Adult Pulmonary Blastoma: A Case Report with Spectrum of Rare Manifestations.

Pulmonary blastoma (PB) is an exceedingly rare and aggressive malignant lung neoplasm that has distinct biphasic morphology. In this report, we document rare manifestations and molecular alterations in PB. A 59-year-old non-smoker female, presented with cough and hemoptysis for 4 months. The high-resolution computed tomography chest scan showed a 3.5x2.7 cm mass in the basal segment of the left lung. Positron emission tomography and computed tomography revealed a fluorodeoxyglucose avid lobulated mass in the superior segment of the lower lobe of the left lung. On core biopsy, the diagnosis of pleomorphic carcinoma in a background of adenocarcinoma was made. A definite diagnosis of pulmonary blastoma was established on the left lung lobectomy specimen based on morphological and immunohistochemical findings. Post-surgical biopsy from the scalp swelling showed metastatic deposits. On Next Generation Sequencing (NGS), in addition to conventional CTNNB1 gene mutation, new pathogenic MYCN and ATM gene mutations were detected. Post-chemotherapy, the patient was doing well after 10 months of close follow-up. PB exhibited rare associations in the form of non-smoker status, scalp metastasis, and MYCN and ATM gene mutations on NGS in addition to conventional CTNNB1 gene mutation. Large cohort studies are required to discover the incidence, significance and therapeutic implications of these co-existing pathogenic molecular alterations in PB.

Cytomorphologic and immunocytochemical characterization of pediatric pleuropulmonary blastoma with a comprehensive review of the literature.

INTRODUCTION: Pleuropulmonary blastoma (PPB) is a rare, aggressive, primary intrathoracic malignancy typically seen in infancy and early childhood. Accurate distinction from congenital cystic lung lesions is crucial due to significant prognostic and therapeutic differences. Cytologic features have rarely been described. Establishing a cytodiagnosis is challenging owing to its rarity, lack of awareness, and multiple morphologic mimics. MATERIALS AND METHODS: This was a retrospective study conducted over 8 years. The histopathology and cytopathology databases were searched for all pediatric PPB cases. The corresponding cytologic samples were reviewed to identify characteristic features that can help distinguish PPB from its mimics. RESULTS: There was a total of six cases of pediatric PPB reported during the study period. Of these, four (66.7%) presented as intrathoracic, and two (33.3%) as pleural-based masses. Cytology smears showed discretely scattered and perivascular arrangements of round-oval tumor cells with background eosinophilic stromal material. The tumor cells were mildly pleomorphic (n = 3) with round nuclei, fine chromatin, inconspicuous nucleoli, and scanty cytoplasm; however, three cases showed marked anaplasia, and one each showed necrosis and rhabdoid differentiation. On immunocytochemistry (4/6), these were positive for vimentin and desmin and negative for WT1, chromogranin, SALL4, cytokeratin, CD45, and CD99. FISH (1/6) did not show N-Myc amplification. CONCLUSIONS: Knowledge of the characteristic cytomorphological and immunocytochemical features of PPB is vital to establish a prompt and accurate cytodiagnosis with appropriate clinicoradiologic correlation.

No Pathogenic DICER1 Gene Variants in a Cohort Study of 28 Children With Congenital Pulmonary Airway Malformation.

BACKGROUND: Distinguishing congenital pulmonary airway malformations (CPAMs) from pleuropulmonary blastoma (PPB) can be challenging. Previously diagnosed patients with CPAM may have been misdiagnosed and we may have missed DICER1-associated PPBs, a diagnosis with important clinical implications for patients and their families. To gain insight in potential misdiagnoses, we systematically assessed somatic DICER1 gene mutation status in an unselected, retrospective cohort of patients with a CPAM diagnosis. METHODS: In the Amsterdam University Medical Center (the Netherlands), it has been standard policy to resect CPAM lesions. We included all consecutive cases of children (age 0-18 years) with a diagnosis of CPAM between 2007 and 2017 at this center. Clinical and radiographic features were reviewed, and DICER1 gene sequencing was performed on DNA retrieved from CPAM tissue samples. RESULTS: Twenty-eight patients with a surgically removed CPAM were included. CPAM type 1 and type 2 were the most common subtypes (n = 12 and n = 13). For 21 patients a chest CT scan was available for reassessment by two pediatric radiologists. In 9 patients (9/21, 43%) the CPAM subtype scored by the radiologists did not correspond with the subtype given at pathology assessment. No pathogenic mutations and no copy number variations of the DICER1 gene were found in the DNA extracted from CPAM tissue (0/28). CONCLUSIONS: Our findings suggest that the initial CPAM diagnoses were correct. These findings should be validated through larger studies to draw conclusions regarding whether systematic DICER1 genetic testing is required in children with a pathological confirmed diagnosis of CPAM or not. LEVEL OF EVIDENCE: Level IV.

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.

Classic biphasic pulmonary blastoma: A case report and review of the literature from 2000 to 2022.

Classic biphasic pulmonary blastoma (CBPB), a distinct type of lung cancer, is a dual-phasic tumor characterized by the co-existence of low-grade fetal adenocarcinoma and primitive mesenchymal stroma. Accounting for less than 0.1% of surgically removed lung cancers, CBPB commonly presents in individuals during their fourth to fifth decades of life, with smoking as a significant risk factor. The optimal management strategy entails surgical resection, supplemented by chemotherapy to improve prognosis. The frontline chemotherapeutic agents typically include platinum agents and etoposide, with preoperative neoadjuvant chemotherapy potentially enabling operability for initially inoperable cases. In recent years, targeted therapies, such as antiangiogenic agents, have emerged as promising new treatment strategies for CBPB. For patients exhibiting brain metastases or deemed inoperable, radiation therapy proves to be a crucial therapeutic component. CBPB prognosis is adversely affected by factors such as early metastasis, tumor size exceeding 5 cm, and tumor recurrence. In this regard, serological markers have been identified as valuable prognostic indicators. To exemplify, we recount the case of a 44-year-old female patient with CBPB, wherein serum lactate dehydrogenase levels showed significant diagnostic value. This report further incorporates a comprehensive review of CBPB literature from the past 22 years.

A rare case of Pleuropulmonary blastoma type III with Immunohistochemical Study.

Here we intend to document a rare case of PPB type III in a 2-year male presenting with an extensive tumor occupying the right hemithorax with immunohistochemical (IHC) study. Pleuropulmonary blastoma (PPB) is a rare variably aggressive, dysodontogenetic, childhood primary intrathoracic malignancy which in up to 25% of cases can be extrapulmonary with attachment to the parietal pleura. It is found in pediatric population under 5 years of age. It was initially proposed as a distinct entity by Manivel et al. in 1988. PPB is a proliferation of primitive mesenchymal cells that initially form air-filled cysts lined by benign-appearing epithelium (type I, cystic). Later on, the mesenchymal cells outgrow the cysts with formation of focal solid areas (type II, solid and cystic) and finally, mainly solid mass (type III, solid PPB).

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.

Pulmonary blastoma that was first diagnosed as dedifferentiated chondrosarcoma using medical thoracoscopy: A case report.

RATIONALE: Pulmonary blastoma is an extremely rare and highly aggressive tumor. Only a few hundred cases of pulmonary blastoma have been reported. In other cases, a definitive diagnosis is often made through surgical resection. The use of preoperative histopathological sampling in diagnosing was of limited value because of the variety of pulmonary blastoma histology. And there was no literature that the first biopsy was attempted with medical thoracoscopy for diagnosis. PATIENT CONCERNS: A 65-year-old man presented to our hospital with pleural effusion and lung mass. DIAGNOSES: The patient was initially diagnosed with dedifferentiated chondrosarcoma by medical thoracoscopic biopsy but the final diagnosis was pulmonary blastoma through bilobectomy. INTERVENTIONS: Medical thoracoscopy, and video-assisted thoracoscopic surgery (bilobectomy) followed by adjuvant chemotherapy. OUTCOMES: After surgical resection of the tumor, adjuvant chemotherapy has been performed 5 cycles at 3 weeks intervals, and there was no evidence of recurrence on follow-up computed tomography performed 4 months after surgery. LESSONS: Medical thoracoscopy is useful for the diagnosis of indeterminate pleural effusion; however, caution is needed when confirming rare malignancies, such as pulmonary blastoma. Although surgical resection is the treatment of choice, appropriate adjuvant chemotherapy to improve the prognosis may be necessary if there is pleural metastasis.

[Pleuropneumoblastoma: a case report about a rare pediatric tumor]. / Pleuropneumoblastome: une tumeur pédiatrique rare (à propos d'un cas).

Pleuropulmonary blastoma is a rare intrathoracic tumor in children. It is associated with poor prognosis and diagnosis is based on histological examination. We conducted a didactic study involving a 3-year-old child with severe acute respiratory distress associated with hemothorax; radiological and thoracoscopic examination suggested malignant pleuropulmonary process. Anatomopathological examination with radio-clinical comparison allowed for the diagnosis of solid-cystic pleuropulmonary blastoma type II. Unfortunately, given the severity of the clinical features, the child died within a few weeks due to multiple organ failure. Pathologist experience is very important to recognize the disease and to start adequate treatment as soon as possible. This allows for a tumor regression rate up to 90% after neoadjuvant treatment and a 5-year survival rate of at least 53% for aggressive forms: solid and solido-cystic tumors.

Pleuropulmonary blastoma masquerading as pneumothorax in a patient with a ventricular septal defect.

Pleuropulmonary blastoma is a rare pediatric primary lung tumor. We report a case of a child with Down syndrome and a large ventricular septal defect presenting with pleuropulmonary blastoma initially misdiagnosed as spontaneous pneumothorax. Following tube thoracostomy drainage of the pneumothorax, the child underwent surgical closure of the ventricular septal defect. However, the postoperative period was complicated by recurrent left pleural collection requiring prolonged intercostal tube drainage and two thoracotomies to evacuate the necrotic pleural material. The biopsy of the necrotic material was suggestive of type III pleuropulmonary blastoma. In view of the high propensity of metastasis associated with this variant of a tumor, the patient was started on chemotherapy. This case report highlights the possibility of pleuropulmonary blastoma presenting as pneumothorax and emphasizes the need to consider the etiology, before intervening in a child presenting with spontaneous pneumothorax.

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.

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.

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.

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.

Pulmonary blastoma: a comprehensive overview of a rare entity.

INTRODUCTION: Pulmonary blastoma is a rare malignancy, accounting for less than 0.5% of primary lung tumors. It belongs to the group of pulmonary sarcomatoid carcinomas, and it is typically characterized by a biphasic pattern of an epithelial and a mesenchymal component. Only a few hundred cases have been reported worldwide. The aim of this study is to review and critically assess the literature regarding pulmonary blastoma. MATERIAL AND METHODS: A narrative literature review of PubMed database from the inception of the database up to January 2021, limited to the English language, was conducted, using combinations of the following keywords: "pulmonary blastoma", "biphasic pulmonary blastoma", "sarcomatoid carcinoma". RESULTS: Pulmonary blastoma is composed of an epithelial and a mesenchymal malignant component. Regarding pathogenesis, the origin of the biphasic cell population remains elusive. Characteristic immunohistochemical stains are supportive of diagnosis.Clinically, the symptomatology is non-specific, while 40% of the cases are asymptomatic. It is diagnosed at a younger agecompared to other types of lung cancer, and it is often non-metastatic at diagnosis allowing for surgical treatment. Data on management and survival are scarce and mainly come from isolated cases. Advances on targeted therapy may provide novel treatment options. Given the rarity of the cases, multicenter collaboration is needed in order to establish therapeutic guidelines.

Programmed Death Ligand 1 Expression and Related Markers in Pleuropulmonary Blastoma.

INTRODUCTION: Pleuropulmonary blastoma (PPB), a rare childhood neoplasm of the lung, is linked to pathogenic DICER1 variants. We investigated checkpoint inhibitor markers including Programmed Death Ligand 1 (PD-L1), PD1, CD8 and tumor mutational burden (TMB) in PPB. MATERIAL AND METHODS: Cases were collected from departmental archives and the International PPB/DICER1 Registry. Immunohistochemistry (IHC) for PD-L1, PD-1, CD8 and DNA mismatch repair (MMR) genes were performed. In addition, normal-tumor paired whole exome sequencing (WES) was performed in two cases. RESULTS: Twenty-five PPB cases were studied, consisting of Type I (n = 8, including 2 Ir), Type II (n = 8) and Type III (n = 9). PD-L1 combined positive score (CPS) of 1, 4 and 80 was seen in three (3/25, 12.0%) cases of Type II PPB with negative staining in the remaining cases. PD-1 and CD8 stains demonstrated positive correlation (P < .05). The density of PD1 and CD8 in the interface area was higher than within tumor (P < .05). The MMR proteins were retained. TMB was 0.65 mutations/Mb in type II PPB with high expression of PD-L1, and 0.94 mutations/Mb in one negative PD-L1 case with metastatic tumor. CONCLUSION: A small subpopulation of PPB patient might benefit from checkpoint immunotherapy due to positive PD-L1 staining.

Type II Pleuropulmonary Blastoma in a 4 Month Old Infant with Negative Dicer1 Mutation on Next Generation Sequencing.

INTRODUCTION: Pleuropulmonary blastoma (PPB) is a rare, but aggressive tumor in the pediatric population. PPB is a dysontogenetic neoplasm of childhood that involves the lungs and/or pleura. Young relatives of children with PPB have an increased incidence of neoplasias and dysplasias. According to tumor tissue histopathology, PPB evolves from a cystic to solid state over time. PPBs can be sub-classified as type I (purely cystic), type II (having both cystic and solid elements), and type III (completely solid). Type II and type III tumors may be associated with metastasis, with the brain being the most common metastatic site. Due to the primitive nature of cells in the tumor mass, PPBs are very aggressive tumors that are resistant to therapy. The prognosis depends on the histopathology content and tumor type. Respiratory problems are the main complaint and diagnosis can be made only after additional examinations. Genetic relations through family members are associated with mutations in the DICER1 gene; between 60-80% of patients with PPBs are positive for DICER1 mutations. Mosaicism has also been reported. AIM: The aim was to present a case of a 4 month-old infant with type II PPB, who had a negative result for DICER1 mutation in next generation sequencing. To detail the clinical presentation of this patient, we present radiographic and ultrasound findings and results of histopathological analysis, as well as genetic and scintigraphic findings and chemotherapy treatment. CASE REPORT: Here we describe the genetic analysis of a patient with PPB who was negative for mutations in DICER1 and who had no relatives with disease. This patient underwent radical resection of the tumor and began therapy, but subsequently died after developing leukopenia and sepsis. CONCLUSION: This case provides an example of a patient with PPB who was negative for DICER1 mutation upon genetic analysis and emphasizes the potential for disease that does not involve mutation of this gene.

Pleuropulmonary blastoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations.

Pleuropulmonary blastoma (PPB) is a rare cancer occurring mainly during early childhood and often associated with germline DICER1 mutations. It is classified by the macroscopic appearance into three interrelated clinico-pathologic entities on a developmental continuum. Complete tumor resection is a main prognostic factor and can be performed at diagnosis or after neoadjuvant treatment that includes chemotherapy and in some cases radiotherapy. Optimal modalities of neo- or adjuvant treatments can be challenging taking into account potential long-term toxicities in this young population. This paper presents the recommendations for diagnosis and treatment of children and adolescents with PPB elaborated by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) within the European Union-funded project PARTNER (Paediatric Rare Tumours Network - European Registry).

Multimodality treatment including whole pleura radiation therapy for DICER1-associated pediatric pleuropulmonary blastoma.

Limited data are available regarding radiation therapy in pediatric pleuropulmonary blastoma (PPB). We report the case of a 3-year-old girl with type II PPB successfully treated with trimodality therapy including multiagent chemotherapy, resection, and whole pleura radiation therapy. While longer follow-up is required to confirm ultimate local tumor control and long-term post-treatment sequelae, currently 3.5 years following therapy, she is well, without recurrent disease or observable toxicity. The goal of this report is to add our experience to the literature regarding PPB, its management, and treatment, as prospective randomized controlled trials are not feasible due to the rarity of this disease.