An association of pleuropulmonary blastoma and cystic nephroma: possible genetic association

Clinical and Molecular Characteristics and Outcome of Cystic Partially Differentiated Nephroblastoma and Cystic Nephroma: A Narrative Review of the Literature

Simple Summary

Although renal tumors in children are mostly solid masses, cystic renal tumors also occur. The most likely diagnoses for cystic renal tumors include cystic partially differentiated nephroblastoma and cystic nephroma. Since these tumors are rare, limited information on the treatment, clinical and molecular characteristics, and outcome is available. In this review, we aim to summarize all reported patients with cystic partially differentiated nephroblastoma and cystic nephroma. We identified 113 cystic partially differentiated nephroblastoma and 167 cystic nephroma patients. Surgery was the cornerstone of treatment for both tumor types and chemotherapy was generally not recommended. Cystic nephroma was often related to DICER1-mutations and second tumors, whereas cystic partially differentiated nephroblastoma was related to somatic hyperdiploidy, although testing was rare. The outcome for both tumors is favorable. This study provides information for treatment decisions and stresses the importance of a central review of radiology and pathology, as well as referral to a clinical geneticist.

Abstract

In children presenting with a predominantly cystic renal tumor, the most likely diagnoses include cystic partially differentiated nephroblastoma (CPDN) and cystic nephroma (CN). Both entities are rare and limited information on the clinical and molecular characteristics, treatment, and outcome is available since large cohort studies are lacking. We performed an extensive literature review, in which we identified 113 CPDN and 167 CN. The median age at presentation for CPDN and CN was 12 months (range: 3 weeks–4 years) and 16 months (prenatal diagnosis–16 years), respectively. No patients presented with metastatic disease. Bilateral disease occurred in both entities. Surgery was the main treatment for both. Two/113 CPDN patients and 26/167 CN patients had previous, concomitant, or subsequent other tumors. Unlike CPDN, CN was strongly associated with somatic (n = 27/29) and germline (n = 12/12) DICER1-mutations. Four CPDN patients and one CN patient relapsed. Death was reported in six/103 patients with CPDN and six/118 CN patients, none directly due to disease. In conclusion, children with CPDN and CN are young, do not present with metastases, and have an excellent outcome. Awareness of concomitant or subsequent tumors and genetic testing is important. International registration of cystic renal tumor cohorts is required to enable a better understanding of clinical and genetic characteristics.

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.

Rhabdoid Tumor Predisposition Syndrome and Pleuropulmonary Blastoma Syndrome

In recent years, hereditary cancer syndromes have developed greater interest in the scientific community. Two such syndromes, rhabdoid tumor syndrome and pleuropulmonary blastoma (DICER1) syndrome, have appeared increasingly in the literature. This review will discuss these two syndromes in terms of clinical parameters, associated tumors, and genetic associations.

Temporal order of RNase IIIb and loss-of-function mutations during development determines phenotype in pleuropulmonary blastoma / DICER1 syndrome: a unique variant of the two-hit tumor suppression model

Pleuropulmonary blastoma (PPB) is the most frequent pediatric lung tumor and often the first indication of a pleiotropic cancer predisposition,  DICER1 syndrome, comprising a range of other individually rare, benign and malignant tumors of childhood and early adulthood. The genetics of  DICER1-associated tumorigenesis are unusual in that tumors typically bear neomorphic missense mutations at one of five specific “hotspot” codons within the RNase IIIb domain of  DICER 1, combined with complete loss of function (LOF) in the other allele. We analyzed a cohort of 124 PPB children for predisposing  DICER1 mutations and sought correlations with clinical phenotypes. Over 70% have inherited or  de novo germline LOF mutations, most of which truncate the  DICER1 open reading frame. We identified a minority of patients who have no germline mutation, but are instead mosaic for predisposing  DICER1 mutations. Mosaicism for RNase IIIb domain hotspot mutations defines a special category of  DICER1 syndrome patients, clinically distinguished from those with germline or mosaic LOF mutations by earlier onsets and numerous discrete foci of neoplastic disease involving multiple syndromic organ sites. A final category of PBB patients lack predisposing germline or mosaic mutations and have sporadic (rather than syndromic) disease limited to a single PPB tumor bearing tumor-specific RNase IIIb and LOF mutations. We propose that acquisition of a neomorphic RNase IIIb domain mutation is the rate limiting event in  DICER1-associated  tumorigenesis, and that distinct clinical phenotypes associated with mutational categories reflect the temporal order in which LOF and RNase IIIb domain mutations are acquired during development.

Temporal order of RNase IIIb and loss-of-function mutations during development determines phenotype in pleuropulmonary blastoma / DICER1 syndrome: a unique variant of the two-hit tumor suppression model

Pleuropulmonary blastoma (PPB) is the most frequent pediatric lung tumor and often the first indication of a pleiotropic cancer predisposition,  DICER1 syndrome, comprising a range of other individually rare, benign and malignant tumors of childhood and early adulthood. The genetics of  DICER1-associated tumorigenesis are unusual in that tumors typically bear neomorphic missense mutations at one of five specific "hotspot" codons within the RNase IIIb domain of  DICER 1, combined with complete loss of function (LOF) in the other allele. We analyzed a cohort of 124 PPB children for predisposing  DICER1 mutations and sought correlations with clinical phenotypes. Over 70% have inherited or  de novo germline LOF mutations, most of which truncate the  DICER1 open reading frame. We identified a minority of patients who have no germline mutation, but are instead mosaic for predisposing  DICER1 mutations. Mosaicism for RNase IIIb domain hotspot mutations defines a special category of  DICER1 syndrome patients, clinically distinguished from those with germline or mosaic LOF mutations by earlier onsets and numerous discrete foci of neoplastic disease involving multiple syndromic organ sites. A final category of PBB patients lack predisposing germline or mosaic mutations and have sporadic (rather than syndromic) disease limited to a single PPB tumor bearing tumor-specific RNase IIIb and LOF mutations. We propose that acquisition of a neomorphic RNase IIIb domain mutation is the rate limiting event in  DICER1-associated  tumorigenesis, and that distinct clinical phenotypes associated with mutational categories reflect the temporal order in which LOF and RNase IIIb domain mutations are acquired during development.

Exploring the association Between DICER1 mutations and differentiated thyroid carcinoma

CONTEXT

Carriers of germline DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 syndrome. Thyroid abnormalities are a common finding in DICER1 syndrome with multinodular goiter frequently present in many families in which a germline DICER1 mutation is segregating. Differentiated thyroid carcinoma (DTC) is infrequently seen in such pedigrees. In addition to germline DICER1 mutations, specific somatic mutations have been identified in the DICER1 ribonuclease IIIb catalytic domain in several tumor types.

OBJECTIVE

We aimed to determine whether such characteristic somatic DICER1 mutations are present in DTCs that arise within germline DICER1 mutation carriers.

DESIGN AND SETTING

The study involved an opportunistic collection of 3 cases of DTC arising in individuals suspected to have DICER1 syndrome and hospital-based ascertainment and testing was implemented.

RESULTS

We identified somatic DICER1 mutations in 3 DTCs arising in unrelated germline DICER1 mutation carriers, all of whom had been diagnosed in infancy with pleuropulmonary blastoma (PPB), were treated with chemotherapy, exposed frequently to diagnostic radiation, and subsequently developed DTC. The somatic mutations occurred within the DICER1 ribonuclease IIIb domain, affecting highly conserved amino acid residues central to the catalytic activity of the domain.

CONCLUSION

This report of somatic DICER1 mutations in DTC strengthens the association between DTC and the DICER1 syndrome. The possible association between germline DICER1 mutations, PPB treatment, and the risk of subsequent DTC must be considered by clinicians when treating PPB.

Pleuropulmonary blastoma in an infant

Pleuropulmonary blastomas (PPB) are rare and highly aggressive tumors. Herein, we report an infantile case of type III PPB. A 9-mth-old boy presented to our unit with a history of cough and tachypnea for 2 days. Chest computed tomography revealed a mass in the left upper lobe, emphysema in the left upper lung, and mediastinum and heart shifted towards the right. The mass was removed completely by left upper lobectomy and histology confirmed diagnosis of type III PPB. The immature blastematous tissue was positive for vimentin while benign epithelium was positive for epithelial membrane antigen and cytokeratin. No lymph nodule metastasis was found in the 7 lymph nodules obtained from the hilum of the lung near the tumor. Currently, the patient is under close follow-up and is doing well.

Pulmonary cysts in early childhood and the risk of malignancy

Surgery for congenital and early childhood lung cysts is often dictated by symptoms such as respiratory distress, infection or pneumothorax. Asymptomatic cysts present a therapeutic dilemma: surgical intervention and "conservative" observation have advocates. The risk of malignancy in such cysts is considered by some an indication for surgical intervention and is reviewed in this paper. Pleuropulmonary blastoma (PPB) is the most frequent malignancy associated with childhood lung cysts. Although rare, PPB occurs predictably in certain clinical and familial situations. This unique biology of PPB can inform the cyst management decision. The earliest manifestation of PPB is a malignant lung cyst in young children, clinically and radiographically indistinguishable from benign congenital lung cysts. Histopathologic examination differentiates cystic PPB from the benign cystic variants. Surgical excision of cystic PPB (with or without chemotherapy) cures approximately 85-90% of children. If not excised, cystic PPB evolves to cystic/solid or solid high-grade sarcoma (cure rate 45-60%) by age 2-6 years. Numerous reports of "malignancy in a congenital lung cyst" are now understood as the characteristic progression of cystic PPB. PPB is genetically determined in many cases. Detailed family history may reveal the hallmarks of PPB in the patient or young relatives: a unique constellation of diseases including lung cysts, cystic nephroma, childhood cancers, stromal sex-chord ovarian tumors, seminomas or dysgerminomas, intestinal polyps, thyroid hyperplasias, and hamartomas. Pneumothorax and multifocal/bilateral lung cysts also characterize PPB. These diagnoses predict that a lung cyst is more likely PPB than a benign congenital cyst. Patients fitting this pattern deserve histologic diagnosis. The genetic basis for this heritable syndrome is unknown but is being actively investigated.

Pleuropulmonary blastema with cystic nephroma - A rare presentation and surgical dilemma

Pleuropulmonary balstema with cystic nephroma is a rare dual pathology of pediatric age group. The etiopathogenesis of this entity is not known, still researches indicate towards a common genetic cause. We report a case of this dual pathology in a one and half year old male. Till now only 5 cases have been reported.

Renal tumours of childhood: an update

The role of the pathologist has been fundamental in the progress of the treatment of paediatric renal tumours. There are different philosophies in the treatment of these tumours, and there have been many recent advances in the areas of chemotherapy, identification of new entities, prognostic histological criteria following treatment and molecular prognostic and diagnostic features. This review discusses the different approaches of the different treatment protocols from Europe and North America, and reviews staging criteria, prognostic criteria and also the different tumour entities.

Gain of chromosome 8q is a frequent finding in pleuropulmonary blastoma

Pleuropulmonary blastomas are rare malignant intrathoracic tumors of early childhood. They appear as a pulmonary- and/or pleural-based mass and their pathogenesis and relationship to other pediatric solid tumors is not well understood. In this study, paraffin-embedded material of five cases of pleuropulmonary blastoma was analyzed for genetic alterations by comparative genomic hybridization and five genetic loci by fluorescence in situ hybridization. Comparative genomic hybridization identified aberrations in all pleuropulmonary blastomas, including four amplifications in three tumors at chromosomes 5q33-34, 11q22.2-ter, 15q25-ter, and 19q11-13.2. The most frequent DNA gains involved 8q11-22.2 (four cases) and 20q (two cases), whereas the most common losses included 9p21-24 (two cases) and 11p14 (three cases). Chromosome 8 gains were confirmed by fluorescent in situ hybridization, resulting in the detection of up to five copies of chromosome 8 centromeres per nucleus. In the two surviving patients, chromosome 8 gains were the only genetic abnormality, suggesting that this might be an early event in pleuropulmonary blastoma carcinogenesis. The identification of new genetic alterations as well as the confirmation of previously reported ones (especially 8q gains) in pleuropulmonary blastoma should help to improve our understanding of both the molecular mechanisms underlying the tumorigenesis of pleuropulmonary blastoma and the relationship of pleuropulmonary blastoma with other pediatric tumors.

Familial Multilocular Cystic Nephroma: A Variant of a Unique Renal Neoplasm

Multilocular cystic nephroma (MCN) is a benign renal lesion believed to be unilateral and nonfamilial. We present 2 cases of MCN in 2 brothers. The older brother had a 10-cm MCN and required radical nephrectomy, and the younger brother had bilateral lesions (6 cm and 3 cm) for which nephron-sparing surgery was possible. Both children underwent chest computed tomography to rule out pleuropulmonary blastoma. These cases suggest a genetic link to the pathogenesis of this lesion is possible and that although MCN can involve the collecting system, it can still be treated with partial nephrectomy.

Familial association of pleuropulmonary blastoma with cystic nephroma and other renal tumors: a report from the International Pleuropulmonary Blastoma Registry

OBJECTIVE

To characterize the association of pleuropulmonary blastoma (PPB) with cystic nephroma (CN) and other renal tumors.

STUDY DESIGN

Complete clinicopathologic review of cases from the International PPB Registry and literature.

RESULTS

We identified 18 patients with PPB associated with 20 renal tumors (15 CN), either in themselves or family members. All patients with PPB were <5 years of age. All but one of the renal diagnoses were made before 4 years of age. Eleven children had both PPB and renal tumor, one of whom also had a sibling with CN. Six children with PPB alone had one or more family members with CN. The mother of one child with PPB had Wilms' tumor. Pulmonary disease was bilateral in four patients. Renal disease was bilateral in three patients. Two children with PPB and bilateral renal cystic tumors also had intussusceptions because of small bowel juvenile polyps. In six families, dysplasia/neoplasia affected organs other than lung and kidney.

CONCLUSIONS

CN or related tumors were found in 9.2% of 152 Registry-reviewed PPB cases. The occurrence of rare pulmonary and renal tumors together in patients and/or family members, the early age of onset, and the multiplicity of tumors is compatible with a constitutional genetic predisposition.