Pleuropulmonary Blastoma: A Single-center Case Series of 6 Patients

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.

Treatment and prognosis of pleuropulmonary blastoma: A single-center report of 31 cases

OBJECTIVES

Pleuropulmonary blastoma (PPB) is a very rare and highly aggressive neoplasm occurring in children, mostly under 6 years of age. We assessed the clinical characteristics, treatment modalities, treatment outcomes, and prognostic factors affecting survival in patients with PPB treated at our institution over a 10-year period to improve the prognosis.

METHODS

From November 2008 to November 2019, 31 children (21 boys and 10 girls) with a median age of 30 months (ranging, 22 days to 54 months) were treated at our institution. Here we describe the patient characteristics, treatment modalities, and treatment outcomes. The Kaplan-Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS). Log-rank test was performed for comparison between groups.

RESULTS

Three children were lost to follow-up and two were dead due to postoperative complications. Of the 26 patients included in the follow-up, 16 PPB patients displayed tumor-free survival. The 5-year PFS and OS were 60.4% and 60.1% respectively. By stratified statistical analysis, the 5-year PFS and OS of type I PPB were 100%, while those of type III PPB were 43.7% and 43%, respectively. The 5-year PFS and OS of complete tumor resection were 76.5% and 75.6%, respectively, while those with tumor residue were 31.3%. The 5-year PFS and OS combined with chemotherapy were 62.2% and 61.6%, respectively, while those without chemotherapy were 0%.

CONCLUSIONS

PPB is an aggressive neoplasm. The main factors related to the prognosis of PPB are pathological type, tumor resection degree, and postoperative adjuvant therapy.

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.

Epidemiological features and survival outcomes in patients with malignant pulmonary blastoma: a US population-based analysis

BACKGROUND

Pulmonary blastoma (PB) is a rare lung primary malignancy with poorly understood risk factors and prognosis. We sought to investigate the epidemiologic features and long-term outcomes of PB.

METHODS

A population-based cohort study was conducted to quantify the death risk of PB patients. All subjects diagnosed with malignant PB from 1988 to 2016 were screened from the Surveillance, Epidemiology and End Results database. Cox regression model of all-cause death and competing risk analysis of cause-specific death were performed.

RESULTS

We identified 177 PB patients with a median survival of 108 months. The 5 and 10-year survival rate in all PB patients were 58.2 and 48.5%, as well as the 5 and 10-year disease-specific mortality were 33.5 and 38.6%. No sex or race disparities in incidence and prognosis was observed. The death risk of PB was significantly associated with age at diagnosis, clinical stage, histologic subtype and surgery treatment (p<0.01). On multivariable regression analyses, older age, regional stage and no surgery predicted higher risk of both all-cause and disease-specific death in PB patients.

CONCLUSION

We described the epidemiological characteristics of PB and identified its prognostic factors that were independently associated with worse clinical outcome.

Clinical analysis of early death in children with pleuropulmonary blastoma in a single center in China

OBJECTIVE

Pleuropulmonary blastoma (PPB) is a rare malignant tumor in childhood that is highly invasive and has poor prognosis. We retrospectively analyzed patients with PPB who died within 30 days in hopes of providing a basis for improving diagnosis and treatment.

METHODS

We retrospectively reviewed six children with PPB who died within 30 days of admission at our hospital from January 2004 to March 2018, including their clinical features, pathological diagnosis, course of treatment, and major causes of death.

RESULTS

Six patients (two female, four male; median age, 38 months) were included. All patients presented with respiratory symptoms. Chest imaging showed that all tumors had diameters greater than 10 cm, with varying degrees of serous effusion. Four patients underwent ultrasound-guided fine-needle aspiration (FNA), one patient underwent exploratory thoracotomy, and one underwent partial tumor resection. Five cases were type III, and another was type II. Four patients developed adverse events while waiting for pathological results after FNA, and four patients were treated with chemotherapy but their tumors failed to decrease in size one to two weeks later. The median hospitalization to death time was 17 days (range, 5-24 days).

CONCLUSIONS

PPB often presents with respiratory symptoms that rapidly develop into respiratory distress. The rapid tumor enlargement contributes to the disease's progression. Chemoreduction in such tumors is not obviously effective, and the mortality rate is high. The main causes of death were respiratory failure and sepsis. Further clinical studies will be required to evaluate the role of initial biopsy compared with upfront total excision.