Prevalence of lung cysts in adolescents and adults with a germline DICER1 pathogenic/likely pathogenic variant: a report from the National Institutes of Health and International Pleuropulmonary Blastoma/DICER1 Registry.

BACKGROUND: Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1-related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants. METHODS: Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis. RESULTS: In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB. CONCLUSION: Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention.

Pediatric pleuropulmonary blastoma: analysis of four cases.

BACKGROUND: Pleuropulmonary Blastoma (PPB) is an extremely uncommon, highly aggressive tumor that arises from either the lungs or pleura. According to Dehner, PPB was classified into three groups: type I (cystic), type II (mixed), and type III (solid). Type I tends to occur more commonly in infants and has a more favorable prognosis compared to types II and III. This tumor is very rare in pediatric age group; hence, there is no consensus on the optimal treatment regimen for it to date. Type I tumors, which resemble congenital lung cysts, can eventually progress to more aggressive type II and type III tumors. This article aims to increase general awareness of this pathology, clinical presentation, and differential diagnosis in order to identify this rare entity early in its course. By presenting 4 such cases, we highlight that PPB can be missed early in diagnosis and it is important to be alert when putting this rare tumor in differential diagnosis of cystic lung lesions. METHODS: A retrospective study was conducted between 2015 and 2020 involving patients who had a definitive diagnosis of PPB with emphasis on clinical presentation, preoperative imaging studies, intra-operative findings, pathological reports, ancillary treatment, and outcomes. All patients were followed up every 6 months to monitor local recurrence and distant metastasis by undergoing physical exam and non-contrast enhanced CT of the chest. The primary outcome is to identify the mortality and morbidity (recurrence and distant metastasis) of PPB for cases admitted in our institute. RESULTS: Four children were diagnosed with PPB during the study period. Clinically, patients presented with manifestations ranging from respiratory distress, fever to obstructive shock and radiologically, 2 cases were presented with mediastinal mass and the other 2 presented with pneumothorax. Regrettably, none of the cases were diagnosed pre-operatively. One lesion proved to be type I, 2 were type II and one was type III. All cases underwent chemotherapy using the combination of vincristine, Adriamycin and cyclophosphamide (VAC regimen). Recurrence was detected in a type II case, around 2 years after operation, and the other type II case developed brain metastasis that was discovered 3 years after operation. Type I case showed no local or distant metastasis. CONCLUSION: A prompt preoperative diagnosis and workup of cases of PPB is crucial to enable optimal intervention intraoperatively and early postoperative treatment. Though it is uncommon, PPB should be considered in the differential diagnosis of cystic lung lesions.

Outcomes in ovarian Sertoli-Leydig cell tumor: A report from the International Pleuropulmonary Blastoma/DICER1 and Ovarian and Testicular Stromal Tumor Registries.

OBJECTIVE: Sertoli-Leydig cell tumors (SLCTs) are rare sex cord-stromal tumors, representing <0.5% of all ovarian tumors. We sought to describe prognostic factors, treatment and outcomes for individuals with ovarian SLCT. METHODS: Individuals with SLCT were enrolled in the International Pleuropulmonary Blastoma/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Medical records were systematically abstracted, and pathology was centrally reviewed when available. RESULTS: In total, 191 participants with ovarian SLCT enrolled, with most (92%, 175/191) presenting with FIGO stage I disease. Germline DICER1 results were available for 156 patients; of these 58% had a pathogenic or likely pathogenic germline variant. Somatic (tumor) DICER1 testing showed RNase IIIb hotspot variants in 97% (88/91) of intermediately and poorly differentiated tumors. Adjuvant chemotherapy was administered in 40% (77/191) of cases, and among these, nearly all patients received platinum-based regimens (95%, 73/77), and 30% (23/77) received regimens that included an alkylating agent. Three-year recurrence-free survival for patients with stage IA tumors was 93.6% (95% CI: 88.2-99.3%) compared to 67.1% (95% CI: 55.2-81.6%) for all stage IC and 60.6% (95% CI: 40.3-91.0%) for stage II-IV (p < .001) tumors. Among patients with FIGO stage I tumors, those with mesenchymal heterologous elements treated with surgery alone were at higher risk for recurrence (HR: 74.18, 95% CI: 17.99-305.85). CONCLUSION: Most individuals with SLCT fare well, though specific risk factors such as mesenchymal heterologous elements are associated with poor prognosis. We also highlight the role of DICER1 surveillance in early detection of SLCT, facilitating stage IA resection.

Anaplastic sarcoma of the kidney (DICER1-sarcoma of the kidney): A report from the International Pleuropulmonary Blastoma/DICER1 Registry.

BACKGROUND: Anaplastic sarcoma of the kidney (ASK) is a DICER1-related neoplasm first identified as a distinctive tumor type through the evaluation of unusual cases of putative anaplastic Wilms tumors. Subsequent case reports identified the presence of biallelic DICER1 variants as well as progression from cystic nephroma, a benign DICER1-related neoplasm. Despite increasing recognition of ASK as a distinct entity, the optimal treatment remains unclear. METHODS: Individuals with known or suspected DICER1-related tumors including ASK were enrolled in the International Pleuropulmonary Blastoma/DICER1 Registry. Additionally, a comprehensive review of reported cases of ASK was undertaken, and data were aggregated for analysis with the aim to identify prognostic factors and clinical characteristics to guide decisions regarding genetic testing, treatment, and surveillance. RESULTS: Ten cases of ASK were identified in the Registry along with 37 previously published cases. Staging data, per Children's Oncology Group guidelines, was available for 40 patients: 13 were stage I, 12 were stage II, 10 were stage III, and five were stage IV. Outcome data were available for 37 patients. Most (38 of 46) patients received upfront chemotherapy and 14 patients received upfront radiation. Two-year event-free survival (EFS) for stage I-II ASK was 81.8% (95% confidence interval [CI]: 67.2%-99.6%), compared with 46.6% EFS (95% CI: 24.7%-87.8%) for stage III-IV (p = .07). Two-year overall survival (OS) for stage I-II ASK was 88.9% (95% CI: 75.5%-100.0%), compared with 70.0% (95% CI: 46.7%-100.0%) for stage III-IV (p = .20). Chemotherapy was associated with improved EFS and OS with hazard ratios of 0.09 (95% CI: 0.02-0.31) and 0.08 (95% CI: 0.02-0.42), respectively. CONCLUSION: ASK is a rare DICER1-related renal neoplasm. In the current report, we identify clinical and treatment-related factors associated with outcome including the importance of chemotherapy in treating ASK. Ongoing data collection and genomic analysis are indicated to optimize outcomes for children and adults with these rare tumors.

Type I and Ir pleuropulmonary blastoma (PPB): A report from the International PPB/DICER1 Registry.

BACKGROUND: Pleuropulmonary blastoma (PPB) is the most common lung cancer of infancy and early childhood. Type I PPB is a purely cystic lesion that has a microscopic population of primitive small cells with or without rhabdomyoblastic features and may progress to type II or III PPB, whereas type Ir lacks primitive small cells. METHODS: Children with suspected PPB were enrolled in the International PPB/DICER1 Registry. Pathology was centrally reviewed, and follow-up was ascertained annually. RESULTS: Between 2006 and 2022, 205 children had centrally reviewed type I or Ir PPB; 39% of children with type I and 5% of children with type Ir PPB received chemotherapy. Outcomes were favorable, although 11 children (nine with type I and two with type Ir PPB) experienced progression to type II/III (n = 8) or regrowth of type I PPB at the surgical site (n = 3), none of whom received chemotherapy before progression. Age and cyst size in combination were more suitable than either factor alone in predicting whether a particular lesion was type I or Ir PPB. CONCLUSIONS: For young children with type I PPB, outcomes are favorable, but complete resection is indicated because of the risk for progression. Chemotherapy may be useful in a subset of children at increased risk for recurrence/progression. Efforts to risk stratify children with type I PPB to optimize outcomes while reducing treatment-related side effects are underway.

Case 320: Intrathyroidal Thymic Tissue.

HISTORY: A 7-year-old boy with a history of pleuropulmonary blastoma after resection 6 years prior and germline DICER1 mutation was being monitored by physicians at a multidisciplinary genetic predisposition clinic. He demonstrated no evidence of recurrent pleuropulmonary blastoma, and his renal US, chest radiographic, and ocular screening examination results remained normal. Per age-directed screening guidelines, he underwent thyroid US. He had no signs or symptoms of hyper- or hypothyroidism. Physical examination was notable for the absence of thyromegaly or palpable nodule. US at 12-month follow-up showed no change in size or appearance of the left lobe (not shown). However, at this time, the Thyroid Imaging Reporting and Data System (TI-RADS) classification scheme was applied to the stable left lobe finding. The findings were discussed at a multidisciplinary thyroid nodule conference, and the decision was made to bring the patient back for a short-term follow-up for limited unenhanced MRI without sedation. A diagnosis was made based on the follow-up imaging findings.

Health-related quality of life in children and adolescents with pleuropulmonary blastoma: A report from the International PPB/DICER1 Registry.

PURPOSE: Pleuropulmonary blastoma (PPB) is the most common lung cancer of infancy and early childhood and is associated with germline DICER1 variants. Type I and Ir PPB are cystic lesions treated surgically, with a subset of children with type I receiving chemotherapy. Type II and III are more aggressive lesions, treated with surgery, intensive chemotherapy and potentially radiation. We sought to assess health-related quality of life (HRQoL) in children with PPB and known germline DICER1 variants. METHODS: Children with a diagnosis of PPB or germline DICER1 pathogenic variant without history of PPB or other DICER1-related neoplasm (DICER1+ only) were enrolled in the International PPB/DICER1 Registry. Parent reports for participants aged 2-17 years for the PedsQL v.4 and PedsQL Multidimensional Fatigue Scale v.3 were collected. Fatigue, physical, and psychosocial function scores were compared. RESULTS: Analysis included 84 participants (PPB type Ir = 20, type I = 15, type II/III = 27, DICER1+ only = 22). Total fatigue scores of participants with type I and II/III PPB were lower compared to DICER1+ only, with effect size larger in type II/III (-0.82 vs. -0.40). Total psychosocial and physical functioning scores were lower in participants with type I and type II/III PPB compared to DICER1+ only, with larger effects noted in type II/III. Female sex was suggestive of worse HRQoL for both type I/Ir and type II/III cohorts. CONCLUSIONS: These data demonstrate the importance of regular HRQoL assessment in patients with a history of PPB as well as the importance and feasibility of studying HRQoL in children with rare tumors.

Cervical Pleuropulmonary Blastoma-like Tumor Associated With DICER1 and TP53 Mutations.

We describe a very unusual cervical tumor in a 12-yr-old patient with a clinical history indicative of DICER1 syndrome. Morphologic, immunohistochemical, and molecular genetic analysis together helped to diagnose this lesion as a cervical pleuropulmonary blastoma-like tumor, associated with TP53 and DICER1 mutations. The tumor displayed usual histologic features including mixtures of embryonal rhabdomyosarcoma, sarcomatous cartilage, compact blastema, primitive spindle cells and anaplasia, akin to type III pleuropulmonary blastoma, and trabecular and retiform patterns. In addition to expanding the phenotypic spectrum of DICER1 -associated conditions, we draw attention to genotype-phenotype correlations in DICER1 -associated tumors, particularly as they relate to the discovery of a heritable tumor predisposition syndrome.

Imaging of pediatric pulmonary tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Pediatric pulmonary malignancy can be primary or metastatic, with the latter being by far the more common. With a few exceptions, there are no well-established evidence-based guidelines for imaging pediatric pulmonary malignancies, although computed tomography (CT) is used in almost all cases. The aim of this article is to provide general imaging guidelines for pediatric pulmonary malignancies, including minimum standards for cross-sectional imaging techniques and specific imaging recommendations for select entities.

Congenital Pulmonary Airway Malformations With a Reconsideration and Current Perspective on the Stocker Classification.

Congenital cystic pulmonary lesions (CCPLs) are represented by the following entities: congenital pulmonary airway malformation (CPAM), formerly congenital cystic adenomatoid malformation, extra- and intralobar sequestration (EIS), congenital lobar emphysema (overexpansion), and bronchogenic cyst. The developmental model of CPAM histogenesis by Stocker proposed perturbations designated as CPAM type 0 to type 4 without known or specific pathogenetic mechanisms along the airway from the bronchus to the alveolus. This review highlights mutational events either at the somatic level in KRAS (CPAM types 1 and possibly 3) or germline variants in congenital acinar dysplasia, formerly CPAM type 0, and pleuropulmonary blastoma (PPB), type I, formerly CPAM type 4. The potential for overt malignant progression exists in the case of PPB type I and CPAM type 1 in some cases to well-differentiated mucinous adenocarcinoma. On the other hand, CPAM type 2 is an acquired lesion resulting from interruption in lung development secondary to bronchial atresia. The latter is also regarded as the etiology of EIS whose pathologic features are similar, if not identical, to CPAM type 2. These observations have provided important insights into the pathogenetic mechanisms in the development of the CPAMs since the Stocker classification.

Scalp metastasis of pulmonary blastoma-a rare entity: Cytomorphology with differential diagnoses.

BACKGROUND: Pulmonary blastomas are exceptionally rare tumours. These tumours behave aggressively, with a propensity to metastasise to the brain and mediastinum. A definitive diagnosis of pulmonary blastoma is challenging to obtain on cytomorphology alone. CASE REPORT: We herein describe a case of a 59-year-old female who presented with a scalp lesion. The patient was diagnosed to have pulmonary blastoma on histopathology of left lower lobectomy specimen. Fine needle aspiration cytology was done from this recently developed scalp swelling. Cytomorphology supplemented with immunocytochemistry on cell block confirmed the diagnosis of a metastatic pulmonary blastoma. CONCLUSIONS: In a known case of primary pulmonary blastoma, any newly developing lesion at any anatomical site should be carefully evaluated for metastasis. If metastasis is needled and no previous histology is available, it carries a reasonable risk of erroneous interpretation. It is essential not to overlook often subtle biphasic malignant cells on the smears, which otherwise resemble other poorly differentiated tumours. Immunocytochemistry coupled with morphology is confirmatory.

Bilateral Ovarian Sertoli-Leydig Cell Tumors Harboring DICER1 Germline and Distinct Somatic Mutations: Case Report and Literature Review.

Background: DICER1 tumor predisposition syndrome is characterized by an increased risk for development of pleuropulmonary blastoma, pituitary blastoma, multinodular thyroid goiter, thyroid carcinoma, sex cord stromal tumor, cystic nephroma, embryonal rhabdomyosarcoma, and tumors of the CNS, amongst others. Of this list, only pituitary blastoma is recognized as pathognomonic for the syndrome. Case report: We describe a 15-year-old female with bilateral, asynchronous Sertoli-Leydig cell tumors (SLCT). Both tumors harbored an identical germline frameshift mutation as well as unique somatic DICER1 hot-spot point mutations. Discussion: A review of bilateral SLCTs demonstrates that all patients with available DICER1 mutation status carried a germline DICER1 mutation (100%, 9 of 9). In cases with known somatic DICER1 status on bilateral tumors, all harbored distinct somatic mutations (100%, 5 of 5). Our findings support the notion that bilateral ovarian SLCTs are indeed separate events and do not represent recurrent or metastatic disease.

Intraocular medulloepithelioma: an unusual and challenging entity in paediatric population.

Intraocular medulloepithelioma is a rare, congenital tumour of the non-pigmented ciliary epithelium. It most frequently arises from the ciliary body but can also have its origin from the retina, iris and optic nerve. The age when lesion first appears is typically around 2-10 years. Nearly 50-60% of patients having this lesion may also have secondary features such as cataract and neovascular glaucoma. Those with extrascleral medulloepithelioma are at risk for metastasis. Systemic correlation of the tumour with pleuropulmonary blastoma/DICER1 gene is reported in the literature. Here, we report a case of a 15 years old boy with one year history of right eye proptosis and painful red right eye along with decreased vision for one week. He was assessed and operated for cataract elsewhere three years back. The ophthalmology team managed him for endophthalmitis with intravenous antibiotics, followed by 2 sessions of cryotherapy and finally an enucleation of right eye was performed due to severe pain and no vision in the involved eye. His left eye, general physical examination and systemic evaluation were normal. Histopathology revealed the diagnosis of 'malignant teratoid medulloepithelioma'. Therefore, evaluation of systemic associations for DICER1 gene mutations was performed by the oncology team. For high risk feature of scleral invasion on histopathology, he was treated with chemotherapy. Since the tumour is of rare occurrence; an international expert team with vast research experience in PPB/DICER1 associated tumours was also contacted. He was registered in International PPB/DICER1 registry where a detailed central radiology and pathology review was performed. Genetic counseling and surveillance plan was also suggested by the international registry.

DICER1-associated hepatic cystic neoplasm with pleuropulmonary blastoma-like features: a novel clinicopathologic diagnosis.

This report documents a unique multicystic neoplasm of the liver in an 8-month-old boy with a heterozygous germline pathogenic DICER1 variant. This neoplasm, initially considered most likely a mesenchymal hamartoma based on imaging, demonstrated the characteristic histologic pattern of embryonal rhabdomyosarcoma residing in the subepithelial or cambium layer-like zone of the epithelial-lined cysts. Thus, although the differential diagnosis includes mesenchymal hamartoma, a young child with a multicystic mass lesion in the liver, lung, or kidney should both raise the possibility of a germline pathogenic DICER1 variant and also not be mistaken for one of the other hepatic neoplasms of childhood.

DICER1 tumor predisposition syndrome: an evolving story initiated with the pleuropulmonary blastoma.

DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation.

Phenotypic similarities within the morphologic spectrum of DICER1-associated sarcomas and pleuropulmonary blastoma: Histopathologic features guide diagnosis in the LMIC setting.

Extrapulmonary DICER1-associated sarcomas (DS) can harbor morphological features overlapping with pleuropulmonary blastoma. We report three children with intracranial and genital tract sarcomas, suspected to have DS based on a heterogeneous yet defining combination of spindle-cell sarcomatous and blastemal morphology, with rhabdomyomatous differentiation. Foci of immature cartilage at diagnosis (n = 2/3) and increased neuroepithelial differentiation at recurrence (n = 1) were noted. Morphological suspicion prompted somatic testing at reference centers, confirming likely biallelic, loss-of-function, and "hotspot" missense DICER1 variants in all three tumors. This can serve as a model for this diagnosis in resource-limited settings and has implications for germline testing, surveillance, and tumor management.

Intraventricular topotecan in the successful treatment of recurrent CNS pleuropulmonary blastoma.

Pleuropulmonary blastoma (PPB) is a rare pediatric tumor of the pleura and pulmonary mesenchyme, associated with pathogenic germline DICER1 mutations. Although the most common site of metastasis is the central nervous system (CNS), patients with CNS metastasis have dismal outcome. We report a case of a patient presenting with type II PPB and intracranial and bone metastases. We describe a multimodal therapy approach and highlight the use of intraventricular topotecan for isolated CNS recurrence. In addition, a new pathogenic germline mutation heterozygous for the c.1234delT of DICER1 was identified. Patient remains in remission 3 years after recurrence.

Pulmonary blastoma in a pregnant woman: a case report and brief review of the literature.

BACKGROUND: Pulmonary blastoma (PB) comprises a rare heterogeneous group of lung tumours typically containing immature epithelial and mesenchymal structures that imitate the embryonic lung tissue and extremely rarely occurs during pregnancy. Although cough and haemoptysis are the most common PB symptoms, they usually indicate other serious pregnancy-related complications. CASE PRESENTATION: The article presents the unusual case of a 22-year-old pregnant woman diagnosed with PB during pregnancy. CONCLUSIONS: PB is characterized by poor prognosis and patients' outcome relies on a rapid diagnosis. Surgery remains the most common and effective treatment. Due to the extreme rarity, the literature contains only single mentions of PB in pregnancy, thus its impact on the course of pregnancy and the developing fetus remains unknown.

Complete Tracheal Ring Deformity, Recurrent Pneumothoraces and Pleuropulmonary Blastoma in a Child: Coincidence or Common Genetic Cause?

Complete tracheal ring deformity (CTRD) is a rare abnormality of unknown etiology characterized by circumferentially continuous cartilaginous tracheal rings leading to variable degrees of tracheal stenosis with or without additional heart and lung malformations. Pleuropulmonary blastomas (PPB) are rare malignant mesenchymal tumors, which occur almost exclusively in young children. Pathogenic germline DICER1 variants are associated with PPB but also with other tumors like rhabdomyosarcoma or syndromic diseases like GLOW (Global developmental delay, lung cysts, overgrowth and Wilms tumor) syndrome. Here, we report a case with CTRD and recurrent pneumothoraces who additionally developed PPB on the genetic background of a pathogenic DICER1 variant.

Congenital anomalies of the large intrathoracic airways.

Congenital lung lesions are numerous but rare in individual clinical practice. They do require close multidisciplinary collaboration between health care professionals. This educational review will focus on the pathophysiology, clinical manifestations, surgical approaches, and anesthetic management of congenital anomalies of the large intrathoracic airways: congenital tracheal stenosis, tracheal agenesis, tracheal diverticulum, bronchial anomalies (tracheal, esophageal, or bridging bronchus), congenital lung malformations, lung sequestrations and Scimitar syndrome, lobar emphysema, Williams-Campbell syndrome, and pleuropulmonary blastoma. In addition, this review will illustrate common pitfalls and challenges related to the anesthesia management with emphasis on ventilation and correct endotracheal tube positioning.