proliferation indices (>10%-50%), necrosis, and focal vascular proliferation. Targeted next-generation sequencing panels revealed no definitive pathogenic mutations or fusion proteins in either case. Copy number profiling, methylation profiling, and t-Distributed Stochastic Neighbor Embedding were performed to investigate the molecular characteristics of these tumors. To the best of our knowledge, these are the first reported cases of MPE with anaplastic features with methylation profiling data. In addition, we review the literature and discuss common histologic and molecular findings associated with anaplastic features in MPE.

Extra-axial sacral soft tissue giant cell ependymoma affecting a child: Case report and review of the literature

An otherwise healthy eight-year-old girl presented with a mass in the soft tissue of the sacral region. The lesion was diagnosed as a vascular malformation on imaging studies, for which percutaneous sclerotherapy was attempted. The mass continued to grow and a complete resection was performed after four years. The pathological diagnosis was giant cell ependymoma (GCE). GCE is a term used to describe a rare histologic variant of ependymoma characterized by malignancy-like morphologic phenotype and indolent behavior. To the best of our knowledge, this is the first case of extra-axial soft tissue sacral GCE reported in a child.

Subcutaneous sacrococcygeal myxopapillary ependymoma misdiagnosed as pilonidal disease

Ependymomas are neoplasms which arise from the radial glial cells, which many recent studies have proposed are neural stem cells. Extracranial ependymomas are rare. We present the case report and supporting multimedia of a 37-year-old man who presented with a painless intergluteal swelling which was diagnosed clinically as a pilonidal cyst. However, on excision, he was found to have a subcutaneous sacrococcygeal myxopapillary ependymoma based on histological findings. His management and follow-up are presented and discussed. Given the rare nature of this condition, there is a lack of published guidelines on management and follow-up protocols. Supporting evidence is limited to sporadic case reports. This case highlights the diagnostic challenges and management strategies adopted supported by the best available evidence.

Clinicopathologic features of anaplastic myxopapillary ependymomas

Myxopapillary ependymomas (MPE) are considered benign (World Health Organization (WHO) grade I) neoplasms with favorable prognosis. However, malignant behavior occurs in a small subset. To our knowledge, only five anaplastic MPEs have been reported without consensus on diagnostic criteria. We retrieved 14 anaplastic MPEs from the pathology archives of six institutions. Each tumor included at least two of the following features: ≥5 mitoses per 10 high power fields, Ki-67 labeling index (LI) ≥10%, microvascular proliferation (MVP) and spontaneous necrosis. These features were typically encountered in the foci of hypercellularity and reduced mucin. There were eight male and six female patients (age range 6-57 years, median = 16.5). Ten tumors displayed anaplasia at initial resection, and 4 were anaplastic at a second surgery for recurrence (ranging from 9 months to 14 years following initial resection). The Ki-67 LI ranged between 8% and 40% in the anaplastic foci and <3% in the foci of classic MPE. There was documented cerebrospinal fluid (CSF) dissemination in seven cases, recurrence following an anaplastic diagnosis in three cases and bone or soft tissue invasion in two cases. One patient suffered lung metastases. Two cases evaluated by targeted next-generation sequencing and one evaluated by fluorescence in situ hybridization (FISH) showed nonspecific chromosomal gains. We conclude that although rare, anaplastic MPE occurs in both pediatric and adult patients, similar to other ependymomas. At a minimum, closer follow-up is recommended, given the concern for aggressive biologic potential. Further study is needed to determine WHO grading criteria and genetic indicators of tumor progression.

Myxopapillary ependymoma with anaplastic features: A case report with review of the literature

Background:

Myxopapillary ependymoma (MPE) with anaplastic features is extremely rare, with only three case reports in the literature.

Case Description:

We report the case of a MPE with anaplastic features in a 24-year-old female who presented with a dominant lumbar mass along with intracranial and sacral metastases. Upon gross total resection of the dominant tumor located at L2-L3, it appeared to arise from the filum terminale, and had a solid component in addition to soft or necrotic areas. Histologically, the tumor was composed of the two classic components of MPE: (1) low-grade ependymal cells surrounding blood vessels, producing the papillary appearance and (2) perivascular myxoid material between blood vessels and ependymal cells, creating the myxopapillary appearance. The high-grade anaplastic component showed hypercellularity, brisk mitotic rate, and vascular proliferation, with frequent pleomorphic cells and atypical mitotic figures. It was positive for vimentin and glial fibrillary acidic protein (GFAP); negative for epithelial membrane antigen (EMA), CAM5.2, creatine kinase 7 (CK7), CK20; and the MIB-1 index (Ki-67) was 8–38%. Ten months after initial resection, follow-up magnetic resonance imaging revealed new lesions in (1) the hypothalamus, (2) the left pons, and (3) the left medial temporal lobe, which were treated with radiosurgery. Eight months later (18 months from initial surgery), the patient underwent thoracic laminectomy for a large leptomeningeal metastasis at T6 and T8.

Conclusion:

The present case of MPE with anaplastic features is the fourth case on record in the medical literature.

Pediatric extraspinal sacrococcygeal ependymoma (ESE): an Italian AIEOP experience of six cases and literature review

BACKGROUND

Primary pediatric extraspinal sacrococcygeal ependymoma (ESE) is a very rare disease, poorly described in literature, whose diagnostic, therapeutic, and follow-up approach is still controversial.

METHODS

We describe six cases of pediatric ESE treated at Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers in Italy since 1983, with a review of the literature.

RESULTS

All six patients had primary sacrococcygeal disease (two presacral and four subcutaneous) with median age of 10 years. Three patients were males, and two of them are metastatic at diagnosis; 3/6 had myxopapillary ependymoma grade I and 3/6 had classic ependymoma grade II. Five patients underwent surgical resection with complete removal only in one case with coccygectomy. Adjuvant chemoradiotherapy was administered to one metastatic patient obtaining a complete remission. Two patients relapsed at 3 and 8 years from diagnosis: they were treated with salvage chemotherapy (high-dose sequential chemotherapy with myeloablative regimen in one case), surgery, and radiotherapy achieving complete remission (CR). All six patients are in complete continuous remission (CCR) at a median follow-up of 12.8 years.

CONCLUSIONS

Pediatric patients with this peculiar disease need to be referred to specialized pediatric cancer centers that can provide multidisciplinary treatment after a centralized pathology review. Our experience highlights the role of chemotherapy and radiotherapy in adjuvant and relapse setting. The final prognosis is relatively optimistic, but with a careful follow-up due to the high risk of recurrence.

Unusual paediatric spinal myxopapillary ependymomas: Unique molecular entities or pathological variations on a theme?

Ependymomas are the commonest type of spinal glioma which represent a group of relatively benign tumours. Myxopapillary ependymoma (MPE) is a common variant found within the distal spinal cord around the conus. These two entities are clearly differentiated on the basis of their characteristic histological and molecular features. Rare variants of MPE's are described in the literature to have the propensity to metastasise and grow in extraspinal locations despite appearing histologically identical to their more benign relatives. Here, we describe two unusual cases of MPE and utilise DNA methylation analyses to compare their molecular signatures with known molecular subtypes of ependymoma in an attempt to distinguish whether these tumours represent a unique subset of disease.

Schinzel-Giedion Syndrome with Congenital Megacalycosis in a Turkish Patient: Report of SETBP1 Mutation and Literature Review of the Clinical Features

Schinzel-Giedion syndrome (SGS) is a rare autosomal dominant disorder that results in facial dysmorphism, multiple congenital anomalies, and an increased risk of malignancy. Recently, using exome sequencing, de novo heterozygous mutations in the SETBP1 gene have been identified in patients with SGS. Most affected individuals do not survive after childhood because of the severity of this disorder. Here, we report SETBP1 mutation confirmed by molecular analysis in a case of SGS with congenital megacalycosis.

SETBP1 dysregulation in congenital disorders and myeloid neoplasms

Myeloid malignancies are characterized by an extreme molecular heterogeneity, and many efforts have been made in the past decades to clarify the mechanisms underlying their pathogenesis.

In this scenario SET binding protein 1 (SETBP1) has attracted a lot of interest as a new oncogene and potential marker, in addition to its involvement in the Schinzel-Giedon syndrome (SGS). Our review starts with the analysis of the structural characteristics of SETBP1, and extends to its corresponding physiological and pathological functions. Next, we describe the prevalence of SETBP1 mutations in congenital diseases and in hematologic malignancies, exploring how its alterations might contribute to tumor development and provoke clinical effects. Finally, we consider to understand how SETBP1 activation could be exploited in molecular medicine to enhance the cure rate.

Lymph node metastasis of presacral ependymoblastoma in a young child

Ependymoblastoma presenting outside the brain is rare in children. The overwhelming majority of presacral ependymal tumors are of the benign myxpapillary type. We present a case of ependymoblastoma in the presacral region of a four-year old child. The patient presented with a presacral mass and ipsilateral inguinal lymph node metastasis. Both masses revealed histologic and immunophenotypic features of ependymoblastoma associated with myxoid areas and high Ki-67 proliferation index. The masses were excised and the patient remained well for a year after diagnosis with no other therapy. This report emphasizes ependymoblastoma as rare entity in the differential diagnosis of presacral tumors in children and, up to our knowledge, the first report of inguinal lymph node metastasis of ependymoblastoma.

Refractory sacrococcygeal germ cell tumor in Schinzel-Giedion syndrome

We describe a boy with Schinzel-Giedion syndrome who developed refractory sacrococcygeal germ cell tumor with elements of embryonal carcinoma and immature teratoma. He developed local recurrence soon after tumor resection. The tumor was highly resistant to platinum-based combination chemotherapy, local irradiation, and salvage chemotherapy. Frequent infections resulted in a delay in treatment, although apparent fragility had not been observed clinically. He died from tumor progression at 32 months of age. Intensification of chemotherapy does not seem to be feasible for tumors in patients with Schinzel-Giedion syndrome.

Schinzel-Giedion syndrome in two Brazilian patients: Report of a novel mutation in SETBP1 and literature review of the clinical features

Schinzel-Giedion syndrome is a rare autosomal dominant disorder comprising postnatal growth failure, profound developmental delay, seizures, facial dysmorphisms, genitourinary, skeletal, neurological, and cardiac defects. It was recently revealed that Schinzel-Giedion syndrome is caused by de novo mutations in SETBP1, but there are few reports of this syndrome with molecular confirmation. We describe two unrelated Brazilian patients with Schinzel-Giedion syndrome, one of them carrying a novel mutation. We also present a review of clinical manifestations of the syndrome, comparing our cases to patients reported in literature emphasizing the importance of the facial gestalt associated with neurological involvement for diagnostic suspicion of this syndrome.

[Schinzel-Giedion syndrome: a new mutation in SETBP1]

Schinzel-Giedion syndrome (SGS) (#MIM 269150) is a rare genetic disorder characterized by very marked craniofacial dysmorphism, multiple congenital anomalies and severe intellectual disability. Most affected patients die in early childhood. SETBP1 was identified as the causative gene, but a limited number of patients with molecular confirmation have been reported to date. The case is reported of a 4 and a half year-old male patient, affected by SGS. SETBP1 sequencing analysis revealed the presence of a non-previously described mutation: c.2608G>T (p.Gly870Cys). The clinical features and differential diagnosis of this rare condition are reviewed. Dysmorphic features are strongly suggestive of SGS. Its clinical recognition is essential to enable an early diagnosis, a proper follow-up, and to provide the family with genetic counseling. To date, this is the seventeenth SGS patient published with SETBP1 mutation, and the first in Spain, helping to widen clinical and molecular knowledge of the disease.

Sacrococcygeal myxopapillary ependymoma with anaplastic ependymoma component in an infant

Sacrococcygeal location of myxopapillary ependymoma (MPE) is uncommon. Local recurrence and metastases are on record inspite of its benign characteristics. We report a rare case of sacrococcygeal MPE in an 11-month-old female child who showed typical myxopapillary ependymal histology along with anaplastic ependymal component. Ki-67 labeling index in the myxopapillary component was 4-5% and in the anaplastic component was 70%. Six weeks after gross total resection of the tumor, the child presented with local recurrence and metastasis in the right inguinal lymph nodes and was treated with chemotherapy. The present case of sacrococcygeal MPE with anaplastic ependymoma component is the second case on record in the medical literature, and the first case without any syndromic features. Metastasis in this case can be explained because of the anaplastic component, with mitotic count of 5-6/high power field and high Ki-67 labeling index.

Distinct neurological features in a patient with Schinzel-Giedion syndrome caused by a recurrent SETBP1 mutation

INTRODUCTION

Schinzel-Giedion syndrome (SGS) is a rare multiple congenital malformation syndrome defined by characteristic facial features, profound developmental delay, severe growth failure, and multiple congenital anomalies. Most individuals affected by SGS die in early childhood mainly because of progressive neurodegeneration and respiratory failure. The causative gene of SGS, SETBP1, was identified, but there are few reports of SGS with molecular confirmation worldwide.

PATIENT AND METHOD

In this study, we present a 10-month-old boy presenting with SGS complicated by epilepsy and profound developmental delay.

RESULTS

Typical facial features, multiple anomalies, and associated neurological findings suggested a clinical diagnosis of SGS. Unusually in our patient, generalized tonic seizure occurred and has been controlled well by combined antiepileptic therapy during 7 months of follow-up. Electroencephalography findings were compatible with partial seizures, and ventriculomegaly, thinning of the corpus callosum, and delayed myelination were identified on brain MR images. SETBP1 mutational analysis revealed the presence of a recurrent mutation, p.Gly870Ser. Thus, the diagnosis of our patient was molecularly confirmed as SGS.

CONCLUSIONS

Although this syndrome is extremely rare, it is important to consider SGS in the differential diagnosis of infantile-onset epilepsy with progressive neurodevelopmental retardation, especially in patients with multiple anomalies and facial dysmorphism.

Cobblestone lissencephaly in Schinzel-Giedion syndrome

The brain of a 5-year-old boy with Schinzel-Giedion syndrome displayed a cobblestone appearance of orbital and lateral aspects of frontal lobes due to widespread glioneuronal meningeal heterotopia. Meningeal heterotopia consisted of scattered neurons, neurofilament positive axons, and myelinated fibers accompanied by striking astrocytic gliosis. The underlying cortex showed gaps in the pial basal lamina, distorted neuronal layering, and focal polymicrogyria. The number of capillaries appeared increased throughout the brain. Mild hydrocephalus was associated with a slight atrophy of corpus callosum as well as villous hyperplasia and marked stromal degeneration of the choroid plexus. Our findings suggest that Schinzel-Giedion syndrome may represent One more entity within enlarging spectrum of lissencephalic cortical dysplasia syndromes.

Schinzel-Giedion syndrome: a further cause of early myoclonic encephalopathy and vacuolating myelinopathy

Here, we report a male child with Schinzel-Giedion syndrome associated with intramyelinic edema detected on brain magnetic resonance imaging (MRI) and persistent suppression-burst pattern on electroencephalography (EEG) with erratic myoclonus of the extremities and face. Similar to nonketotic hyperglycinemia, Schinzel-Giedion syndrome may be recognized as another causative genetic disease of early myoclonic encephalopathy and vacuolating myelinopathy.

Scoliosis in a case of Schinzel-Giedion syndrome

Schinzel-Giedion syndrome (SGS) is a rare disorder characterized by midface retraction, hypertrichosis, and multiple skeletal anomalies with severe mental retardation. Various skeletal manifestations of the disease have been previously described. We present the first case of SGS developing scoliosis. The patient presented with scoliosis at the age of 8 years which rapidly progressed to severe thoraco-lumbar scoliosis. Survival beyond 2 years is rare in this syndrome. The objective of this report is to describe the possibility of development of scoliosis in SGS due to the neuromuscular nature of the syndrome, especially in long survivors.

Schinzel-Giedion syndrome: report of splenopancreatic fusion and proposed diagnostic criteria

We report on the 46th patient with Schinzel-Giedion syndrome (SGS) and the first observation of splenopancreatic fusion in this syndrome. In the antenatal period, a male fetus was found to have bilateral hydronephrosis. Postnatally, in keeping with a diagnosis of SGS, there were large fontanelles, ocular hypertelorism, a wide, broad forehead, midface retraction, a short, upturned nose, macroglossia, and a short neck. Other anomalies included cardiac defects, widened and dense long bone cortices, cerebral ventriculomegaly, and abnormal fundi. Splenopancreatic fusion, usually encountered in trisomy 13, was found on autopsy. Schinzel-Giedion syndrome is likely a monogenic condition for which neither the heritability pattern nor pathogenesis has yet been determined. A clinical diagnosis may be made by identifying the facial phenotype, including prominent forehead, midface retraction, and short, upturned nose, plus one of either of the two other major distinguishing features: typical skeletal abnormalities or hydronephrosis. Typical skeletal anomalies include a sclerotic skull base, wide supraoccipital-exoccipital synchondrosis, increased cortical density or thickness, and broad ribs. Other highly supportive features include neuroepithelial tumors (found in 17%), hypertrichosis, and brain abnormalities. Severe developmental delay and poor survival are constant features in reported patients.