DICER1 mutations in childhood cystic nephroma and its relationship to DICER1-renal sarcoma

Poorly differentiated thyroid carcinoma of childhood and adolescence: a distinct entity characterized by DICER1 mutations

Poorly differentiated thyroid carcinomas (PDTC) in young individuals are rare and their clinical and histopathologic features, genetic mechanisms, and outcomes remain largely unknown. Here, we report a detailed characterization of a series of six PDTC in patients ≤21 years old defined by Turin diagnostic criteria studied for mutations and gene fusions characteristic of thyroid cancer using targeted next-generation sequencing (NGS) and whole-exome sequencing (WES). All tumors had solid, insular, or trabecular growth pattern and high mitotic rate, and five out of six tumors showed tumor necrosis. Targeted NGS assay identified somatic mutations in the DICER1 gene in five of six (83%) tumors, all of which were "hotspot" mutations encoding the metal-ion binding sites of the RNase IIIb domain of DICER1. WES was performed in five cases which confirmed all hotspot mutations and detected two tumors with additional inactivating DICER1 alterations. Of these two, one was a germline pathogenic DICER1 variant and the other had loss of heterozygosity for DICER1. No other mutations or gene fusions characteristic of adult well-differentiated thyroid cancer and PDTC (BRAF, RAS, TERT, RET/PTC, and other) were detected. On follow-up, available for five patients, three patients died of disease 8-24 months after diagnosis, whereas two were alive with no disease. The results of our study demonstrate that childhood- and adolescent-onset PDTC are genetically distinct from adult-onset PDTC in that they are strongly associated with DICER1 mutations and may herald DICER1 syndrome in a minority. As such, all young persons with PDTC may benefit from genetic counseling. Furthermore, their clinically aggressive behavior contrasts sharply with the indolent nature of the great majority of thyroid tumors with DICER1 mutations reported to date.

Defining an embryonal rhabdomyosarcoma endotype

Rhabdomyosarcoma (RMS) is the most common childhood soft-tissue sarcoma. The largest subtype of RMS is embryonal rhabdomyosarcoma (ERMS) and accounts for 53% of all RMS. ERMS typically occurs in the head and neck region, bladder, or reproductive organs and portends a promising prognosis when localized; however, when metastatic the 5-yr overall survival rate is ∼43%. The genomic landscape of ERMS demonstrates a range of putative driver mutations, and thus the recognition of the pathological mechanisms driving tumor maintenance should be critical for identifying effective targeted treatments at the level of the individual patients. Here, we report genomic, phenotypic, and bioinformatic analyses for a case of a 3-yr-old male who presented with bladder ERMS. Additionally, we use an unsupervised agglomerative clustering analysis of RNA and whole-exome sequencing data across ERMS and undifferentiated pleomorphic sarcoma (UPS) tumor samples to determine several major endotypes inferring potential targeted treatments for a spectrum of pediatric ERMS patient cases.

DICER1 screening in 15 paediatric paratesticular sarcomas unveils an unusual DICER1-associated sarcoma

Individuals with DICER1 syndrome, a genetic disorder caused by pathogenic germline variants in DICER1, are at increased risk of developing a wide array of predominantly childhood onset conditions, including genitourinary sarcomas. However, data on DICER1 involvement in paratesticular sarcomas have not been published. Herein, we analyse a series of 15 paediatric paratesticular sarcomas and describe in detail the case of a male infant with a paratesticular myxoid tumour, considered to be a low‐grade sarcoma, who also manifested a cystic nephroma, a classic DICER1 syndrome phenotype. He harboured a pathogenic germline DICER1 variant and different somatic hot‐spot mutations in each tumour. The paratesticular tumour showed strong and diffuse expression for WT1 and CD10, an unusual immunophenotype in paediatric sarcomas, but typical of tumours of Müllerian origin. The tumour was postulated to arise from the appendix testis, a Müllerian remnant located in the paratestis. Such an origin would be analogous to other DICER1‐associated non‐epithelial gynaecological tumours, thought to arise from Müllerian derivatives. These findings point towards a key role of DICER1 in Müllerian‐derived structures. Supporting this hypothesis is the fact that the other paratesticular sarcomas from the series were either negative or focally positive for WT1 and for CD10, and none had any DICER1 mutations. In summary, we present the first case of a paratesticular sarcoma associated with DICER1 syndrome, emphasising that paratesticular tumours with an unusual histological appearance may suggest an underlying DICER1 mutation, especially in the presence of a personal or family history of DICER1‐associated disease. In this context, DICER1 mutation testing could lead to changes in clinical care including implementation of cancer care surveillance strategies.

An organoid biobank for childhood kidney cancers that captures disease and tissue heterogeneity

Kidney tumours are among the most common solid tumours in children, comprising distinct subtypes differing in many aspects, including cell-of-origin, genetics, and pathology. Pre-clinical cell models capturing the disease heterogeneity are currently lacking. Here, we describe the first paediatric cancer organoid biobank. It contains tumour and matching normal kidney organoids from over 50 children with different subtypes of kidney cancer, including Wilms tumours, malignant rhabdoid tumours, renal cell carcinomas, and congenital mesoblastic nephromas. Paediatric kidney tumour organoids retain key properties of native tumours, useful for revealing patient-specific drug sensitivities. Using single cell RNA-sequencing and high resolution 3D imaging, we further demonstrate that organoid cultures derived from Wilms tumours consist of multiple different cell types, including epithelial, stromal and blastemal-like cells. Our organoid biobank captures the heterogeneity of paediatric kidney tumours, providing a representative collection of well-characterised models for basic cancer research, drug-screening and personalised medicine.

Pre-clinical cell culture models capturing the heterogeneity of childhood kidney tumours are limited. Here, the authors establish and characterise an organoid biobank of tumour and matched normal organoid cultures from over 50 children with different subtypes of kidney cancer.

Complexity in regulating microRNA biogenesis in cancer

The discovery of microRNA (miRNA) significantly extends our knowledge on gene regulation and noncoding gene functions. MiRNAs are important post-transcriptional regulators involve in a wide range of biological functions and diseases, including cancer. MiRNAs are produced by a unique biogenesis pathway involving the two-step sequential nuclear and cytoplasmic RNase-dependent processing at post-transcriptional level. However, a specific (set) of miRNA(s) is (are) synthesized under certain circumstance or developmental/pathological stage to fine-tune the gene expression profile. In this minireview, we will discuss the mechanism of miRNA biogenesis in cancer, mainly focusing on how Drosha and Dicer, two critical molecules controlling miRNA biogenesis, are modulated and which factor contributes to the specificity of selected miRNA maturation.

Impact statement

The canonical maturation pathway of miRNAs is highly conserved, indicating the crucial roles of these mini-regulators in most cellular processes. Dysregulation of specific miRNAs or imbalance of miRNA abundance has been observed in cancers. Accumulating evidence has shown that the interplay between miRNA processing factors and regulatory proteins previously known as key players in cancer malignancy regulates the biogenesis of miRNAs, expression of target genes, and eventually the alteration of cellular phenotypes. This minireview summarizes the current findings in the modulation of miRNA biogenesis in cancer to advance the understanding of how noncoding RNA contributes to cancer development and malignancy.

Rare Germline DICER1 Variants in Pediatric Patients With Cushing's Disease: What Is Their Role?

Context: The DICER1 syndrome is a multiple neoplasia disorder caused by germline mutations in the DICER1 gene. In DICER1 patients, aggressive congenital pituitary tumors lead to neonatal Cushing's disease (CD). The role of DICER1 in other corticotropinomas, however, remains unknown. Objective: To perform a comprehensive screening for DICER1 variants in a large cohort of CD patients, and to analyze their possible contribution to the phenotype. Design, setting, patients, and interventions: We included 192 CD cases: ten young-onset (age <30 years at diagnosis) patients were studied using a next generation sequencing panel, and 182 patients (170 pediatric and 12 adults) were screened via whole-exome sequencing. In seven cases, tumor samples were analyzed by Sanger sequencing. Results: Rare germline DICER1 variants were found in seven pediatric patients with no other known disease-associated germline defects or somatic DICER1 second hits. By immunohistochemistry, DICER1 showed nuclear localization in 5/6 patients. Variant transmission from one of the parents was confirmed in 5/7 cases. One patient had a multinodular goiter; another had a family history of melanoma; no other patients had a history of neoplasms. Conclusions: Our findings suggest that DICER1 gene variants may contribute to the pathogenesis of non-syndromic corticotropinomas. Clarifying whether DICER1 loss-of-function is disease-causative or a mere disease-modifier in this setting, requires further studies. Clinical trial registration: ClinicalTrials.gov: NCT00001595.

[DICER1 constitutional pathogenic variant syndrome: Where are we in 2019?]

Inactivating germline pathogenic variants of the DICER1 gene are responsible for a spectrum of rare diseases, which expanded a lot in recent years. The constitution of an U.S. registry with these patients and their families as well as the registration of patients in European databases of rare tumors helped to better identify diseases encountered in this syndrome but also to study its pathophysiology (major role in miRNA maturation and recently discovered functions, e.g. in genome integrity maintenance). Most encountered disorders are pediatric malignancies, mainly the pulmonary pneumoblastoma and Sertoli-Leydig tumours. However, benign pathologies such as thyroid goiters, cystic nephromas or pulmonary cystic lesions are also frequently reported. Homogeneous guidelines regimens written by the European groups working on very rare pediatric tumors are proposed but it is important to underscore that they rely on rare scientific data; therefore overall consensus remains precarious. The genetic counseling to families is still difficult due to the large observed spectrum of tumors and the incomplete penetrance. In this article, the authors update current knowledge on the DICER1 syndrome.

Imaging of DICER1 syndrome

DICER1 syndrome is a highly pleiotropic tumor predisposition syndrome that has been increasingly recognized in the last 10 years. Diseases in the syndrome result from mutations in both copies of the gene DICER1, a highly conserved gene that is critically implicated in micro-ribonucleic acid (miRNA) biogenesis and hence modulation of messenger RNAs. In general, susceptible individuals carry an inherited germline mutation that disables one copy of DICER1; within tumors, a very characteristic second mutation alters function of the other gene copy. About 20 hamartomatous, hyperplastic or neoplastic conditions comprise DICER1 syndrome. Most are not life-threatening, but some are aggressive malignancies. There are many unaffected carriers because penetrance is generally low; however, clinically occult thyroid nodules and lung cysts are frequent. Rare diseases of early childhood were the first recognized conditions in DICER1 syndrome, while other conditions affect adolescents and adults. The hallmarks of DICER1 syndrome are certain rare tumors including pleuropulmonary blastoma; cystic nephroma; ovarian Sertoli-Leydig cell tumor; sarcomas of the cervix, kidneys and cerebrum; pituitary blastoma; ciliary body medulloepithelioma; and nasal chondromesenchymal hamartoma. Radiologists are often the first practitioners to observe these diverse manifestations and play a primary role in recognizing DICER1 syndrome.

RNA-induced initiation of transcriptional silencing (RITS) complex structure and function

Heterochromatic regions of the genome are epigenetically regulated to maintain a heritable '"silent state"'. In fission yeast and other organisms, epigenetic silencing is guided by nascent transcripts, which are targeted by the RNA interference pathway. The key effector complex of the RNA interference pathway consists of small interfering RNA molecules (siRNAs) associated with Argonaute, assembled into the RNA-induced transcriptional silencing (RITS) complex. This review focuses on our current understanding of how RITS promotes heterochromatin formation, and in particular on the role of Argonaute-containing complexes in many other functions such as quelling, release of RNA polymerases, cellular quiescence and genome defense.

Structural renal abnormalities in the DICER1 syndrome: a family-based cohort study

BACKGROUND

The DICER1 syndrome is a tumor-predisposition disorder caused by germline pathogenic variation in DICER1 and is associated with cystic nephroma and other renal neoplasms. Dicer1 mouse and rare human DICER1 syndrome case reports describe structural kidney and collecting system anomalies. We investigated renal function and the frequency of structural abnormalities of the kidney and collecting system in individuals with germline loss-of-function variants in DICER1.

METHODS

In this family-based cohort study, prospectively ascertained germline DICER1-mutation carriers (DICER1-carriers) and unaffected family controls were evaluated at the National Institutes of Health Clinical Center with renal ultrasound and comprehensive laboratory testing. Two radiologists reviewed the imaging studies from all participants for structural abnormalities, cysts, and tumors.

RESULTS

Eighty-nine DICER1-carriers and 61 family controls were studied. Renal cysts were detected in 1/33 DICER1-carrier children without history of cystic nephroma. Similar proportions of adult DICER1-carriers (8/48; 17%) and controls (11/50; 22%) had ultrasound-detected renal cysts (P = 0.504). 8/89 (9%) DICER1-carriers harbored ultrasound-detected structural abnormalities of varying severity within the collecting system or kidney, nephrolithiasis, or nephrocalcinosis. None of the family controls (0/61) had similar findings on ultrasound (P = 0.02). No meaningful differences in renal laboratory values between DICER1-carriers and unaffected family controls were observed.

CONCLUSIONS

Our report is the first to systematically characterize renal function and anatomy in a large prospective cohort of DICER1-carriers and DICER1-negative family controls. DICER1-carriers may be at increased risk of structural anomalies of the kidney or collecting system. The role for DICER1 in renal morphogenesis merits additional investigation.

Adult Renal Neoplasms: Cytology, Immunohistochemistry, and Cytogenetic Characteristics

Tissue sampling of renal masses is traditionally performed using percutaneous sonographic or CT guidance core biopsy (CB) with or without touch preparation cytology and/or fine-needle aspiration cytology (FNAC). The combined used of CB and FNAC is expanding in clinical practice, especially in small renal masses and plays a pivotal role in therapeutic decision making. Grouping the renal neoplasms in differential diagnostic groups helps in choosing specific immunohistochemical markers and reaching an accurate diagnosis.

Cystic nephroma: A case report in adult patients

Cystic nephroma is an unusual, cystic neoplasm of the kidney and is usually benign. There are two peaks in the incidence of the tumor, with a bimodal distribution presenting in children younger than two years old and in adults. These benign lesions are usually seen in childhood, whose clinical presentation is nonspecific with symptoms such as flank pain, hematuria and urinary tract infection. We aim to report treatment, and follow-up of a 48-year-old female patient with cystic nephroma for whom we performed open partial nephrectomy. As a surgical treatment radical or partial nephrectomy is applied according to the size and position of the masses. Long-term follow-up is recommended to rule out local recurrence or metastasis.

DICER1 Syndrome: DICER1 Mutations in Rare Cancers

DICER1 syndrome is a rare genetic disorder that predisposes individuals to multiple cancer types. Through mutations of the gene encoding the endoribonuclease, Dicer, DICER1 syndrome disrupts the biogenesis and processing of miRNAs with subsequent disruption in control of gene expression. Since the first description of DICER1 syndrome, case reports have documented novel germline mutations of the DICER1 gene in patients with cancers as well as second site mutations that alter the function of the Dicer protein expressed. Here, we present a review of mutations in the DICER1 gene, the respective protein sequence changes, and clinical manifestations of DICER1 syndrome. Directions for future research are discussed.

Undifferentiated Sarcomas in Children Harbor Clinically Relevant Oncogenic Fusions and Gene Copy-Number Alterations: A Report from the Children's Oncology Group

Purpose: A comprehensive analysis of the genomics of undifferentiated sarcomas (UDS) is lacking. We analyzed copy-number alterations and fusion status in patients with UDS prospectively treated on Children's Oncology Group protocol ARST0332.Experimental Design: Copy-number alterations were assessed by OncoScan FFPE Express on 32 UDS. Whole-exome and transcriptome libraries from eight tumors with sufficient archived material were sequenced on HiSeq (2 × 100 bp). Targeted RNA-sequencing using Archer chemistry was performed on two additional cases.Results: Five-year overall survival for patients with UDS was 83% (95% CI, 69%-97%) with risk-adapted therapy (surgery, chemotherapy, and radiotherapy). Both focal and arm-level copy-number alterations were common including gain of 1q (8/32, 25%) and loss of 1p (7/32, 22%), both of which occurred more often in clinically defined high-risk tumors. Tumors with both loss of 1p and gain of 1q carried an especially poor prognosis with a 5-year event-free survival of 20%. GISTIC analysis identified recurrent amplification of FGF1 on 5q31.3 (q = 0.03) and loss of CDKN2A and CDKN2B on 9p21.3 (q = 0.07). Known oncogenic fusions were identified in eight of 10 cases analyzed by next-generation sequencing.Conclusions: Pediatric UDS generally has a good outcome with risk-adapted therapy. A high-risk subset of patients whose tumors have copy-number loss of 1p and gain of 1q was identified with only 20% survival. Oncogenic fusions are common in UDS, and next-generation sequencing should be considered for children with UDS to refine the diagnosis and identify potentially targetable drivers. Clin Cancer Res; 24(16); 3888-97. ©2018 AACR.

Uncommon hereditary gynaecological tumour syndromes: pathological features in tumours that may predict risk for a germline mutation

The most common hereditary gynaecological tumour syndromes are hereditary breast and ovarian cancer syndrome and Lynch syndrome. However, pathologists also may encounter gynaecological tumours in women with rare hereditary syndromes. Many of these tumours exhibit distinctive gross and microscopic features that are associated with a risk for an inherited gene mutation. The sensitivity and specificity of these tumour pathology features for predicting an inherited mutation vary depending on the syndrome. By recognising these tumour features, pathologists may potentially contribute to the diagnosis of an unsuspected syndrome by recommending referral of the patient for formal risk assessment by genetic counselling. Patients additionally benefit from diagnosis of an inherited syndrome because many also carry a lifetime risk for developing primary malignancies outside of the gynaecological tract. Early diagnosis of an inherited syndrome permits early screening, detection, and management of additional malignancies associated with the syndrome. This review highlights these rare syndromes and their tumour pathology, including Peutz-Jeghers syndrome (gastric type mucinous carcinoma of the cervix; ovarian sex cord tumour with annular tubules); hereditary leiomyoma renal cell carcinoma syndrome (uterine leiomyoma); tuberous sclerosis complex (uterine PEComa; uterine lymphangioleiomyomatosis); DICER1 syndrome (ovarian Sertoli-Leydig cell tumour; cervical embryonal rhabdomyosarcoma); rhabdoid tumour predisposition syndrome 2 (small cell carcinoma of the ovary, hypercalcaemic type); Cowden syndrome (endometrial endometrioid adenocarcinoma); naevoid basal cell carcinoma syndrome (ovarian fibroma); and Von Hippel-Lindau syndrome (clear cell papillary cystadenoma of the broad ligament).

DICER1 and Associated Conditions: Identification of At-risk Individuals and Recommended Surveillance Strategies

Pathogenic germline DICER1 variants cause a hereditary cancer predisposition syndrome with a variety of manifestations. In addition to conferring increased cancer risks for pleuropulmonary blastoma (PPB) and ovarian sex cord-stromal tumors, particularly Sertoli-Leydig cell tumor, individuals with pathogenic germline DICER1 variants may also develop lung cysts, cystic nephroma, renal sarcoma and Wilms tumor, nodular hyperplasia of the thyroid, nasal chondromesenchymal hamartoma, ciliary body medulloepithelioma, genitourinary embryonal rhabdomyosarcoma, and brain tumors including pineoblastoma and pituitary blastoma. In May 2016, the International PPB Registry convened the inaugural International DICER1 Symposium to develop consensus testing and surveillance and treatment recommendations. Attendees from North America, Europe, and Russia provided expert representation from the disciplines of pediatric oncology, endocrinology, genetics, genetic counseling, radiology, pediatric surgery, pathology, and clinical research. Recommendations are provided for genetic testing; prenatal management; and surveillance for DICER1-associated pulmonary, renal, gynecologic, thyroid, ophthalmologic, otolaryngologic, and central nervous system tumors and gastrointestinal polyps. Risk for most DICER1-associated neoplasms is highest in early childhood and decreases in adulthood. Individual and caregiver education and judicious imaging-based surveillance are the primary recommended approaches. These testing and surveillance recommendations reflect a consensus of expert opinion and current literature. As DICER1 research expands, guidelines for screening and treatment will continue to be updated. Clin Cancer Res; 24(10); 2251-61. ©2018 AACR.

DICER1 syndrome: Approach to testing and management at a large pediatric tertiary care center

BACKGROUND

To expand the current knowledge of DICER1 syndrome and to propose criteria for genetic testing based on experience at a pediatric tertiary care center.

PROCEDURE

This study involved a retrospective chart review of the 78 patients (47 probands and 31 family members) seen in the Cancer Genetics Program at The Hospital for Sick Children (SickKids) who were offered genetic testing for DICER1.

RESULTS

Of 47 probands offered genetic testing for DICER1, 46 pursued testing: 11 (23.9%) carried a pathogenic variant and one proband (2.1%) carried a missense variant of uncertain significance with evidence for pathogenicity. Thirty-one family members of variant-positive probands were offered testing: eight of the 25 who agreed to testing carried their familial variant (32.0%). Overall, 20 patients were identified to have a variant in DICER1 (eight males, 12 females). Of these, 13 (65.0%) presented with clinical manifestations associated with the syndrome. The most common lesions were pleuropulmonary blastoma (PPB) (five of 20 patients, 25.0%) and pineoblastoma (three of 20 patients, 15.0%). The average age at which individuals were diagnosed with a primary neoplasm was 5.2 years (range 0.8-20 years, median 3.0). Surveillance at our institution, with a median follow-up time of 23 months, has identified PPB in two asymptomatic individuals. These lesions were identified at early stages, thus potentially reducing treatment-related morbidity and mortality.

CONCLUSION

This study further delineates the DICER1 syndrome phenotype and demonstrates the feasibility of a DICER1 syndrome surveillance protocol for the early detection of tumors.

Anaplastic sarcomas of the kidney are characterized by DICER1 mutations

Anaplastic sarcoma of the kidney is a rare tumor (≤25 reported cases) characterized by the presence of cysts, and solid areas composed of bundles of undifferentiated spindle cells, showing marked cellular anaplasia (usually accompanied by TP53 overexpression). These tumors often feature prominent areas of cartilage or chondroid material. Germline mutations in DICER1, encoding the microRNA (miRNA) processor DICER1, cause an eponymous syndrome. Recent reports suggest that anaplastic sarcoma of the kidney should be included in DICER1 syndrome as germline DICER1 mutations are associated with the occurrence of such tumors. Therefore, we sought to determine the following: (1) what proportion of anaplastic sarcoma of the kidney have DICER1 mutations; (2) whether the identified mutations affect both alleles of DICER1 (ie, are biallelic); (3) whether somatic missense mutations in the DICER1 RNase IIIb domain impact miRNA generation; and (4) whether TP53 alteration always occurs in these tumors. DICER1 mutations were evaluated by Sanger sequencing and next-generation sequencing in nine tumor/normal pairs. Impact of DICER1 mutations on miRNA generation was evaluated via an in vitro DICER1 cleavage assay. TP53 status was assessed by immunohistochemistry and next-generation sequencing. Eight of the nine cases had at least one RNase IIIb DICER1 mutation that impacted the generation of miRNAs. There were six tumors with truncating DICER1 mutations and in four of them, the mutation found in the tumor was also detected in adjacent normal tissue, and therefore was likely to be either mosaic or germline in origin. Analysis of mutation phase revealed that two of three tumors had biallelic DICER1 mutations. Six of nine anaplastic sarcomas of the kidney had aberrant TP53 immunohistochemisty with damaging TP53 mutations identified in three cases. Taken together, these data suggest that the great majority of anaplastic sarcomas of the kidney have DICER1 mutations and confirm that these tumors are part of the DICER1 syndrome.

The prevalence of DICER1 pathogenic variation in population databases

The DICER1 syndrome is associated with a variety of rare benign and malignant tumors, including pleuropulmonary blastoma (PPB), cystic nephroma (CN) and Sertoli-Leydig cell tumor (SLCT). The prevalence and penetrance of pathogenic DICER1 variation in the general population is unknown. We examined three publicly-available germline whole exome sequence datasets: Exome Aggregation Consortium (ExAC), 1,000 Genomes (1,000 G) and the Exome Sequencing Project (ESP). To avoid over-estimation of pathogenic DICER1 variation from cancer-associated exomes, we excluded The Cancer Genome Atlas (TCGA) variants from ExAC. All datasets were annotated with snpEff and ANNOVAR and variants were classified into four categories: likely benign (LB), unknown significance (VUS), likely pathogenic (LP), or pathogenic (P). The prevalence of DICER1 P/LP variants was 1:870 to 1:2,529 in ExAC-nonTCGA (53,105 exomes) estimated by metaSVM and REVEL/CADD, respectively. A more stringent prevalence calculation considering only loss-of-function and previously-published pathogenic variants detected in ExAC-nonTCGA, yielded a prevalence of 1:10,600. Despite the rarity of most DICER1 syndrome tumors, pathogenic DICER1 variation is more common than expected. If confirmed, these findings may inform future sequencing-based newborn screening programs for PPB, CN and SLCT, in which early detection improves prognosis.

Hereditary Renal Cystic Disorders: Imaging of the Kidneys and Beyond

The purpose of this article is to review the hereditary renal cystic diseases that can manifest in children and adults, with specific attention to pathogenesis and imaging features. Various common and uncommon hereditary renal cystic diseases are reviewed in terms of their underlying etiology, including the involved genetic mutations and the affected proteins and cellular structures. Focus is placed on the morphologic findings in each condition and the features that distinguish one disorder from another. The two most common categories of hereditary renal cystic disease are (a) the ciliopathic disorders, which are related to mutations affecting the primary cilia (called "ciliopathies"), and (b) the phakomatoses. Autosomal dominant polycystic kidney disease, autosomal recessive polycystic kidney disease, and the "medullary cystic disease complex" are all ciliopathies but have different phenotypes. Tuberous sclerosis complex and the associated "contiguous gene syndrome," as well as von Hippel-Lindau syndrome, are phakomatoses that can manifest with cystic renal lesions but have uniquely different extrarenal manifestations. Finally, DICER1 mutations can manifest with renal cystic lesions (typically, cystic nephromas) in patients predisposed to other malignancies in the chest, ovaries, and thyroid. Although some overlap exists in the appearance of the renal cysts associated with each of these diseases, there are clear morphologic differences (eg, cyst size, location, and complexity) that are emphasized in this review. To improve patient outcomes, it is important for the radiologist to recognize the various hereditary renal cystic diseases so that a correct diagnosis is assigned and so that the patient is adequately evaluated and followed up. ^©RSNA, 2017.

Role of Dicer1 in thyroid cell proliferation and differentiation

DICER1 plays a central role in the biogenesis of microRNAs and it is important for normal development. Altered microRNA expression and DICER1 dysregulation have been described in several types of tumors, including thyroid carcinomas. Recently, our group identified a new somatic mutation (c.5438A>G; E1813G) within DICER1 gene of an unknown function. Herein, we show that DICER1 is overexpressed, at mRNA level, in a significant-relative number of papillary (70%) and anaplastic (42%) thyroid carcinoma samples, whereas is drastically downregulated in all the analyzed human thyroid carcinoma cell lines (TPC-1, BCPAP, FRO and 8505c) in comparison with normal thyroid tissue samples. Conversely, DICER1 is downregulated, at protein level, in PTC in comparison with normal thyroid tissues. Our data also reveals that DICER1 overexpression positively regulates thyroid cell proliferation, whereas its silencing impairs thyroid cell differentiation. The expression of DICER1 gene mutation (c.5438A>G; E1813G) negatively affects the microRNA machinery and cell proliferation as well as upregulates DICER1 protein levels of thyroid cells but has no impact on thyroid differentiation. In conclusion, DICER1 protein is downregulated in papillary thyroid carcinomas and affects thyroid proliferation and differentiation, while DICER1 gene mutation (c.5438A>G; E1813G) compromises the DICER1 wild-type-mediated microRNA processing and cell proliferation.

DICER1-related Sertoli-Leydig cell tumor and gynandroblastoma: Clinical and genetic findings from the International Ovarian and Testicular Stromal Tumor Registry

BACKGROUND

Ovarian sex cord-stromal tumors (OSCST) include juvenile granulosa cell tumors (JGCT), Sertoli-Leydig cell tumor (SLCT) and gynandroblastoma (GAB) among others. These ovarian sex cord-stromal tumors as well as other tumors including pleuropulmonary blastoma (PPB) may be associated with DICER1 mutations. We sought to describe the clinical and genetic findings from the first 107 individuals enrolled in the International Ovarian and Testicular Stromal Tumor Registry.

METHODS

Medical and family history were obtained for individuals consecutively enrolled in the International Ovarian and Testicular Stromal Tumor Registry. Pathology was centrally reviewed. DICER1 sequencing was performed on blood and tumor tissue.

RESULTS

Of the 107 participants, 49 had SLCT, 25 had JGCT and 5 had GAB. Nearly all (36/37) SLCTs and 4/4 GAB tested had a DICER1 mutation in an RNase IIIb domain hotspot; approximately half of these individuals had a predisposing germline DICER1 mutation. Metachronous SLCTs were seen in 3 individuals with germline DICER1 mutations. Other DICER1-associated conditions were seen in 19% of patients with SLCT or GAB. Three children of women with SLCT were diagnosed with PPB based on genetic testing and clinical screening during the course of this study. All were diagnosed with PPB in its earliest and most curable form (Type I), were treated with surgery alone, and are alive without evidence of disease.

CONCLUSIONS

Recognition of the distinct genetic basis for a group of these tumors improves precise classification in difficult cases and promotes mutation-based screening and early detection.

Ovarian Sex Cord-Stromal Tumors

Ovarian sex cord-stromal tumors are clinically significant heterogeneous tumors that include several pathologic types. These tumors are often found in adolescents and young adults and can present with hormonal manifestations as well as signs and symptoms of a pelvic mass. Serum tumor markers may assist in preoperative diagnosis and surveillance. Several subtypes are associated with genetic predisposition, including those observed in patients with Peutz-Jegher syndrome. Recent studies have elucidated the relationship between Sertoli-Leydig cell tumors and DICER1 mutations. When classified as International Federation of Gynecology and Obstetrics stage Ia, most subtypes may be treated with surgery alone. Higher stage or recurrent tumors have variable prognoses that range from a usually rapid course in poorly differentiated Sertoli-Leydig cell tumor to an often prolonged course in adult granulosa cell tumors. New understanding of the molecular pathogenesis of these tumors may pave the way for novel therapeutics.

DICER1 mutation and tumors associated with a familial tumor predisposition syndrome: practical considerations

The familial tumor predisposition syndrome known as DICER1-pleuropulmonary blastoma (PPB) or DICER1 tumor predisposition syndrome was first described in 2009, and it involves an increased risk in the occurrence of various tumors, like cystic nephroma and PPB. Here is presented a girl with a cystic nephroma and two cystic lung lesions who was diagnosed years later with the DICER1 gene mutation. This mutation was also found in one of her parents. Thus, the screening for the DICER1 gene mutation may be important in children with certain/multiple tumors and their families.

Pediatric imaging in DICER1 syndrome

BACKGROUND

DICER1 syndrome, arising from a mutation in the DICER1 gene mapped to chromosome 14q32, is associated with an increased risk of a range of benign and malignant neoplasms.

OBJECTIVE

To determine the spectrum of abnormalities and imaging characteristics in patients with DICER1 syndrome at a tertiary pediatric hospital.

MATERIALS AND METHODS

This retrospective analysis evaluated imaging in patients ≤18 years with DICER1 germline variants between January 2004 and July 2016. An imaging database search including keywords pleuropulmonary blastoma, cystic nephroma, pineoblastoma, embryonal rhabdomyosarcoma, ovarian sex cord-stromal tumor, ovarian Sertoli-Leydig cell tumor and DICER1 syndrome, was cross-referenced against the institutional Cancer Genetics Program database, excluding patients with negative/unknown DICER1 gene testing.

RESULTS

Sixteen patients were included (12 females; mean age at presentation: 4.2 years, range: 14 days to 17 years), with surveillance imaging encompassing the following modalities: chest X-ray and CT; abdominal, pelvic and neck US; and brain and whole-body MRI. Malignant lesions (68.8% of patients) included pleuropulmonary blastoma (5), pineoblastoma (3), ovarian Sertoli-Leydig cell tumor (1), embryonal rhabdomyosarcoma (1) and renal sarcoma (1); benign lesions (37.5% of patients) included thyroid cysts (2), thyroid nodules (2), cystic nephroma (2), renal cysts (1) and pineal cyst (1). A common lesional appearance observed across modalities and organs was defined as the "cracked windshield" sign.

CONCLUSION

The spectrum of DICER1-related tumors and the young age at presentation suggest early surveillance of at-risk patients is critical, while minimizing exposure to ionizing radiation.

New roles for Dicer in the nucleolus and its relevance to cancer

The nucleolus is a distinct compartment of the nucleus responsible for ribosome biogenesis. Mis-regulation of nucleolar functions and of the cellular translation machinery has been associated with disease, in particular with many types of cancer. Indeed, many tumor suppressors (p53, Rb, PTEN, PICT1, BRCA1) and proto-oncogenes (MYC, NPM) play a direct role in the nucleolus, and interact with the RNA polymerase I transcription machinery and the nucleolar stress response. We have identified Dicer and the RNA interference pathway as having an essential role in the nucleolus of quiescent Schizosaccharomyces pombe cells, distinct from pericentromeric silencing, by controlling RNA polymerase I release. We propose that this novel function is evolutionarily conserved and may contribute to the tumorigenic pre-disposition of DICER1 mutations in mammals.

Structural Foundations of RNA Silencing by Argonaute

Nearly every cell in the human body contains a set of programmable gene-silencing proteins named Argonaute. Argonaute proteins mediate gene regulation by small RNAs and thereby contribute to cellular homeostasis during diverse physiological process, such as stem cell maintenance, fertilization, and heart development. Over the last decade, remarkable progress has been made toward understanding Argonaute proteins, small RNAs, and their roles in eukaryotic biology. Here, we review current understanding of Argonaute proteins from a structural prospective and discuss unanswered questions surrounding this fascinating class of enzymes.

Pediatric Cystic Nephroma Is Morphologically, Immunohistochemically, and Genetically Distinct From Adult Cystic Nephroma

The term cystic nephroma has traditionally been used to refer to 2 neoplasms, a lesion in adults that is now thought to be part of the spectrum of mixed epithelial stromal tumor (MEST) and a pediatric lesion that has been associated with mutations in the DICER1 gene. A direct detailed morphologic, immunohistochemical, and genetic comparison of these 2 lesions has not been performed. In this study, we compare the morphologic features, immunoreactivity for estrogen receptor and inhibin, and DICER1 genetic status of 12 adult cystic nephroma/MEST (median age 50.5 y, all females) and 7 pediatric cystic nephroma (median age 1.3 y, male:female=6:1). Both lesions (11 of 12 adult cases, 6 of 7 pediatric cases) frequently demonstrated subepithelial accentuation of stromal cellularity, though the increased cellularity frequently included inflammatory cells in the pediatric cases. All adult and pediatric cases labeled for estrogen receptor; however, whereas most (83%) of adult cases labeled for inhibin at least focally, no pediatric case labeled for inhibin. Most adult cases (58%) demonstrated wavy, ropy collagen in association with cellular stroma, whereas this was not found in pediatric cases. 86% of pediatric cases demonstrated DICER1 mutations, whereas only 1 of 10 adult cases demonstrated a DICER1 mutation. In summary, although cellular stroma and estrogen receptor immunoreactivity are commonly present in both adult and pediatric cystic nephroma, ropy collagen and inhibin immunoreactivity are far more common in adult cystic nephroma/MEST, whereas DICER1 mutations are far more prevalent in pediatric cystic nephroma. These results support the current World Health Organization Classification's separation of adult and pediatric cystic nephromas as distinct entities.

Multimorbidity and Genetic Characteristics of DICER1 Syndrome Based on Systematic Review

It has been reported that germline DICER1 mutations correlate with a distinctive human disease syndrome. Many published studies within this field have been conducted based on rare cases. We systematically searched bibliographic databases, including PubMed, Embase, and COSMIC for articles which are related to diseases covered by DICER1 syndrome. The weighted summary of mutation frequencies among patients with pleuropulmonary blastoma (PPB), cystic nephroma (CN), and Sertoli-Leydig cell tumor (SLCT) were calculated. Forty-nine eligible articles were included. In total, 72 cases with multimorbidity of DICER1 syndrome were identified. More females (n=46, 64%) presented with multimorbidity than males (n=18, 25%) and the remaining 8 patients' sex were unknown. Nineteen of 72 patients with multimorbidity suffered from another disease that was not yet included in DICER1 syndrome, which would provide potential phenotypes of DICER1 syndrome. The germline DICER1 mutation frequencies in PPB, CN, and SLCT were 66.9%, 73.2%, and 57.1%, respectively. The somatic DICER1 mutation frequencies of PPB, CN, and SLCT were 92.4%, 87.9%, and 43.3%, respectively. Majority of patients with multimorbidity of DICER1 syndrome were mutation positive individuals so that multimorbidity may suggest the possible germline mutation of these patients and their relatives.

Sequencing of DICER1 in sarcomas identifies biallelic somatic DICER1 mutations in an adult-onset embryonal rhabdomyosarcoma

BACKGROUND

Sarcomas are rare and heterogeneous cancers. We assessed the contribution of DICER1 mutations to sarcoma development.

METHODS

The coding region of DICER1 was sequenced in 67 sarcomas using a custom Fluidigm Access Array. The RNase III domains were Sanger sequenced in six additional sarcomas to identify hotspot DICER1 variants.

RESULTS

The median age of sarcoma diagnosis was 45.7 years (range: 3 months to 87.4 years). A recurrent embryonal rhabdomyosarcoma (ERMS) of the broad ligament, first diagnosed at age 23 years, harboured biallelic pathogenic somatic DICER1 variants (1 truncating and 1 RNase IIIb missense). We identified nine other DICER1 variants. One somatic variant (p.L1070V) identified in a pleomorphic sarcoma and one germline variant (c.2257-7A>G) may be pathogenic, but the others are considered to be benign.

CONCLUSIONS

We show that deleterious DICER1 mutations underlie the genetic basis of only a small fraction of sarcomas, in particular ERMS of the urogenital tract.

Quantification of Thyroid Cancer and Multinodular Goiter Risk in the DICER1 Syndrome: A Family-Based Cohort Study

CONTEXT

The risk of thyroid cancer and multinodular goiter (MNG) in DICER1 syndrome, a rare tumor-predisposition disorder, is unknown.

OBJECTIVE

To quantify the risk of thyroid cancer and MNG in individuals with DICER1 syndrome.

DESIGN

Family-based cohort study.

SETTING

National Institutes of Health (NIH) Clinical Center (CC).

PARTICIPANTS

The National Cancer Institute DICER1 syndrome cohort included 145 individuals with a DICER1 germline mutation and 135 family controls from 48 families.

INTERVENTIONS

Each individual completed a detailed medical history questionnaire. A subset underwent a 3-day evaluation at the NIH CC.

MAIN OUTCOME MEASURES

The cumulative incidence of MNG (or thyroidectomy) was quantified using the complement of the Kaplan-Meier product limit estimator. We compared the observed number of thyroid cancers in the NCI DICER1 cohort with matched data from the Surveillance, Epidemiology, and End Results (SEER) Program. We performed germline and somatic (thyroid cancer, MNG) DICER1 sequencing.

RESULTS

By the age of 40 years, the cumulative incidence of MNG or thyroidectomy was 75% in women and 17% in men with DICER1 syndrome compared with 8% of control women (P < 0.001) and 0% of control men (P = 0.0096). During 3937 person-years of observation, individuals with DICER1 syndrome had a 16-fold increased risk of thyroid cancer (95% confidence interval, 4.3 to 41; P < 0.05) compared with the SEER rates. Of 19 MNG nodules and 3 thyroid cancers, 16 (84%) and 3 (100%), respectively, harbored germline and somatic pathogenic DICER1 mutations.

CONCLUSIONS

We propose a model of thyroid carcinogenesis in DICER1 syndrome. Early-onset, familial, or male MNG should prompt consideration of the presence of DICER1 syndrome.

A rare presentation of cystic nephroma in a young adult

Cystic nephroma is a rare benign renal lesion with non-specific presenting symptoms. This tumour has a bimodal age distribution presenting in children between 3 months and 2 years and in adults over 30 years of age. There is male preponderance with a 2:1 male to female ratio in the childhood whereas it is commoner in females in adults. It is uncommon in the age-group of 5 years–30 years. We describe a case of cystic nephroma in a 25-year-old female which was managed by partial nephrectomy.

A Comprehensive Review of Pediatric Tumors and Associated Cancer Predisposition Syndromes

An understanding of the role of inherited cancer predisposition syndromes in pediatric tumor diagnoses continues to develop as more information is learned through the application of genomic technology. Identifying patients and their relatives at an increased risk for developing cancer is an important step in the care of this patient population. The purpose of this review is to highlight various tumor types that arise in the pediatric population and the cancer predisposition syndromes associated with those tumors. The review serves as a guide for recognizing genes and conditions to consider when a pediatric cancer referral presents to the genetics clinic.

Multicystic nephroma masquerading as hydatid cyst: a diagnostic challenge

Background

Multicystic nephroma is an uncommon, non-familial renal neoplasm that is usually benign. About 200 cases of this lesion have been described in the literature.

Case presentation

We report on a Sudanese child who presented at the age of two and a half years with an abdominal mass, clinical and radiological features favored the diagnosis of hydatid cyst which is endemic in this African tropical country, and the diagnosis of multicystic nephroma was only possible after histopathological examination.

Conclusion

Multicystic nephroma is a rare benign tumour with an excellent prognosis. Clinical and radiological differentiation of multicystic nephroma from hydatid cyst is difficult. Thus, histopathological examination of the surgical specimens seems to be the only feasible method of making the correct diagnosis.

Childhood cancer predisposition syndromes-A concise review and recommendations by the Cancer Predisposition Working Group of the Society for Pediatric Oncology and Hematology

Heritable predisposition is an important cause of cancer in children and adolescents. Although a large number of cancer predisposition genes and their associated syndromes and malignancies have already been described, it appears likely that there are more pediatric cancer patients in whom heritable cancer predisposition syndromes have yet to be recognized. In a consensus meeting in the beginning of 2016, we convened experts in Human Genetics and Pediatric Hematology/Oncology to review the available data, to categorize the large amount of information, and to develop recommendations regarding when a cancer predisposition syndrome should be suspected in a young oncology patient. This review summarizes the current knowledge of cancer predisposition syndromes in pediatric oncology and provides essential information on clinical situations in which a childhood cancer predisposition syndrome should be suspected.

[WHO classification 2016 and first S3 guidelines on renal cell cancer: What is important for the practice?]

The first S3 guidelines on renal cell cancer cover the practical aspects of imaging, diagnostics and therapy as well as the clinical relevance of pathology reporting. This review summarizes the changes in renal tumor classification and the new recommendations for reporting renal cell tumors. The S3 guidelines recommend the 2016 World Health Organization (WHO) classification of renal cell tumors. Novel renal cell tumor entities and provisional or emerging renal cell tumor entities of the 2016 WHO classification of renal tumors are discussed. The S3 guidelines for renal cell cancer also recommend the use of the WHO/International Society of Urologic Pathology (ISUP) grading system for clear cell and for papillary renal cell carcinomas, which replaces the previously used Fuhrman grading system.

Multicystic dysplastic kidney: Assessment of the need for renal scintigraphy and the safety of conservative treatment

OBJECTIVES

To assess the need for implementing renal scintigraphy in the diagnosis of the multicystic dysplastic kidney (MCDK) and the safety of its conservative treatment.

MATERIAL AND METHODS

A retrospective study of patients with unilateral MCDK was conducted at our centre from January 2005 to August 2015. We calculated the positive predictive value (PPV) of ultrasonography, taking renal scintigraphy and pathology as the gold standard. We calculated a survival curve according to the Kaplan-Meier method to assess the annual probability of spontaneous resolution of the multicystic kidney.

RESULTS

Fifty-six patients were identified, 48 (85.7%) of whom had a prenatal diagnosis. Thirty eight (67.9%) of the patients were males, and the left side was affected in 33 (58.9%) of the patients. We observed associated urological abnormalities in 22 (39.29%) patients, with vesicoureteral reflux the most common (8, 14.29%). Seven patients (12.5%) developed renal failure. Forty-nine (87.5%) patients developed compensatory contralateral renal hypertrophy. Of the 33 patients who underwent surgery, the pathology results confirmed the MCDK diagnosis in 32. Compared with scintigraphy and pathology, the PPV of ultrasonography was 100% and 97%, respectively. The rate of spontaneous involution was 5.4% at 3 months of life, 11.3% at 2 years and 38.4% at 5 years.

CONCLUSIONS

In our experience, the conservative treatment of MCDK, until at least 5 years of age, is safe. Our data suggest that performing scintigraphy is not required for these patients, which means lower radiation exposure, as well as financial savings.

Pediatric renal and genitourinary tract tumors and the contributions of Dr. Louis "Pepper" Dehner therewith

Dr. Louis "Pepper" Dehner is an internationally renowned surgical pathologist, especially in the subspecialty of pediatric pathology. Although his clinical and academic expertise are broad, with over 400 published articles, some of his most intriguing contributions have been in the area of pediatric renal and genitourinary pathology. This review focuses on the entities in these following organ systems where he has focused his efforts: malignant rhabdoid tumor, renal medullary carcinoma, Ewing sarcoma/peripheral neuroectodermal tumor, and the DICER1-related lesions cystic nephroma, embryonal rhabdomyosarcoma of the uterine cervix, and Sertoli-Leydig cell tumor.

Ovarian tumors related to intronic mutations in DICER1: a report from the international ovarian and testicular stromal tumor registry

Germline DICER1 mutations have been described in individuals with pleuropulmonary blastoma (PPB), ovarian Sertoli-Leydig cell tumor (SLCT), sarcomas, multinodular goiter, thyroid carcinoma, cystic nephroma and other neoplastic conditions. Early results from the International Ovarian and Testicular Stromal Tumor Registry show germline DICER1 mutations in 48 % of girls and women with SLCT. In this report, a young woman presented with ovarian undifferentiated sarcoma. Four years later, she presented with SLCT. She was successfully treated for both malignancies. Sequence results showed a germline intronic mutation in DICER1. This mutation results in an exact duplication of the six bases at the splice site at the intron 23 and exon 24 junction. Predicted improper splicing leads to inclusion of 10 bases of intronic sequence, frameshift and premature truncation of the protein disrupting the RNase IIIb domain. A second individual with SLCT was found to have an identical germline mutation. In each of the ovarian tumors, an additional somatic mutation in the RNase IIIb domain of DICER1 was found. In rare patients, germline intronic mutations in DICER1 that are predicted to cause incorrect splicing can also contribute to the pathogenesis of SLCT.

Metachronous anaplastic sarcoma of the kidney and thyroid follicular carcinoma as manifestations of DICER1 abnormalities

Anaplastic sarcoma of the kidney (ASK) is a tumor found in the pediatric age group and shows many histopathological similarities to pleuropulmonary blastoma (PPB). We present a 12-year-old girl diagnosed with ASK and, 3 years later, with thyroid follicular carcinoma (TFC) with DICER1 abnormalities. Germline insertion/deletion (p. G1809_S1814delinsA) and independent somatic mutations (p. E1705K in ASK, p. E1813D in TFC) were identified. All of these abnormalities are in the catalytic domain of RNase IIIb. Single-nucleotide polymorphism genotyping microarray revealed independent copy number alterations (trisomy 8, monosomy 10, loss of 17p, and partial gain of 17q in ASK; trisomy 5 and partial loss of Xq in TFC). The copy number alteration pattern of ASK was similar to the pattern previously reported in PPB. The present case implies that ASK is a renal counterpart of PPB and that ASK with DICER1 abnormalities should be suspected in a broader age group than PPB.

Pulmonary and pleural pathology: Contributions of Dr. Louis "Pepper" Dehner

Dr. Louis Dehner is an internationally renowned surgical pathologist who has published multiple textbooks and has authored or co-authored nearly 400 original articles in the medical literature. While many think of him as a pediatric pathologist, he has contributed to the literature across virtually the entire breadth of surgical pathology, and the lung and pleura is no exception. This review will highlight Dr. Dehner׳s contributions to the pulmonary and pleural pathology literature in the areas of infectious disease, medical lung disease and transplant pathology, and a number of neoplasms of the lung and pleura, with the remainder of this manuscript dedicated to the still evolving story of the pleuropulmonary blastoma as the signature contribution of his long and distinguished career.

Gene mutations in Cushing's disease

Cushing's disease (CD) is a severe (and potentially fatal) disease caused by adrenocorticotropic hormone (ACTH)-secreting adenomas of the pituitary gland (often termed pituitary adenomas). The majority of ACTH-secreting corticotroph tumors are sporadic and CD rarely appears as a familial disorder, thus, the genetic mechanisms underlying CD are poorly understood. Studies have reported that various mutated genes are associated with CD, such as those in menin 1, aryl hydrocarbon receptor-interacting protein and the nuclear receptor subfamily 3 group C member 1. Recently it was identified that ubiquitin-specific protease 8 mutations contribute to CD, which was significant towards elucidating the genetic mechanisms of CD. The present study reviews the associated gene mutations in CD patients.

Evolution of Renal Cysts to Anaplastic Sarcoma of Kidney in a Child With DICER1 Syndrome

Anaplastic sarcoma of kidney (ASK) is a rare neoplasm recently associated with DICER1 mutations. We report a child with germline DICER1 mutation who developed ASK in preexisting septated renal cysts, which were likely cystic nephroma. From age 2.5 to 6 years, sonographic imaging illustrated changes in the size and number of renal cysts, followed at age 8.8 years by a mass, pathologically an ASK. Lung cysts resected in infancy were diagnosed retrospectively as pleuropulmonary blastoma. Both tumors had acquired somatic DICER1 mutations. Ultrasonographic evolution of renal cysts to ASK has not previously been documented. Children with both pulmonary and renal cysts are candidates for DICER1 mutation testing.