A novel PTPN11 gene mutation bridges Noonan syndrome, multiple lentigines/LEOPARD syndrome and Noonan-like/multiple giant cell lesion syndrome

Noonan (NS) and multiple lentigines/LEOPARD syndromes (LS) have proved to be associated with distinct PTPN11 mutations. Noonan-like/multiple giant cell lesion syndrome (NLS) is a rare disease, characterised by short stature, facial dysmorphisms, congenital heart defect (CHD) and central giant cell lesions. PTPN11 gene mutations have been reported in a single NLS family and two sporadic patients. Here we report a patient with a complex phenotype progressing throughout the years from NS at birth towards LS and NLS. PTPN11 gene analysis disclosed a novel missense mutation (Ala461Thr) in exon 12, affecting the consensus sequence of the SHP2-active site. This observation joins together NS and LS to NLS into a unique genetic defect, broadening the clinical and molecular spectrum of PTPN11-related disorders.     

A novel PTPN11 mutation in LEOPARD syndrome

PTPN11 gene mutations are common to both patients with Noonan (NS) and LEOPARD syndrome (LS). So far only two recurrent mutations have been identified in LS patients by different research groups, i.e., Tyr279Cys and Thr468Met. In this work we describe the third PTPN11 mutation that has been found in a single LS patient. The mutation (c.1517A>C) substitutes a proline for a glutamine at amino acid 506 (Gln506Pro) in the phosphatase domain (PTP) of the PTPN11 peptide SHP2. This region is a mutation hotspot. Changes at amino acids 501 to 504 cause NS. Gln506Pro is predicted, by modeling analysis, to seriously disrupt the normal contacts between the regulating N-SH2 and the active PTP domains, leading to hyperactivity of the phosphatase. This report demonstrates that rarer mutations other than Tyr279Cys and Thr468Met can be found in LS patients and the need of screening the whole gene in those negative for the commonest mutations.     

Metastatic granular cell tumor to the breast diagnosed by fine needle aspiration cytology: A case report with review of the literature

Granular cell tumors (GCT) are mesenchymal neoplasms of Schwann cell/neural origin. Malignant granular cell tumors (MGCTs) represent <1‐2% of all GCT and defined as tumors demonstrating metastases or destructive local growth. Other clinical parameters suggestive of malignancy include rapid growth, size > 4 cm and necrosis. An apparently inconsistent set of histological features have been described in MGCT. Although the histologic parameters of a GCT are not always predictive of biologic behavior, the presence of atypical features may be indicative of an aggressive clinical behavior (recurrence and metastases). A preoperative estimate of features suggestive of malignancy is important for treatment and prognostication. Diagnosis and prognostication from preoperative fine needle aspiration (FNA) cytology is hampered by the fact that only a few case reports on cytologic features of malignant GCT have been published. We report a case of metastatic MGCT to breast and compare cytologic features to that of primary breast GCT and apocrine/histiocytoid variants of breast carcinoma.     

颗粒细胞瘤15例临床病理分析

目的探讨颗粒细胞瘤的组织起源及临床病理学特征。方法回顾分析15例颗粒细胞瘤的临床资料及组织学形态特征,并采用免疫组化(SP法)观察其免疫表型。结果良性颗粒细胞瘤13例,恶性颗粒细胞瘤2例。男性5例,女性10例,年龄19~69岁,平均年龄41·6岁,2例恶性颗粒细胞瘤年龄分别为67岁和69岁。良性颗粒细胞瘤直径0·4~5·3cm,平均2·3cm,2例恶性颗粒细胞瘤直径分别为6和14cm。均为单发病例,临床上主要表现为真皮、皮下或黏膜下孤立性无痛性结节,分别位于腰部3例、腋下、胸壁各2例,乳腺、上臂、子宫、肛周、声带、食管、结肠、舌部各1例。病理组织学上,良性颗粒细胞瘤的肿瘤细胞通常有比较丰富的嗜酸性颗粒状胞质和小而深染的胞核,而恶性颗粒细胞瘤的肿瘤细胞中可见带有明显核仁的空泡状核,细胞核明显异型及部分细胞呈梭形。免疫组化示神经标记物NSE、S-100蛋白强阳性,表达溶菌酶的标记物CD68也强阳性,而表达平滑肌和横纹肌的标记物SMA、MG均阴性。结论颗粒细胞瘤为来源于雪旺细胞的肿瘤,恶性者少见,大多发生在年龄大的患者,且肿瘤体积比较大。     

LEOPARD syndrome: clinical diagnosis in the first year of life

LEOPARD syndrome (LS) is an autosomal dominant syndrome characterized by multiple lentigines and café-au-lait spots, electrocardiographic-conduction abnormalities, ocular hypertelorism/obstructive cardiomyopathy, pulmonary stenosis, abnormalities of the genitalia in males, retardation of growth, and deafness. LS shares many features with Noonan syndrome (NS), in which lentigines and deafness are usually not present. Molecular studies have shown that LS and NS are allelic disorders, caused by different missense mutations in PTPN11, a gene encoding the protein tyrosine phosphatase SHP-2 located at chromosome 12q22-qter. The clinical diagnosis of LS is generally difficult in the first months of life because the distinctive lentigines are generally not present at birth and develop during childhood. From January 2002 to December 2004, we suspected LS clinically in 10 patients admitted to our genetic counseling services in the first 12 months of life. A PTPN11 gene mutation was detected in 8/10 (80%) patients. In one patient without a PTPN11 mutation a subsequent clinical diagnosis of neurofibromatosis type 1 (NF1) was made, following the evaluation of the mother, who had previously undiagnosed classic NF1. The age of LS patients with PTPN11 mutation ranged between 1 and 11 months (mean age +/- SD 7.5 +/- 3.96 months). Review of the clinical characteristics of patients with LS confirmed by molecular study during the first year of life demonstrates that the diagnosis of LS in the first months of age can be clinically suspected in patients presenting with three main features, that is, characteristic facial features (100%), hypertrophic cardiomyopathy (HCM) (87%), and cafe-au-lait spots (75%). Characteristic facial features can be mild or severe, and consist of hypertelorism, downslanting palpebral fissures, ptosis, and dysmorphic ears. The clinical suspicion of LS may be confirmed by molecular screening for PTPN11 mutations. An early diagnosis of the disease is useful for the prospective care of associated medical problems and for precise genetic counseling.     

Phosphatase-defective LEOPARD syndrome mutations in PTPN11 gene have gain-of-function effects during Drosophila development

Missense mutations in the PTPN11 gene, which encodes the proteintyrosine phosphatase SHP-2, cause clinically similar but distinctivedisorders, LEOPARD (LS) and Noonan (NS) syndromes. The LS isan autosomal dominant disorder with pleomorphic developmentalabnormalities including lentigines, cardiac defects, short statureand deafness. Biochemical analyses indicated that LS allelesengender loss-of-function (LOF) effects, while NS mutationsresult in gain-of-function (GOF). These biochemical findingslead to an enigma that how PTPN11 mutations with opposite effectson function result in disorders that are so similar. To studythe developmental effects of the commonest LS PTPN11 alleles(Y279C and T468M), we generated LS transgenic fruitflies usingcorkscrew (csw), the Drosophila orthologue of PTPN11. Ubiquitousexpression of the LS csw mutant alleles resulted in ectopicwing veins and, for the Y279C allele, rough eyes with increasedR7 photoreceptor numbers. These were GOF phenotypes mediatedby increased RAS/MAPK signaling and requiring the LS mutant’sresidual phosphatase activity. Our findings provide the firstevidence that LS mutant alleles have GOF developmental effectsdespite reduced phosphatase activity, providing a rationalefor how PTPN11 mutations with GOF and LOF produce similar butdistinctive syndromes.     

Implantable cardioverter defibrillator for progressive hypertrophic cardiomyopathy in a patient with LEOPARD syndrome and a novel PTPN11 mutation Gln510His

LEOPARD syndrome (LS), generally caused by heterozygous mutations in the PTPN11 gene, is a rare autosomal-dominant multiple congenital anomaly condition, characterized by skin, facial, and cardiac abnormalities. Prognosis appears to be related to the type of structural, myocardial, and arrhythmogenic cardiac disease, especially hypertrophic cardiomyopathy (HCM). We report on a woman with LS and a novel Gln510His mutation in PTPN11, who had progressive HCM with congestive heart failure and nonsustained ventricular tachycardia, successfully treated with implantable cardioverter defibrillator (ICD). Comparing our patient to the literature suggests that specific mutations at codon 510 in PTPN11 (Gln510Glu, Gln510His, but not Gln510Pro) might be a predictor of fatal cardiac events in LS. Molecular risk stratification and careful evaluations for an indication of ICD implantation are likely to be beneficial in managing patients with LS and HCM.     

Multiple giant cell lesions in patients with Noonan syndrome and cardio-facio-cutaneous syndrome

Noonan syndrome (NS) and cardio-facio-cutaneous syndrome (CFCS) are related developmental disorders caused by mutations in genes encoding various components of the RAS-MAPK signaling cascade. NS is associated with mutations in the genes PTPN11, SOS1, RAF1, or KRAS, whereas CFCS can be caused by mutations in BRAF, MEK1, MEK2, or KRAS. The NS phenotype is rarely accompanied by multiple giant cell lesions (MGCL) of the jaw (Noonan-like/MGCL syndrome (NL/MGCLS)). PTPN11 mutations are the only genetic abnormalities reported so far in some patients with NL/MGCLS and in one individual with LEOPARD syndrome and MGCL. In a cohort of 75 NS patients previously tested negative for mutations in PTPN11 and KRAS, we detected SOS1 mutations in 11 individuals, four of whom had MGCL. To explore further the relevance of aberrant RAS-MAPK signaling in syndromic MGCL, we analyzed the established genes causing CFCS in three subjects with MGCL associated with a phenotype fitting CFCS. Mutations in BRAF or MEK1 were identified in these patients. All mutations detected in these seven patients with syndromic MGCL had previously been described in NS or CFCS without apparent MGCL. This study demonstrates that MGCL may occur in NS and CFCS with various underlying genetic alterations and no obvious genotype-phenotype correlation. This suggests that dysregulation of the RAS-MAPK pathway represents the common and basic molecular event predisposing to giant cell lesion formation in patients with NS and CFCS rather than specific mutation effects.     

Germline PTPN11 missense mutation in a case of Noonan syndrome associated with mediastinal and retroperitoneal neuroblastic tumors

Noonan syndrome (NS) is an autosomal dominant disorder characterized by short stature, typical craniofacial dysmorphism, skeletal anomalies, congenital heart defects, and predisposition to malignant tumors. In approximately 50% of cases, the disease is caused by missense mutations in the PTPN11 gene. To date, solid tumors, and particularly brain tumors and rhabdomyosarcomas, have been documented in patients with NS; however, few cases of neuroblastoma associated with NS have been reported. Here we report an unusual case of neuroblastoma with mediastinal, retroperitoneal, and medullar locations associated in a NS patient carrying a PTPN11 germline missense mutation (p.G60A). This missense mutation occurs within the N-SH2 domain of the PTPN11 gene and has been reported to be associated with acute leukemia in NS patients. The association of this p.G60A PTPN11 mutation with neuroblastoma provides new evidence that gain of function PTPN11 mutations may play an important role in the pathogenesis of solid tumors associated with Noonan syndrome.     

PTPN11 gene mutation associated with abnormal gonadal determination

Germline mutations in the PTPN11 gene have been associated with Noonan syndrome (NS) and LEOPARD syndrome. Both germline and somatic mutations in this gene have been reported in association with malignancies. However, the T507K mutation in the PTPN11 gene, has only been reported in malignancies and in a fetus with hydrops fetalis but not in a live patient with NS. We report the autopsy findings in a fetus with the T507K mutation who presented prenatally with hydrops fetalis, cystic hygroma and 46, XX karyotype. On autopsy, the patient was found to have testes, male external genitalia, but absent Wolffian ducts.     

Somatic aberrations of mismatch repair genes as a cause of microsatellite‐unstable cancers

Lynch syndrome (LS) is caused by germline mutations in mismatch repair (MMR) genes, resulting in microsatellite‐unstable tumours. Approximately 35% of suspected LS (sLS) patients test negative for germline MMR gene mutations, hampering conclusive LS diagnosis. The aim of this study was to investigate somatic MMR gene aberrations in microsatellite‐unstable colorectal and endometrial cancers of sLS patients negative for germline MMR gene mutations. Suspected LS cases were selected from a retrospective Clinical Genetics Department diagnostic cohort and from a prospective multicentre population‐based study on LS in The Netherlands. In total, microsatellite‐unstable tumours of 40 sLS patients (male/female 20/20, median age 57 years) were screened for somatic MMR gene mutations by next‐generation sequencing. In addition, loss of heterozygosity (LOH) of the affected MMR genes in these tumours as well as in 68 LS‐associated tumours and 27 microsatellite‐unstable tumours with MLH1 promoter hypermethylation was studied. Of the sLS cases, 5/40 (13%) tumours had two pathogenic somatic mutations and 16/40 (40%) tumours had a (likely) pathogenic mutation and LOH. Overall, LOH of the affected MMR gene locus was observed in 24/39 (62%) tumours with informative LOH markers. Of the LS cases and the tumours with MLH1 promoter hypermethylation, 39/61 (64%) and 2/21 (10%) tumours, respectively, demonstrated LOH. Half of microsatellite‐unstable tumours of sLS patients without germline MMR gene mutations had two (likely) deleterious somatic MMR gene aberrations, indicating their sporadic origin. Therefore, we advocate adding somatic mutation and LOH analysis of the MMR genes to the molecular diagnostic workflow of LS. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd     

Diverse driving forces underlie the invariant occurrence of the T42A, E139D, I282V and T468M SHP2 amino acid substitutions causing Noonan and LEOPARD syndromes

Missense PTPN11 mutations cause Noonan and LEOPARD syndromes (NS and LS), two developmental disorders with pleiomorphic phenotypes. PTPN11 encodes SHP2, an SH2 domain-containing protein tyrosine phosphatase functioning as a signal transducer. Generally, different substitutions of a particular amino acid residue are observed in these diseases, indicating that the crucial factor is the residue being replaced. For a few codons, only one substitution is observed, suggesting the possibility of specific roles for the residue introduced. We analyzed the biochemical behavior and ligand-binding properties of all possible substitutions arising from single-base changes affecting codons 42, 139, 279, 282 and 468 to investigate the mechanisms underlying the invariant occurrence of the T42A, E139D and I282V substitutions in NS and the Y279C and T468M changes in LS. Our data demonstrate that the isoleucine-to-valine change at codon 282 is the only substitution at that position perturbing the stability of SHP2's closed conformation without impairing catalysis, while the threonine-to-alanine change at codon 42, but not other substitutions of that residue, promotes increased phosphopeptide-binding affinity. The recognition specificity of the C-SH2 domain bearing the E139D substitution differed substantially from its wild-type counterpart acquiring binding properties similar to those observed for the N-SH2 domain, revealing a novel mechanism of SHP2's functional dysregulation. Finally, while functional selection does not seem to occur for the substitutions at codons 279 and 468, we point to deamination of the methylated cytosine at nucleotide 1403 as the driving factor leading to the high prevalence of the T468M change in LS.     

Mutations of the PTPN11 and RAS genes in rhabdomyosarcoma and pediatric hematological malignancies

PTPN11 has been identified as a causative gene in Noonan syndrome (NS), responsible for about 50% of cases of NS. Given the association between NS and an increased risk of some malignancies, notably leukemia and probably some solid tumors including neuroblastoma (NB) and rhabdomyosarcoma (RMS), recent studies have reported that gain-of-function somatic mutations in PTPN11 occur in some hematological malignancies, especially de novo juvenile myelomonocytic leukemia (JMML) and in some solid tumors such as NB, although at a low frequency. In a screen for mutations of PTPN11 in 7 cell lines and 30 fresh tumors of RMS and in 25 cell lines and 40 fresh tumors of NB, we identified a missense mutation (A72T) in an embryonal RMS patient. In the RMS samples, we also detected mutations of NRAS in 1 cell line and 1 patient; both mutations were in embryonal RMSs and had no PTPN11 mutations. No mutations of PTPN11 were detected in NB. In 95 leukemia cell lines and 261 fresh leukemia samples including 22 JMMLs, 9 kinds of missense mutations were detected in 17 leukemia samples, which included 11 (50.0%) mutations in JMML samples and lower frequencies in other hematological malignancies. Furthermore, we identified 4 (18.2%) NRAS mutations and 1 (4.5%) KRAS mutation in 5 JMML samples, 1 of which had a concomitant PTPN11 mutation. Our data suggest that mutations of PTPN11 as well as RAS play a role in the pathogenesis of not only myeloid hematological malignancies but also a subset of RMS malignancies.     

SOS1: a new player in the Noonan-like/multiple giant cell lesion syndrome

Noonan-like/multiple giant cell lesion syndrome is a rare condition with phenotypic overlap with Noonan syndrome (NS) and cherubism. PTPN11 gene mutations were described in several individuals with this phenotype, and it is recently considered as a variant phenotype of NS. Gain-of-function mutations in the SOS1 gene were recently described as the second major cause of NS. Here, we report for the first time the involvement of SOS1 gene in a family with the Noonan-like/multiple giant cell lesion phenotype.     

Cytomorphology and Clinicopathologic Correlation of the Recurrent and Metastatic Adult Granulosa Cell Tumor of the Ovary: A Retrospective Review

Granulosa cell tumors (GCT) of the ovary are low grade tumor with a potential ability of late pelvic recurrences and distant metastases. However, there is sparse literature on the cytopathologic features of metastatic granulosa cell tumors (MGCT). Between 2000 and 2014, eight cases of MGCT were diagnosed by FNA. Clinical, cytologic, and histopathologic features were reviewed. The age ranged from 34 to 84 years. Metastases were found in abdominal wall (4 cases), pelvic mass (1 case), liver (2 cases), and lung (1 case). The time to metastasis ranged from 1 to 14 years. All cases were hypercellular, with both large and small overlapping cell clusters and individual cells. The cytologic features included: naked nuclei (8/8 cases), Call‐Exner bodies (2/8 cases), and prominent metachromatic stroma (3/8 cases). Moderate cytoplasm (4/8 cases) to scant delicate cytoplasm (4/8 cases) was seen. Cytoplasmic vacuoles were also noted (6/8 cases). N/C ratios were high although lower than small round cell tumors like lymphoma. Prominent, central nucleoli were also present (6/8 cases) as well as nuclear grooves (2/8 cases). Cell block was available in 3/8 cases and all were positive for inhibin immunostain. Histologic examination of the metastatic tissue confirmed MGCT. The important cytologic features of GCT like uniformity of tumor cells, nuclear grooves and Call‐Exner bodies are occasionally present in MGCT. Prominent nucleoli and many naked nuclei were frequent. Therefore, the accurate interpretation of cytologic findings of MGCT requires cytohistologic correlation and inhibin positivity to avoid unnecessary surgical interventions for diagnostic purposes. The possibility of late recurrence of GCT should be kept in mind. Diagn. Cytopathol. 2016;44:1058–1063. © 2016 Wiley Periodicals, Inc.     

The Cytology of a Thyroid Granular Cell Tumor

Granular cell tumor (GCT) of the thyroid is rare. Before this report, only four cases of thyroid GCT have been reported, none of which presented a cytopathological examination. In this paper, we report the fine needle aspiration cytology and pathological analysis of a thyroid GCT from a 12-year-old girl who presented with a painless neck mass. The tumor cells were single, in syncytial clusters, or pseudofollicles, contained small round, oval, or spindle nuclei, indistinct nucleoli, and a large amount of grayish, granular fragile cytoplasm. The background contained granular debris and naked nuclei. A differential diagnosis of thyroid GCT with more frequent thyroid lesions containing cytoplasmic granules, including Hurthle cells, macrophages, follicular cells, and cells of black thyroid syndrome, was also performed.     

SOS1 and PTPN11 mutations in five cases of Noonan syndrome with multiple giant cell lesions

We report five cases of multiple giant cell lesions in patients with typical Noonan syndrome. Such association has frequently been referred to as Noonan-like/multiple giant cell (NL/MGCL) syndrome before the molecular definition of Noonan syndrome. Two patients show mutations in PTPN11 (p.Tyr62Asp and p.Asn308Asp) and three in SOS1 (p.Arg552Ser and p.Arg552Thr). The latter are the first SOS1 mutations reported outside PTPN11 in NL/MGCL syndrome. MGCL lesions were observed in jaws (‘cherubism'') and joints (‘pigmented villonodular synovitis''). We show through those patients that both types of MGCL are not PTPN11-specific, but rather represent a low penetrant (or perhaps overlooked) complication of the dysregulated RAS/MAPK signaling pathway. We recommend discarding NL/MGCL syndrome from the nosology, as this presentation is neither gene-nor allele-specific of Noonan syndrome; these patients should be described as Noonan syndrome with MGCL (of the mandible, the long bone…). The term cherubism should be used only when multiple giant cell lesions occur without any other clinical and molecular evidence of Noonan syndrome, with or without mutations of the SH3BP2 gene.     

The STK11/LKB1 Peutz-Jegher gene is not involved in the pathogenesis of sporadic sex cord-stromal tumors, although loss of heterozygosity at 19p13.3 indicates other gene alteration in these tumors

Germ line mutations in the STK11/LKB1 tumor-suppressor gene (chromosome 19p13.3) are responsible for the Peutz-Jeghers syndrome (PJS). PJS patients frequently develop neoplasms of various organs. Ovarian sex cord-stromal tumor (SCST) with annular tubules, which shows a characteristic morphology intermediate between granulosa cell and Sertoli cell tumors, is distinctively associated with PJS. Although somatic mutations of STK11 are reportedly rare in sporadic forms of common cancers linked to PJS, there are no available studies assessing STK11 alterations in larger series of sporadic ovarian tumors with granulosa, Sertoli or combined differentiation. We examined 29 sporadic SCSTs for loss of heterozygosity (LOH) at 19p13.3, mutation, and promoter methylation of STK11. LOH at 19p13.3 was detected in 12 of 29 (41%) SCSTs, with the highest frequency at chromosome marker D19S894, which localizes approximately 3 mb centromeric to STK11, and it was more frequent in granulosa/Sertoli-stromal cell tumors (10 of 19; 52%) than in thecoma-fibroma tumors (2 of 10; 20%). The 2 fibrothecomas harboring LOH contained sex cord elements. None of the LOH-positive SCSTs demonstrated mutations or promoter methylation of STK11. Our results indicate that LOH at 19p13.3 in sporadic SCSTs targets a gene different from STK11, and may play a role in the pathogenesis of sporadic SCSTs, especially in tumors containing sex cord derivatives.     

Mild variable Noonan syndrome in a family with a novel PTPN11 mutation

Noonan syndrome (OMIM 163950) is a common genetic condition with variable clinical expression and genetic heterogeneity. About half of the cases can be accounted to activating mutations in the PTPN11 gene encoding SHP-2. We report on a family with mild, variable expression of Noonan syndrome in five individuals. Clinical manifestations included short stature, craniofacial anomalies and thorax deformity, but none of the affected family members had a heart defect. Sequencing of the entire coding region of PTPN11 revealed a novel mutation c.1226G-->C in exon 11 predicting the amino acid exchange G409A. This mutation is not located in the previously known mutation clusters. Our observation and the recent report of a mutation affecting a neighbouring residue (T411M) in a family with a variable phenotype suggest that mutations in this particular region of SHP-2 may have effects on the protein that differ from those of the classical mutations.