[Childhood pleuropulmonary blastoma: a clinicopathologic study of 16 cases]

OBJECTIVE

To study the clinicopathological and immunohistochemical features, histogenesis and prognosis of pleuropulmonary blastoma (PPB) in children.

METHODS

PPB specimens from 16 pediatric cases with an age ranging from 1 year and 7 months to 5 years and 3 months (mean age of 3 years) were retrieved and analyzed by routine histological, immunohistochemical and electron methods.

RESULTS

Among 16 patients, there were 2 type I, 7 type II and 7 type III PPB cases. Type I PPB as multilocular cystic structure, consisted of thin fibrous wall lining the respiratory epithelium, subepithelial primitive blastema or immature mesenchymal cells, with or without rhabdomyoblastic differentiation or cartilage; Type II PPB as cystic-solid tumor, comparing with type I, consisted of intracystic components with appearance of anaplastic tumor cells. Type III PPB consisted of completely solid mass, the same as the solid region of type II, had mixed pattern including blastema, undifferentiated spindle-cell proliferations and sarcomas. In addition, anaplastic tumor cells and intra-and extra- cytoplasmic eosinophilic globules were also commonly present. Epithelial components in PPB were benign. Immunohistochemical study showed primitive mesenchymal differentiation of tumors. All cases were positive for vimentin, desmin, myogenin and SMA in tumors with skeletal muscle differentiation, S-100 was positive in tumors with cartilage differentiation. All tumors were negative for synaptophysin, CD99, and CD117. Benign epithelial components were positive for AE1/AE3 and EMA. In 12 cases, electron microscopy revealed few organelles in the primitive mesenchymal cells and rich heterochromatin in mesenchymal cells, the latter also demonstrating cytoplasmic myofilament dysplasia. Nine cases had clinical follow-up ranging from 5 to 48 months, of which 4 patients died.

CONCLUSIONS

PPB is a rare lung neoplasm of children under the age of 6 years, with distinct pathological morphology. PPB may arise from lung or pleura mesenchymal cells and has a poor clinical outcome.

Combined small cell carcinoma with pulmonary blastoma and adenocarcinoma: Case report and clonality analysis

We describe a rare tumor occurring in the left pulmonary lobe of a 71-year-old Japanese man. The tumor, which was resected by left lower lobectomy, measured 65 x 50 x 50 mm. Histologic examination revealed papillary adenocarcinoma in small cell carcinoma, and chondrosarcoma. Also, the blastemal cells were located between the small cell carcinoma and the chondrosarcoma, and intermingled with both components. In blastemal cells, some glands resembled a well-differentiated fetal adenocarcinoma. The tumor was diagnosed as combined small cell carcinoma with pulmonary blastoma and papillary adenocarcinoma according to the 2004 WHO classification. Immunohistochemically, the small cell carcinoma expressed TTF-1, pancytokeratin, CD56, synaptophysin, and S100 protein, while blastemal cells expressed vimentin, desmin, smooth muscle actin, CD56, and S100 protein. To investigate whether the tumor was clonal or not, p53 gene mutation of each tumor component was analyzed by laser-captured microdissection, polymerase chain reaction-single-strand conformation polymorphism and direct sequencing. Despite the histologic complexity, all components showed the same mutation at exon5 of the p53 gene. These results indicate that the tumor was clonal and arose from a relatively primitive cell, and that p53 mutation occurred before histologic metamorphosis or differentiation.

Well-differentiated fetal adenocarcinoma of the lung: Cytomorphologic features on fine-needle aspiration with emphasis on use of β-catenin as a useful diagnostic marker

Well-differentiated fetal adenocarcinoma (WDFA), also known as low grade adenocarcinoma of the fetal lung type, is a rare pulmonary neoplasm now considered to be a variant of lung adenocarcinoma rather than a type of pulmonary blastoma. Upregulation of the Wnt signaling pathway with subsequent aberrant nuclear/cytoplasmic beta-catenin expression has been recently described in these tumors providing a possible pathogenetic role for this gene in WDFA. We describe the cytomorphologic findings of a case of WDFA in a 36-yr-old female patient and emphasize the diagnostic utility of aberrant nuclear/cytoplasmic expression of beta-catenin as an adjunct to the correct preoperative recognition of this tumor on aspiration cytology.

Fine-needle aspiration cytology of pleuropulmonary blastoma: a case report with unusual features

Pleuropulmonary blastoma (PPB) is a rare and aggressive intrathoracic neoplasm of childhood, typically presenting as a pulmonary and/or pleural-based mass with cystic, solid, or combined features. Histologically, the tumor is well characterized with a mixture of primitive mesenchymal and variably differentiated sarcomatous components, and the cytologic features described in the three previous reports are also compatible to the histologic ones. Now, we present another case of PPB showing unusual features. A 3-yr-old boy presented with a pleural- or chest wall-based tumor. The fine-needle aspiration cytologic smears were highly cellular with poorly differentiated cells showing variable size and shape rather than those of typical blastemal cells. The histologic findings were also distinctive, exhibiting diffuse sheets of poorly differentiated cells without typical blastemal cell component. Diagnosis was confirmed by the support of immunohistochemical and ultrastructural features. The patient underwent a typical aggressive clinical course to death within 8 mo after diagnosis.

Gains of chromosome 8 are confined to mesenchymal components in pleuropulmonary blastoma

Pleuropulmonary blastoma, an aggressive tumor that is emerging as a distinct entity of childhood, is characterized by mesenchymal elements (including undifferentiated blastema and often cartilaginous, rhabdomyoblastic, or fibroblastic differentiation) and epithelium-lined spaces. We investigated two patients with pleuropulmonary blastoma, a 3-year-old boy and an 11-year-old girl, both with large cystic masses replacing one lung. In both children, the post-chemotherapy resection specimens showed more maturation of rhabdomyoblasts and more nuclear pleomorphism in all mesenchymal cell lines, compared with biopsies sampled before treatment. Karyotypic analysis demonstrated gains in chromosome 8 in both cases and 17p deletion in one case. Fluorescent in situ hybridization analysis demonstrated that the chromosome 8 gains were present in all mesenchymal elements, including undifferentiated blastematous, rhabdomyoblastic, fibroblastic, and chondroblastic areas. Epithelial cells showed no chromosome 8 gains. The chromosome 8 aberrations were not appreciably different in pre- versus post-chemotherapy tissue. Our findings substantiate previous reports that polysomy of chromosome 8 is a consistent feature of pleuropulmonary blastoma. Further, they indicate that clonal proliferation in pleuropulmonary blastoma is restricted to the malignant mesenchymal elements, supporting the notion that the epithelial components of this tumor are non-neoplastic.

Cell adhesion molecules and intermediate filaments on embryonal childhood tumors

We describe the expression of 18 different cell adhesion molecules, intermediate filaments and Ki-67 antigen in embryonal childhood tumors. 5 microns frozen sections from 15 nephroblastomas, 13 neuroblastomas, six rhabdomyosarcomas, one Ewing sarcoma and one pulmonary blastoma were analyzed by the alkaline phosphatase anti-alkaline phosphatase (APAAP) method using murine monoclonal antibodies. All tumors exhibited high proliferation rates as did, surprisingly, the nephroblastoma specimens despite pre-treatment with chemotherapy. Polysialylated NCAM was demonstrated on all tumor types, but Ewing sarcoma and expression correlated inversely with cell differentiation. In contrast, E-cadherin was present solely on tubulus like cells in nephroblastomas. This cell type showed a coexpression of cytokeratin and vimentin, giving evidence of its intermediate position between the mesenchyme and epithelium. In neuroblastomas, CD44s (hyaluronate receptor) expression was increased with cell differentiation. ICAM-1, VCAM-1 and E-selectin were mostly expressed in regressive areas of pretreated nephroblastoma specimens where a considerable infiltration of leukocytes was noted as well. Since endothelial and leukocyte adhesion molecules were distinctly less expressed in all other tumors investigated, these findings may indicate immunological processes as a consequence of or as supplement to the chemotherapeutical effect on nephroblastoma cells. Integrin receptors were not found on the surface of tumor cells, and therefore, at least those investigated seem to be of secondary importance to the biology of the tumors studied herein. In conclusion, our investigations demonstrate that, besides achieving a secure and prompt differentiation between various embryonal tumors, applying the panel of monoclonal antibodies proposed herein gives interesting insights into the histogenesis, biology and metastatic potential of pediatric malignancies.

Proliferative activity, p53 accumulation and neoangiogenesis in pulmonary carcinosarcomas and pulmonary blastomas

Carcinosarcoma and pulmonary blastomas are rare biphasic tumors. Lung cancer pathogenesis is a multistep process. Proliferative activity, p53 accumulation and angiogenesis are of well-known relevance and ought to be evaluated in the epithelial and mesenchymal components of these tumors. Using antibodies against Ki-67 epitope MIB1 and proliferating cell nuclear antigen (PC 10) in 10 carcinosarcomas, tumors revealed a significantly higher proliferative activity in the epithelial component compared with the mesenchymal component in the MIB1 reaction (p = 0.013). In three pulmonary blastomas of the biphasic subtype, proliferative activity was similar in both parts. In five of 10 carcinosarcomas and in one of three pulmonary blastomas, accumulation of the p53 epitopes Pab 1801 and/or DO-1 was found. At the tumor front, a significantly higher vessel density was found compared with the central parts (p < or = 0.015) using a monoclonal antibody against human endothelium (CD 31). No differences were found between carcinosarcomas and pulmoblastomas. Higher proliferative activity in carcinosarcomas revealed a better prognosis regarding metastasis behavior (p = 0.05) and tumor-associated death in the follow-up (p < or = 0.017). p53 accumulation and microvessel density were of no prognostic value. This is in contrast to results in non-small cell lung cancer, pointing to a different biologic behavior.

Pulmonary adenocarcinomas of the fetal lung type: a clinicopathologic study indicating differences in histology, epidemiology, and natural history of low-grade and high-grade forms

Seven cases of high-grade adenocarcinoma of fetal lung type (H-FLAC) are compared with nine cases of pulmonary endodermal tumor resembling fetal lung or low-grade adenocarcinoma of fetal lung type (L-FLAC). Of the seven patients with of H-FLAC, four were men and three were women. All of the patients but one were in their 60s or 70s. Five patients were smokers. After resection of the tumor, three patients died of metastases, two patients are alive with no evidence of disease, and two patients died of a postoperative complication. Histologically, H-FLAC and L-FLAC have both complex glandular structures resembling fetal lung and neuroendocrine differentiation. Two cases of H-FLAC had stromal proliferation typical of biphasic pulmonary blastoma. The H-FLAC was distinguished from L-FLAC by the presence of disorganized glands, large vesicular nuclei, prominent nucleoli, pronounced anisonucleosis, absence of morules, transition to conventional adenocarcinoma, broad areas of necrosis, desmoplastic stroma, overexpression of p53 protein, and production of alpha-fetoprotein. High and low grades of FLAC explain discrepancies in previously reported clinicopathologic features of FLAC. The H-FLAC needs to be distinguished from L-FLAC. Both forms may have stromal components, so both have been referred to as blastomas. The H-FLAC represents the prototype of so-called pulmonary blastoma predominantly seen in the elderly, whereas L-FLAC and its biphasic form predominate in the middle-aged population.

p53 and MDM2 immunostaining in pulmonary blastomas and bronchogenic carcinomas

Pulmonary blastomas (PBs) are rare primary malignancies that include adult types: biphasic pulmonary blastoma (BPB) and well-differentiated fetal adenocarcinoma (WDFA); and childhood type: pleuropulmonary blastoma (PPB). Their pathogenesis and relationship to bronchogenic carcinoma (BCA) are controversial. To determine whether or not PB share molecular pathological features with BCA, the authors immunostained three BPB, three WDFA, three PPB, and 80 standard BCA for p53 protein and MDM2 protein, gene products believed to be significant in the pathogenesis of BCA. Paraffin-embedded tissue sections were immunostained with monoclonal antibody to p53 and MDM2 proteins. Strong intranuclear staining in greater than 10% of cells was considered positive. Three (50%) BPB and WDFA stained for p53 and five (83%) for MDM2. None of the PPB stained for p53, and one PPB did not stain for either p53 or MDM2. Five of six adult type PB occurred in smokers, whereas none of the PPB was associated with smoking. Seventy-five (94%) of the BCA stained for MDM2 and 46 (61%) for p53. Immunostaining patterns for p53 and MDM2 in adult types of PB, and not PPB, appear similar to those for BCA. This may suggest that adult type PB, but not childhood PB, have a similar pathogenesis to BCA.

Pulmonary blastoma: an ultrastructural and immunohistochemical study with special reference to nuclear filament aggregation

A case is presented of pulmonary blastoma occurring in the right upper lobe of a 25-year-old man without distinct clinical features and laboratory abnormality. Light microscopic analysis revealed that the tumor was composed of branching glands and morulae embedded in a primitive but bland mesenchyme. Immunohistochemically the epithelial cells were immunoreactive for cytokeratins, S-100 protein, protein gene product 9.5, chromogranin A, calcitonin, and Ki-67 (MIB-1); the mesenchymal cells were immunoreactive for vimentin, actin, cytokeratins, and Ki-67; and all the tumor cells were negative for p53, estrogen receptor protein, and human chorionic gonadotropin beta. Characteristically, many epithelial cells contained optically clear nuclei which were immunoreactive for biotin (M743). Electron microscopic analysis revealed that the optically clearing change was due to replacement of the central area of the nuclei by a mass of parallel-arranged 7- to 10-nm filaments, and biotin-immunoreactive products were mainly localized in the nuclear matrix. Additionally, spherical bodies were identified in the cytoplasm of the nuclear filament-aggregated cells, suggestive of an intimate pathogenetic association of the two morphological abnormalities. The similarity of the aggregated nuclear filaments to those observed in gestational endometrium and ovarian endometrioid carcinoma implies that a similar mechanism plays a role in the pathogenesis of these abnormalities.