Pneumothorax and pulmonary cyst in a 2-year-old child. Pleuropulmonary blastoma

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.

Clinicopathological and extensive immunohistochemical study of a type II pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare malignant dysontogenetic neoplasm primarily affecting younger children, even in newborns with an unfavorable outcome. PPB is histologically composed of a primitive, variably mixed blastematous and sarcomatous components, and exclusively subclassified as type I (purely cystic), type II (both cystic and solid elements) and type III (completely solid) by increasing histological evidence of malignancy. At present, well-documented cases or cases of truly precise presentation of either pathological or immunohistochemical findings in PPB are rare. The authors report one case of PPB in a 44-month-old child presenting as a solid and cystic mass with special emphasis on its radiological, histopathological and immunohistochemical aspects. The histological diagnosis was PPB, which would belong to the type II category.

Pleuropulmonary blastoma as characteristic cause of pneumothorax

BACKGROUND

Pleuropulmonary blastoma (PPB) is the most common lung neoplasms in childhood. Usually presents as recurrent respiratory infections and in some cases as pneumothorax.

CASE REPORT

We report the case of a 2-year-old patient that was diagnosed with PPB, that first manifested as recurrent pneumothorax. Three chest computed tomography were necessary for the diagnosis. The first 2 tomographies showed no abnormalities suggestive of malignancy. The patient had a family history of both PPB and leukemia. Three years and a half after completion of treatment, the patient is in complete remission.

CONCLUSIONS

PPB is an uncommon disease but is the most common pulmonary neoplasms in childhood. We must suspect it in patients with a suggestive family history and recurrent pneumothorax in the same location.

[Pleuropulmonary blastoma: a clinicopathological analysis]

背景与目的

胸膜肺母细胞瘤是一种罕见的且有其独特临床病理特征的恶性肿瘤，本文旨在探讨胸膜肺母细胞瘤的临床病理学特点及鉴别诊断等。

方法

收集5例胸膜肺母细胞瘤，复习患者临床资料，进行组织学及免疫组化观察，并结合文献复习分析。

结果

5例胸膜肺母细胞瘤患者年龄为21个月-47个月，平均为32.8个月；肿瘤主要位于胸腔，4例伴有胸腔积液。组织学观察：Ⅰ型胸膜肺母细胞瘤1例，呈单纯囊性；Ⅱ型胸膜肺母细胞瘤2例，呈囊实性，实性区伴横纹肌分化及灶性软骨样结节；Ⅲ型胸膜肺母细胞瘤2例，完全呈实性，可见间变性未分化肉瘤样成分。免疫组化染色显示肿瘤细胞呈Vimentin（+），部分肿瘤细胞呈Desmin和Myogenin（+），软骨样结节呈S-100（+）；PCK、EMA、CD99等均（-）。

结论

胸膜肺母细胞瘤是一种罕见的主要发生于婴幼儿肺和胸膜的高侵袭性恶性肿瘤，各亚型均有其临床病理学特点。诊断方面应与肺先天性囊性腺瘤样畸形、胚胎性横纹肌肉瘤等良恶性病变鉴别。