Molecular pathogenesis of pulmonary carcinosarcoma as determined by microdissection-based allelotyping

Gallbladder carcinosarcoma with a poor prognosis: A case report

BACKGROUND

Carcinosarcoma of the gallbladder is a rare malignant tumor with a very poor prognosis. To date, only approximately 100 patients have been reported in the English literature. The prognosis of this tumor type is poor, the preoperative diagnosis is difficult, and there is a possibility of a misdiagnosis. We present an unsuccessful case of carcinosarcoma of the gallbladder with a preoperative misdiagnosis and rapid early postoperative recurrence. Therefore, we have a deeper understanding of the poor prognosis of gallbladder carcinosarcoma (GBC) patients.

CASE SUMMARY

The patient is a 65-year-old male. He was admitted to the hospital because of right upper abdomen distending pain and discomfort for half a month. Abdominal magnetic resonance imaging revealed a polycystic mass in the right lobe of the liver and the fossa of the gallbladder. After admission, the patient was diagnosed with a liver abscess, which was treated by abscess puncture drainage. Obviously, this treatment was unsuccessful. Hepatectomy and cholecystectomy were performed one month after the puncture. Postoperative pathologic examination revealed carcinosarcoma of the gallbladder, and the resected specimen contained two tumor components. One month after surgery, the patient's tumor recurred in situ and started to compress the duodenum, resulting in duodenal obstruction and bleeding. The treatment was not effective. The patient died of gastrointestinal hemorrhage and hypovolemic shock.

CONCLUSION

Carcinosarcoma of the gallbladder is a rare malignant tumor that is easily misdiagnosed preoperatively and has a poor prognosis.

Odontogenic Carcinosarcoma: Clinicopathologic and Molecular Features of Three Cases, a Literature Review and Nomenclature Proposal

BACKGROUND

Odontogenic carcinosarcoma (OCS) is a rare odontogenic malignancy with limited characterization and unexplored molecular features. We report clinicopathologic and molecular findings in 3 additional OCS and review the literature.

METHODS

3 OCS (5.1%) were identified among 59 malignant odontogenic tumors (in our archives from 1992 to 2022). Clinical, radiologic, histopathologic, immunophenotypic, and molecular findings were reviewed. Data from prior case reports and systematic or non-systematic reviews were extracted for analysis.

RESULTS

Three mandibular OCS (age range: 66 to 72 years; 1 male, 2 females) were identified. Case 1 had novel clear-cell morphology, multiple recurrences, and a lethal outcome 28 months after resection. EWSR1 rearrangements were negative, but the tumor showed focal nuclear β-catenin and strong LEF-1 immunoreactivity. Case 2 demonstrated ameloblastic and sclerosing features and encased the inferior alveolar nerve; the patient was disease-free 22 months after resection with adjuvant chemoradiation therapy. LEF-1 was again strongly positive, and next-generation sequencing demonstrated 9p region-(CDKN2A, CDKN2B) copy number loss, and 12q region-(MDM2, CDK4) copy number gain. Case 3 showed clear-cell and markedly sclerosing features; no follow-up information was available. Literature review along with the current cases yielded 20 cases. OCS showed a male predilection (1.5:1), mandibular predominance (80%, typically posterior), and a bimodal age distribution (modes: 27.7 years, 62.7 years). OCS presented as masses (100%), often with pain (55%), and paresthesia (45%). Tumors were typically radiolucent (88.9%), with bone destruction (61.1%), and/or tooth effacement (27.8%). Preoperative biopsy was sensitive for malignancy (85.7%). At least 45% show evidence for a precursor lesion. 3-year DSS and DFS were 58% and 35%, respectively. Regional and distant (usually lung) metastatic rates were 25% and 31.3%, respectively. Increased mitotic rates and presence of tumor necrosis trended toward worse DSS and DFS.

CONCLUSION

OCS is a rare but aggressive malignancy, often arising from precursor tumors and may represent a terminal phenotype rather than a distinct entity. We describe novel clear-cell and sclerosing morphologies. Wnt pathway alterations appear important. Mitotic rates and necrosis may be adverse prognosticators. In keeping with nomenclature trends in other sites, OCS may be more appropriately designated as "biphasic sarcomatoid odontogenic carcinomas."

Comprehensive analyses of intraoral spindle cell carcinoma: A rare disease entity revisited

OBJECTIVE

The present study was aimed to comprehensively characterize the epidemiological, clinicopathological characteristics, treatments, and prognosis of intraoral spindle cell carcinoma (SpCC).

MATERIALS AND METHODS

Patients diagnosed with intraoral SpCC at our institution in the past 15 years (2005-2019) were screened from inpatient disease registry. All relevant data concerning patients with intraoral SpCC were retrieved. Previous reports about intraoral SpCC with adequate clinicopathological data in both English literature and Chinese literature were collected. Eligible cases were further reviewed and pooled for statistical analyses.

RESULTS

Six patients (5 females and 1 male; average age: 59 years) with intraoral SpCC were histopathologically diagnosed and surgically treated at our institution. The literature review identified another 63 published cases from 34 articles. Most cases were presented in the fifth to seventh decade of life with a male preponderance. Gingiva (23/69, 33.3%) was the most common site followed by the tongue (19/69, 27.5%) and buccal mucosa (8/69, 11.6%). Complete surgical ablation remains the primary treatment option. Tumor size, pathological grades, cervical node metastasis, and distant metastasis were significantly associated with reduced survival.

CONCLUSIONS

Intraoral SpCC is an uncommon and aggressive malignancy with dismal prognosis. Much attention and effort are needed to characterize this rare entity and improve its clinical outcomes.

Whole-Process Treatment of Combined Small Cell Lung Cancer Initially Diagnosed as "Lung Squamous Cell Carcinoma": A Case Report and Review of the Literature

The rarity and complexity of histology lead to the low diagnosis rate and high misdiagnosis rate of combined small cell lung cancer (C-SCLC). Nowadays, C-SCLC has no commonly recommended therapeutic regimen, mainly conforming to SCLC treatment. Here, we report a patient initially diagnosed as IIIA "lung squamous cell carcinoma" by a small specimen. Radical resection was achieved after neoadjuvant immunochemotherapy, and the final surgical pathology was C-SCLC containing three different histological components. Moreover, in the literature review, we explored the therapeutic effect of neoadjuvant immunotherapy in C-SCLC, expounded the therapeutic conflicts among heterogeneous components, and analyzed the pathology complexity at the tissue, cell, and molecule levels in-depth, including possible genetic characteristics, origin, and evolution by next-generation sequencing (NGS).

A case of primary hepatic mixed neuroendocrine-non-neuroendocrine tumor (MiNEN) associated with gallbladder carcinosarcoma

A woman in her seventies visited our hospital because of abdominal pain. Multiple hepatic tumors were detected and a liver biopsy revealed mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN), which was composed of cholangiocellular carcinoma and neuroendocrine tumor (NET). Diagnostic imaging ruled out primary malignancies other than the liver and identified that the tumor originated from the liver. Because a predominant and aggressive part of the tumor was considered to be cholangiocellular carcinoma, gemcitabine and S-1 were used as first-line treatment. After the treatment, octreotide acetate was administered for the NET component, followed by transcatheter arterial embolization. Subsequently, her gallbladder (GB) rapidly swelled with biliary tract obstruction, and cholecystectomy revealed carcinosarcoma of the GB. She is still undergoing treatment at 44 months after diagnosis. Herein we report this case of primary hepatic MiNEN consisting of cholangiocarcinoma and NET, followed by GB carcinosarcoma. This is the first case illustrating that a multidisciplinary treatment approach for MiNEN accompanied with carcinosarcoma, involving assessment and treatment targeting the most aggressive component, can result in a long survival time.

The characteristic of tumor immune microenvironment in pulmonary carcinosarcoma

Pulmonary carcinosarcoma (PCS) is a rare but aggressive neoplasm, due to late diagnosis and early metastasis. Surgery combined with radiotherapy is a standard treatment. However, PCS features an easy relapse after surgery resection and resistance to chemotherapy and radiotherapy. Tumor immune microenvironment reflects tumor immunophenotyping and affects immunotherapy efficiency. This review summarized current studies on the characteristic of tumor immune microenvironment in PCS and discussed the potential of immunotherapy combined with other regimes strategy as a candidate for treatments in PCS.

Clinicopathologic features and genomic analysis of pulmonary blastomatoid carcinosarcoma

BACKGROUND

This study was designed to investigate the clinicopathologic features of pulmonary blastomatoid carcinosarcoma and explore the genomic profiles of epithelial and mesenchymal components in this tumor.

METHODS

Three cases of pulmonary blastomatoid carcinosarcoma were enrolled in this study. Clinicopathologic information and prognostic data were retrospectively reviewed. Diagnostic immunohistochemistry was performed. The epithelial and mesenchymal components were microdissected to investigate the genomic profiles by performing capture-based targeted next generation sequencing.

RESULTS

The epithelial components in patient one consisted of low-grade and high-grade fetal lung adenocarcinoma. Low-grade epithelial cells showed nuclear expression of β-catenin and missense mutation of CTNNB1. The epithelial components in another two patients consisted of high-grade fetal lung adenocarcinoma/enteric adenocarcinoma. The epithelial cells showed membrane staining of β-catenin and harbored no mutation of CTNNB1. The mesenchymal components in all three tumors were composed of primitive round/spindle cells without definite differentiation and showed cytoplasmic dot positive of β-catenin and no corresponding mutation. Within a tumor, both components exhibited relatively comparable molecular profile. In patient one, 4 mutations: RB1, FAT3, PTCH1 and LRP1B were shared by both epithelial and mesenchymal components. Epithelial component had additional mutations in BCOR, CTNNB1, CTCF, FAT1 and DICER1. In patient two, 12 mutations were shared. The epithelial component had BRCA2 mutation and the mesenchymal had mutations in CREBBP, ALK, DNMT3A, ASXL2, MYCN and RICTOR. Patient three had 6 shared mutations. The epithelial component had an additional mutation in KAT6A and the mesenchymal had an additional mutation in APC. Collectively, we observed heterogeneity between epithelial and mesenchymal components of the same tumor.

CONCLUSIONS

Blastomatoid carcinosarcoma showed characteristic morphology and immunophenotype. Parallel detection of genetic abnormalities in epithelial and mesenchymal components could provide further evidence for tumor differentiation, molecular targeting and differential diagnosis.

The EMT transcription factor, Twist1, as a novel therapeutic target for pulmonary sarcomatoid carcinomas

Pulmonary sarcomatoid carcinomas (PSCs) are a rare subtype of non‑small‑cell lung cancer and are typically biphasic neoplasms. No effective treatment for PSCs is currently available in clinical practice. The expression of the epithelial‑mesenchymal transition (EMT) transcription factors, Twist1, Slug and Snail, as well as the EMT phenotype and vasculogenic mimicry (VM) were analysed in 41 PSC and 79 pulmonary squamous carcinoma (PSCC) samples. Compared with the PSCCs, the PSCs exhibited an EMT phenotype and VM, and they also exhibited an increased expression of the Twist1, Slug, Snail and VM markers. Twist1 expression was associated with metastasis and TNM stage. Twist1‑positive patients exhibited a poorer prognosis for overall survival (OS) than those with Twist1‑negative PSCs. Transforming growth factor β1 (TGFβ1) was used to induce an EMT transition in a PSCC cell line. SK‑MES‑1 cells treated with TGFβ1 exhibited an increased expression of Twist1. The EMT phenotype, VM and increased migratory and invasive abilities were induced following TGFβ1 treatment. Importantly, in cells treated with TGFβ1, the EMT phenotype was reversed, VM marker expression was decreased, and the migratory and invasive ability of the PSCC cell line was decreased following Twist1 knockdown. Collectively, this study provides a new perspective of Twist1 in the aggressiveness of PSCs. The identification of Twist1 as an independent marker of poor prognoses may lead to the development of novel strategies for improving the treatment of patients with PSC.

Approaches to Tumor Classification in Pulmonary Sarcomatoid Carcinoma

Pulmonary sarcomatoid carcinoma (PSC) is a heterogeneous category of primary lung cancer accounting from 0.3% to 3% of all primary lung malignancies. According to the most recent 2015 World Health Organization (WHO) classification, PSC includes several different variants of malignant epithelial tumors (carcinomas) histologically mimicking sarcomas showing or entirely lacking a conventional component of non-small cell lung cancer (NSCLC). Thus, this rare subheading of lung neoplasms includes pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, pulmonary blastoma, and carcinosarcoma. A diagnosis of PSC may be suspected on small biopsy or cytology, but commonly requires a surgical resection to reach a conclusive definition. The majority of patients with PSC consists of elderly, smoking men with a large, peripheral mass characterized by well-defined margins. However, presentation with a central, polypoid endobronchial lesion is well-documented, particularly in pleomorphic carcinoma and carcinosarcoma showing a squamous cell carcinoma component. As expected, PSC may pose diagnostic problems and immunohistochemistry is largely used when pathologists deal these tumors in routine practice. Indeed, PSC tends to overexpress molecules associated with the epithelial-to-mesenchymal transition, such as vimentin, but the panel of immunostains also includes epithelial markers (cytokeratins, EMA), TTF-1, p40 and negative markers (e.g., melanocytic, mesothelial and sarcoma-related primary antibodies). Although rare, PSC has increased their interest among oncologist community for different reasons: a. identification of the epithelial-to-mesenchymal phenomenon as a major mechanism of secondary resistance to tyrosine kinase inhibitors; b. over-expression of PD-L1 and effective treatment with immunotherapy; c. identification of c-MET exon 14 skipping mutation representing an effective target to crizotinib and other specific inhibitors. In this review, the feasibility of the diagnosis of PSC, its differential diagnosis and novel molecular findings characterizing this group of lung tumor are discussed.

A rare presentation of carcinosarcoma of the bone in a young female; response with gemcitabine and docetaxel

Background

Sarcomatoid carcinoma, or carcinosarcoma, is a neoplasm that contains both sarcomatous and carcinomatous elements. It is an extremely rare cancer most often arising from visceral organs. Here we report the seventh documented de novo case of carcinosarcoma of the bone, in a young female who showed initial clinical improvement with gemcitabine and docetaxel.

Case presentation

A 36-year-old Caucasian female presented with diffuse musculoskeletal pain that had progressed from her shoulder to her back, arm, and knee over 6 months. Imaging revealed diffuse sclerotic lesions of bilateral humeral heads, iliac and ischial bones, and thoracic and lumbar spine. Histopathologic examination of biopsies from the T9 vertebra and left femur showed mainly sarcomatous spindle cells with focal osteoid production. Immunostaining showed the cells to be OSCAR cytokeratin, patchy positive for pankeratin, and negative for CK7, GATA3, S100, SOX10, CD99, EMA, AE1/AE3, and HMW keratin indicative of an epithelial origin. After thorough clinical correlation, sarcomatoid carcinoma of a visceral organ was excluded and the diagnosis of primary sarcomatoid carcinoma of the bone was ultimately favored. She received chemotherapy with gemcitabine and docetaxel, and showed improvement at 6 months but ultimately passed 1 year post diagnosis.

Conclusions

Primary carcinosarcoma of the bone is an extremely rare malignancy. Early diagnosis is crucial as localized disease may be curable with resection. As shown in this case, combination chemotherapy with gemcitabine and docetaxel is a potential option in patients with unresectable or metastatic disease.

Pulmonary sarcomatoid carcinoma: an analysis of a rare cancer from the Surveillance, Epidemiology, and End Results database

OBJECTIVES

Pulmonary sarcomatoid carcinoma (PSC) is a rare malignant neoplasm that accounts for a small percentage of non-small-cell lung carcinoma (NSCLC). At least 10% of PSCs has a spindle and/or giant cell component, which is often associated with a poor prognosis. We reviewed the Surveillance, Epidemiology, and End Results (SEER) database for the clinicopathological characteristics and surgical outcomes of PSCs.

METHODS

The SEER database (1973-2013) was queried for PSC. A comparison between PSC and other NSCLC patients was performed. Cox regression for overall survival (OS) and logistic regression for node-positive predictors were performed. A propensity-matched (1:2) analysis (including age, gender, grade and stage) among surgically treated cases was done to compare OS in PSC versus other NSCLCs.

RESULTS

A total of 955 899 NSCLC patients were identified; of these, 4987 patients had been diagnosed with PSC (0.52%). Men represented 60.9% of cases, with a median age of 68 years. The median size of the tumour was 5 cm and 3.5 cm in PSCs and NSCLCs, respectively (P < 0.001). PSC patients had significantly less Stage I, more high-grade tumours, advanced T stage, N+ disease and M1 disease (P < 0.001). In the PSC cohort, the most significant predictor of N+ disease on multivariate analysis was advanced T stage (P < 0.001). Predictors of OS in Stages I/II PSC on multivariate analysis were advanced age [P < 0.001, hazard ratio (HR) = 1.03], male gender (P = 0.024, HR = 1.25), carcinosarcoma (P = 0.002, HR = 1.76), grade (P = 0.033, HR = 1.81), T stage (P = 0.003, HR = 1.75), N status (P = 0.001, HR = 1.90) and surgical resection (P < 0.001, HR = 0.58). Among matched surgically resected cohorts, a poorer prognosis for OS was evident in PSCs in early stages (I/II) than in other NSCLCs (P = 0.009).

CONCLUSIONS

PSC patients present with more advanced stage and with worse survival outcomes than other NSCLC patients. While surgical resection conveys a survival advantage in PSC, this group represents a population at a high risk for relapse and should be evaluated for novel adjuvant therapies.

Pulmonary carcinosarcoma showing an obvious response to pazopanib: a case report

BACKGROUND

Pulmonary carcinosarcoma (PCS) is a rare primary lung malignancy and has a poor prognosis among lung tumor histological subtypes. However, an appropriate treatment strategy has not been developed for unresectable PCS.

CASE PRESENTATION

A 65-year-old man who was diagnosed with PCS was treated by surgical removal of the primary lung lesion, followed by six cycles of adjuvant chemotherapy with cisplatin plus irinotecan. Following the chemotherapy, he experienced a relapse with brain metastasis, which induced the rapid onset of left leg paralysis. Radical surgical resection and stereotactic radiosurgery to the resection cavity were performed. However, meningeal dissemination and new lung metastases occurred after a year and half. To control these multiple metastatic lesions, the patient was treated with the multiple kinase inhibitor pazopanib. No change was observed in the meningeal dissemination, while the metastatic lung lesions were prominently reduced in size following treatment with pazopanib. Consequently, the patient showed a partial response to pazopanib treatment, although the dose of pazopanib was reduced by half as a result of thrombocytopenia.

CONCLUSION

This is the first report of metastatic PCS showing an evident therapeutic response to tumor-targeted therapy. We suggest that pazopanib may be a therapeutic option for patients with metastatic PCS.

Pulmonary Sarcomatoid Carcinomas: A Review

Pulmonary sarcomatoid carcinomas belong to a group of neoplasms that remain incompletely understood. They are rare tumors of the bronchopulmonary system that incorporate a wide range of neoplasms that by definition contain a sarcomatoid component characterized by spindle or giant cells. Such classification has led to a heterogenous tumor category that includes neoplasms with different clinical, morphologic, and prognostic features. To date, the histopathologic diagnosis of pulmonary sarcomatoid carcinomas does not require the use of ancillary testing and is based on light microscopic criteria alone. However, with recent advances in immunohistochemical and molecular methods, it is becoming increasingly clear that pulmonary sarcomatoid carcinomas represent poorly differentiated or "dedifferentiated" variants of conventional non-small cell carcinomas with similar immunophenotype and molecular signatures. This review summarizes the latest insights and concepts of these unusual tumors and outlines future directions with emphasis on tumor classification and patient management.

Immunohistochemical analysis of NANOG expression and epithelial-mesenchymal transition in pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid carcinomas (PSCs) are defined as a group of poorly differentiated non-small cell lung cancers that demonstrate sarcoma-like differentiation. The mechanism of mesenchymal differentiation in PSC is epithelial-mesenchymal transition (EMT). The expression of homeobox protein NANOG (NANOG), which regulates the pluripotency of embryonic stem cells, is associated with the EMT process. Therefore, the present study aimed to assess the expression level of NANOG and the status of the EMT process in PSC. The data of patients with PSC were retrospectively reviewed and immunohistochemical analyses were performed on patient samples to examine the expression of NANOG and EMT-associated proteins. The comparator group included randomly selected patients with matched clinicopathological characteristics who had pulmonary adenocarcinoma (PA). In the present study, 12 patients with PSC (4 females and 8 males) were enrolled; their median age was 65 years (range, 36-79 years), and the number of patients with stage IB, IIB, IIIA, IIIB and IV disease were 1, 1, 1, 1 and 8, respectively. The immunoreactive score (IRS) for E-cadherin was significantly lower in the PSC group compared with the PA group (P<0.0001), whereas the IRS for vimentin was significantly higher in the PSC group compared with the PA group (P<0.0001). However, the IRS for NANOG was significantly decreased in the PSC group compared with the PA group (P<0.0001), which suggests that NANOG does not serve an essential role in EMT in PSC. In addition, the overall survival of patients with PSC was significantly lower compared with that of patients with PA (median survival time, 7.0 vs. 35.6 months, respectively; P=0.0256). However, no significant difference was observed in the OS of patients who expressed low compared with high levels of NANOG (P=0.4416). In conclusion, it was clearly demonstrated that cytoplasmic NANOG expression was significantly lower in PSC compared with PA, and that the EMT process in PSC was accelerated, compared with that in PA.

The 2015 World Health Organization Classification of Lung Tumors: Impact of Genetic, Clinical and Radiologic Advances Since the 2004 Classification

The 2015 World Health Organization (WHO) Classification of Tumors of the Lung, Pleura, Thymus and Heart has just been published with numerous important changes from the 2004 WHO classification. The most significant changes in this edition involve (1) use of immunohistochemistry throughout the classification, (2) a new emphasis on genetic studies, in particular, integration of molecular testing to help personalize treatment strategies for advanced lung cancer patients, (3) a new classification for small biopsies and cytology similar to that proposed in the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (4) a completely different approach to lung adenocarcinoma as proposed by the 2011 Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification, (5) restricting the diagnosis of large cell carcinoma only to resected tumors that lack any clear morphologic or immunohistochemical differentiation with reclassification of the remaining former large cell carcinoma subtypes into different categories, (6) reclassifying squamous cell carcinomas into keratinizing, nonkeratinizing, and basaloid subtypes with the nonkeratinizing tumors requiring immunohistochemistry proof of squamous differentiation, (7) grouping of neuroendocrine tumors together in one category, (8) adding NUT carcinoma, (9) changing the term sclerosing hemangioma to sclerosing pneumocytoma, (10) changing the name hamartoma to "pulmonary hamartoma," (11) creating a group of PEComatous tumors that include (a) lymphangioleiomyomatosis, (b) PEComa, benign (with clear cell tumor as a variant) and

Anaplastic Lymphoma Kinase (ALK) Rearrangement-positive Lung Cancer with Transformation to Pleomorphic Carcinoma

A 55-year-old woman was diagnosed with a tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK) rearrangement-positive lung adenocarcinoma and treated with chemotherapy consisting of crizotinib, a tyrosine kinase inhibitor of ALK, as second-line chemotherapy. However, the size of the metastatic adrenal lesion increased, and the patient died due to multiple organ failure. An autopsy report revealed that the metastatic lesion of the adrenal tumor was ALK rearrangement-positive pleomorphic carcinoma. The epithelial-mesenchymal transition (EMT) marker vimentin was immunohistochemically positive in both the lung and adrenal lesions. The present case report suggests the possibility of transformation into pleomorphic carcinoma as a result of EMT in patients with ALK rearrangement-positive lung cancer.

Clinicopathological analysis of pleomorphic carcinoma of the lung: diffuse ZEB1 expression predicts poor survival

OBJECTIVES

Pleomorphic carcinoma (PC) of the lung is a rare epithelial tumor. The clinicopathological characteristics and prognostic factors of PC are controversial. The information on the ZEB1 gene, which crucially impacts survival of patients with other malignant tumors, is limited for PC.

MATERIALS AND METHODS

Clinicopathological characteristics of 62 patients with PC were investigated in this study. Associations between immunohistochemical expression of ZEB1 and clinical factors, including patient prognosis, were examined. The patient population consisted of 51 (82.2%) men and 11 (17.8%) women, with a mean age of 65.5 years (range, 31-81 years).

RESULTS

The overall survival rate of the 42 patients, for whom follow-up was available, was 68.3% at 5 years. Using TNM criteria, 7 (11.3%), 11 (17.7%), 3 (4.8%), 21 (33.8%), 15 (24.2%), 2 (3.2%), and 3 (4.8%) patients were classified under pathological stage IA, IB, IIA, IIB, IIIA, IIIB and IV carcinomas, respectively. Fifteen (24.1%) patients had tumors consisting entirely of spindle and giant cells (PC component). The other 47 (75.8%) cancers contained additional carcinoma components (i.e., adenocarcinoma (34/62, 54.8%), squamous cell carcinoma (7/62, 11.3%), adenosquamous carcinoma (4/62, 6.5%) and large cell carcinoma (2/62, 3.2%)). Four of 7 (57.1%) stage IA (<20mm) tumors consisted only of spindle and giant cells. ZEB1 expression was observed only in the PC component. Diffuse expression of ZEB1, was defined as positive nuclear staining in ≥75% of cancer cells, and was found in the PC component in 12 patients. Multivariate analysis revealed that lymph node metastasis, pleural invasion, and diffuse ZEB1 expression in the PC component predicted poorer disease-specific survival (p=0.007, 0.022, and 0.016, respectively).

CONCLUSION

This is the first report to indicate that ZEB1 may be used as an immunohistochemical prognosticator of PC, which may be useful for histological assessment of PC in biopsy and surgical specimens.

The pivotal role of pathology in the management of lung cancer

The last decade has seen significant advances in our understanding of lung cancer biology and management. Identification of key driver events in lung carcinogenesis has contributed to the development of targeted lung cancer therapies, heralding the era of personalised medicine for lung cancer. As a result, histological subtyping and molecular testing has become of paramount importance, placing increasing demands on often small diagnostic specimens. This has triggered the review and development of the first structured classification of lung cancer in small biopsy/cytology specimens and a new classification of lung adenocarcinoma from the IASLC/ATS/ERS. These have enhanced the clinical relevance of pathological diagnosis, and emphasise the role of the modern surgical pathologist as an integral member of the multidisciplinary team, playing a crucial role in clinical trials and determining appropriate and timely management for patients with lung cancer.

ARF inhibits the growth and malignant progression of non-small-cell lung carcinoma

Non-small-cell lung carcinoma (NSCLC) is among the deadliest of human cancers. The CDKN2A locus, which houses the INK4a and ARF tumor suppressor genes, is frequently altered in NSCLC. However, the specific role of ARF in pulmonary tumorigenesis remains unclear. KRAS and other oncogenes induce the expression of ARF, thus stabilizing p53 activity and arresting cell proliferation. To address the role of ARF in Kras-driven NSCLC, we compared the susceptibility of NIH/Ola strain wild-type and Arf-knockout mice to urethane-induced lung carcinogenesis. Lung tumor size, malignancy and associated morbidity were significantly increased in Arf(-/-) compared with Arf(+/+) animals at 25 weeks after induction. Pulmonary tumors from Arf-knockout mice exhibited increased cell proliferation and DNA damage compared with wild-type mice. A subgroup of tumors in Arf(-/-) animals presented as dedifferentiated and metastatic, with many characteristics of pulmonary sarcomatoid carcinoma, a neoplasm previously undocumented in mouse models. Our finding of a role for ARF in NSCLC is consistent with the observation that benign adenomas from Arf(+/+) mice robustly expressed ARF, while ARF expression was markedly reduced in malignant adenocarcinomas. ARF expression also frequently colocalized with the expression of p21(CIP1), a transcriptional target of p53, arguing that ARF induces the p53 checkpoint to arrest cell proliferation in vivo. Taken together, these findings demonstrate that induction of ARF is an early response in lung tumorigenesis that mounts a strong barrier against tumor growth and malignant progression.

Gallbladder carcinosarcoma accompanied with bile duct tumor thrombi: A case report

Gallbladder carcinosarcoma is one of the rarest subsets of gallbladder malignancies. The first case of carcinosarcoma of the gallbladder was reported in 1907. To date, <100 cases have been reported in the English literature. The present study reports a case of gallbladder carcinosarcoma accompanied with tumor thrombi, presenting as a soft tissue mass in the common bile duct and resulting in the obstruction and inflammation of the biliary tract. Initially, the patient was diagnosed with a gallbladder tumor and choledocholithiasis. No cases of carcinosarcoma of the gallbladder accompanied with bile duct tumor thrombus formation have been reported to date. A cholecystectomy with liver segmentectomy (S4a+S5) and a lymph node dissection were performed. The presence of a tumor thrombus in the common bile duct was confirmed by analysis of a frozen section during surgery. Resection of the extrahepatic bile duct and Roux-en-Y type hepatic cholangiojejunostomy were also performed. In addition, the gallbladder carcinosarcoma was observed to produce α-fetoprotein. The patient underwent an uneventful post-operative recovery and, to date, no clinical or radiological evidence of disease recurrence or metastasis has been identified. Carcinosarcoma of the gallbladder accompanied with tumor thrombi is extremely rare. Tumor thrombi in the common bile duct may easily be misdiagnosed as choledocholithiasis. The treatment and prognosis of gallbladder carcinosarcoma is similar to that of gallbladder carcinoma.

Emerging evidence of epithelial-to-mesenchymal transition in lung carcinogenesis

The epithelial-to-mesenchymal transition (EMT) is a developmental programme that regulates embryonic morphogenesis and involves significant morphological and molecular changes in cells. Experimental models have revealed that EMT also contributes to various malignant features of cancer cells, including motile, invasive, anti-apoptotic and stem-like phenotypes. Clinically, correlative studies have indicated that mesenchymal-like features of tumour cells are associated with poor tumour differentiation as well as worse patient prognosis. Nevertheless, due to its transitory nature, demonstration of an actual occurrence of EMT during human carcinogenesis is challenging, and most of the evidence to date has been limited to breast and colorectal cancers. However, recent studies suggest that EMT may occur during lung cancer development, although such evidence is still limited. We propose three approaches for obtaining direct evidence of EMT in human cancers and use these criteria to review the available data. We suggest that multiple intrinsic and extrinsic factors cooperatively induce EMT in lung cancer. Intrinsic factors include oncogenic genetic changes such as mutant K-RAS. Extrinsic factors are associated with a tumour microenvironment that is inflammatory and hypoxic. The induction of EMT is primarily mediated by various EMT-inducing transcription factors that suppress E-cadherin expression, including SLUG and ZEB1. miR-200 family expression can reverse EMT by suppressing EMT- inducing transcription factors. Obviously, more data demonstrating the clinical relevance of EMT in lung cancer are required, and further elucidation of how EMT is regulated in lung cancer will enable us to develop novel therapeutics that specifically target molecules with critical roles in EMT.

Insights into cancer metastasis from a clinicopathologic perspective: Epithelial-Mesenchymal Transition is not a necessary step

Epithelial-mesenchymal transition (EMT) has been implicated as the critical event initiating cancer invasion and metastasis. After disseminating through the circulation, the malignant cells have been proposed to undergo subsequent mesenchymal-epithelial transition (MET) to form secondary tumors. However, strong evidence from human tumor specimens for this paradigm is lacking. In carcinomas, cancers derived from epithelial tissues, epithelial morphology and gene expression are always retained to some degree. While mesenchymal transdifferentiation may be involved in the pathogenesis of carcinosarcomas, even in these neoplasms, as well as in germ cell tumors capable of multilineage differentiation, the mesenchymal phenotype does not facilitate metastatic progression. Indeed, most cancers invade and travel through lymphatic and blood vessels via cohesive epithelial migration, rather than going through the EMT-MET sequence. EMT gene expression is also consistently associated with high histologic grade and while the transcription factors, Snail, Slug and Twist have traditionally been thought of as inducers of EMT, under certain conditions, they also mediate dedifferentiation and maintenance of the stem cell state. In various malignancies, including basal-like breast cancer and colorectal cancer, the genetically unstable, undifferentiated phenotype predicts early metastatic spread and poor prognosis. This article discusses some of the controversies surrounding differentiation and metastasis from a clinicopathologic perspective and presents evidence that the epithelial phenotype is maintained throughout the process of cancer metastasis.

Blastomatoid pulmonary carcinosarcoma: report of a case with a review of the literature

BACKGROUND

Pulmonary carcinosarcoma is a biphasic tumour with an unfavourable prognosis. The differential diagnosis includes pulmonary blastoma and is often challenging.

CASE PRESENTATION

We here describe a case of blastomatoid pulmonary carcinosarcoma in a 58-year-old patient, who underwent surgical resection. Histopathological examination revealed immature glandular epithelium resembling high-grade fetal adenocarcinoma expressing epithelial markers and membranous beta-catenin, and blastomatoid spindle cells with partial rhabdomyosarcoma-like differentiation. Both elements expressed p53, MDM2, and cyclin-dependent kinase 4 (CDK4), but not thyroid-transcription factor 1 (TTF-1). Mutation analysis of KRAS, EGFR, and beta-catenin revealed no mutations. Comparative genomic hybridization detected +1q, +6p, +6q24qter, +8q, +11q12q14, +11q23qter, +12q12q21, +12q24qter, +17q, +20q, -5q14q23, -9p13pter, -13q21q21, and amplifications at 12q14q21, 15q24qter, 20q11q12.

CONCLUSION

The observed molecular and cytogenetic findings may provide additional tools for the differential diagnosis of biphasic pulmonary neoplasms. Furthermore, TP53, MDM2, CDK4, and PTPN1 may be involved in tumourigenesis.

Epithelial-mesenchymal transition in pulmonary carcinosarcoma: case report and literature review

Pulmonary carcinosarcoma is a rare and aggressive neoplasm that has both epithelial and mesenchymal components. We report on a 63-year-old woman who was found to have a right upper-lobe pulmonary carcinosarcoma with metastases to the liver and gastric fundus. There are currently no published guidelines on the treatment of pulmonary sarcomatoid carcinomas. However, with our expanding knowledge of cancer metastasis, cases of carcinosarcoma illustrate our current understanding of epithelial-mesenchymal transition in action. Here, we discuss the development and treatment of these biphasic tumors and the possible role of epithelial-mesenchymal transition.

Hypertrophic osteopathy associated with two pulmonary tumours and myocardial metastases in a dog: a case report

CASE HISTORY

A 16-year-old dog was presented to the University of Melbourne Veterinary Clinic and Hospital for dyspnoea and tachypnoea, which had been occurring over the previous 48 h prior to presentation.

CLINICAL FINDINGS

Physical examination findings included marked wheezing and inspiratory noises on thoracic auscultation. Diagnostic tests performed revealed a large pulmonary mass, the presence of hypertrophic osteopathy in the forelimbs and an abnormal myocardium. The patient continued to deteriorate while in hospital, and was euthanased at the owner's request. A post-mortem examination was carried out, which revealed the presence of two separate pulmonary masses, one of which was completely occluding the mainstem bronchus.

DIAGNOSIS

One tumour was histologically classified as an adenocarcinoma, the other as an extraskeletal osteosarcoma. The osteosarcoma had metastasised to the myocardium, spleen and kidneys. The forelimb changes were consistent with hypertrophic osteopathy.

CLINICAL RELEVANCE

This is the first reported case of two separate pulmonary masses in a dog, one of which metastasised to the myocardium. Hypertrophic osteopathy is a common pathological condition associated with a broad spectrum of diseases. The aim of this case report is to highlight the condition and remind clinicians of its relatively common incidence, as well as to prompt clinicians to look for underlying pathology. The current understanding of the pathophysiology of hypertrophic osteopathy is also discussed.

Pulmonary carcinosarcoma with an osteosarcomatous component

Pulmonary carcinosarcoma is a rare disease entity defined as a neoplasm, which has biphasic features consisting of both epithelial and sarcomatous components. It has been reported that the most frequent epithelial component is squamous cell carcinoma, while the most frequent sarcomatous component is rhabdomyosarcoma. Pulmonary carcinosarcomas with osteosarcoma components are even rarer. We report a case of a potentially curative resection for carcinosarcoma with an osteosarcoma component. Thoracic surgeons should be aware of this rare tumor when lung tumors with ossification are encountered.

Adrenocortical neoplasia: evolving concepts in tumorigenesis with an emphasis on adrenal cortical carcinoma variants

Adrenocortical carcinoma (ACC) is a rare, heterogeneous malignancy with a poor prognosis. According to WHO classification 2004, ACC variants include oncocytic ACCs, myxoid ACCs and ACCs with sarcomatous areas. Herein, we provide a comprehensive review of these rare subtypes of adrenocortical malignancy and emphasize their clinicopathological features with the aim of elucidating aspects of diagnostic categorization, differential diagnostics and biological behavior. The issue of current terminology, applied to biphasic tumors with pleomorphic, sarcomatous or sarcomatoid elements arising in adrenal cortex, is also discussed. We additionally present emerging evidence concerning the adrenal cortical tumorigenesis and the putative adenoma-carcinoma sequence as well.

Combined small-cell carcinoma of the lung with quadripartite differentiation of epithelial, neuroendocrine, skeletal muscle, and myofibroblastic type

The combined variant of small-cell lung carcinoma (SCLC) refers to the variable admixture of small cell and non-small cell carcinoma, whereas the association with sarcoma or sarcoma-like elements is exceedingly rare. A 76-year-old Caucasian man underwent right upper lobectomy with regional lymphadenectomy because of a symptomatic 7 cm-sized tumor mass. Formalin fixed-paraffin embedded material was used to highlight several differentiation cell lineages by means of immunohistochemistry, electron microscopy, and mutational assay. The tumor was discovered as being IIB stage (pT2b pN1(1/51) pM0) and featured biphasic appearance with close intermingling of SCLC (40%) and collagen-rich spindle cell sarcoma (60%). Epithelial (cytokeratins, TTF-1), neural (neurofilaments, GFAP), endocrine (chromogranin, synaptophysin, CD56), and skeletal muscle (desmin, sarcomeric actin, myogenin) markers were variably co-expressed by SCLC elements, whereas mesenchymal (vimentin), smooth muscle (actin, myosin, H-caldesmon, calponin), fibroblastic (CD10), and, more focally, skeletal muscle (desmin, sarcomeric actin and myogenin) markers were highlighted in the spindle cell sarcoma elements. TP53 codon V274F mutation in exon 8 was shared by either cell component. After undergoing adjuvant chemotherapy, the patient is currently alive and well at the 40-month follow-up. To the best of our knowledge, this is the first report of combined SCLC with quadripartite differentiation of epithelial, neuroendocrine, skeletal muscle, and myofibroblastic type, somewhere at the level of the same individual tumor cells. This tumor had probably derived for clonal evolution of a p53-mutated common ancestor lesion.

Sarcomatoid neoplasms of the lung and pleura

Sarcomatoid neoplasms of the lung and pleura are rare tumors that present a complex differential diagnosis, making them challenging for surgical pathologists. In the lung, the main tumors are the sarcomatoid carcinomas, including pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. They are characterized by histologic heterogeneity; molecular data support their origin from a pluripotent stem cell that undergoes neoplastic transformation with divergent epithelial and sarcomatous differentiation. Diagnosis is difficult in small biopsy specimens and typically requires a resection specimen. Despite the presence of sarcomatoid features, these tumors are classified as lung carcinomas. Pulmonary blastomas must be distinguished from pleuropulmonary blastomas, which are a unique type of thoracic sarcoma typically occurring in young children. In the pleura, the main tumors to consider are the sarcomatoid and desmoplastic types of malignant mesothelioma, solitary fibrous tumor, and desmoid tumor. While light microscopy is sufficient to diagnose most of these tumors, immunohistochemistry can be useful in selected settings. In particular, it can aid to confirm epithelial differentiation in spindle cell carcinomas and the presence of rhabdomyosarcoma in sarcomatoid carcinomas, mesotheliomas, or pleuropulmonary blastomas. For sarcomatoid and desmoplastic mesothelioma, keratin is the most useful stain because it can highlight invasive growth and mesothelial markers are positive in only the minority of cases. Clinical and radiologic correlation is needed to separate some pleomorphic carcinomas with pleural involvement from sarcomatoid malignant mesothelioma, since these poorly differentiated tumors may not express the usual immunohistochemical markers for carcinoma or mesothelioma.

Carcinosarcoma of the Sigmoid Colon: Report of a Case

Our case was a 65-year-old male, with the chief complaints of diarrhea and abdominal distention. Three years earlier, the patient had undergone transcatheter arterial embolization and radiofrequency treatment based on a diagnosis of hepatocellular carcinoma due to hepatitis B by another doctor. In October 2007, the patient developed diarrhea and increased abdominal distention. In December, CT examination conducted by the previous doctor revealed a 20-cm tumor within the pelvis. The patient was diagnosed with sigmoid colon cancer based on barium enema examination using gastrografin, and was introduced to our hospital for treatment. He was diagnosed with low-differentiated carcinoma by biopsy of the colon during endoscopy and underwent sigmoidectomy based on a diagnosis of sigmoid colon cancer. The tumor had infiltrated the bladder, and a tumorectomy was conducted through partially combined resection. The tumor was a huge lesion occupying the inside of the lumen, and histopathological findings revealed that the tumor, the main part of which lay beneath the mucous membrane, had a transitional image composed of both spindle-shaped atypical cells and sarcomatoid shape. The result of immunostaining was CK7(+), CK20(-), AFP(-), and the patient was diagnosed as having carcinosarcoma of the colon. Carcinosarcoma of the colon is a malignant tumor with poor prognosis, and the mean survival period in past reports was approximately 6 months. The patient was treated with FOLFIRI+Bevacizumab therapy according to chemotherapy for colon cancer, but he was refractory to the therapy.

Epithelial-mesenchymal transition: a cancer researcher's conceptual friend and foe

Epithelial-mesenchymal transition (EMT) describes a series of rapid changes in cellular phenotype. During EMT, epithelial cells down-modulate cell-cell adhesion structures, alter their polarity, reorganize their cytoskeleton, and become isolated, motile, and resistant to anoikis. The term EMT is often applied to distinct biological events as if it were a single conserved process, but in fact EMT-related processes can vary in intensity from a transient loss of cell polarity to the total cellular reprogramming, as found by transcriptional analysis. Based on clinical observations, it is more appropriate in most cases to describe the emergence of an EMT-like phenotype during tumor progression. Although EMT implies complete trans-differentiation, EMT-like emphasizes the intermediary phenotype associated with tumor cell renewal and adaptation to specific microenvironments. Here, we categorize the various EMT-like phenotypes found in human carcinomas that, depending on the tumor type, may or not represent analogous stages in tumor progression. We based these categories on the global tumor phenotype. The tumor microenvironment, which is associated with stromal reactions, hypoxia, paucity of nutrients, impaired differentiation, and activation of various EMT-associated pathways, modulates overall tumor phenotype and leads to tumor heterogeneity.

Sarcomatoid carcinoma of the adrenal gland: A case report and review of literature

Reports about adrenocortical carcinomas (AC) mixed with sarcomatous areas are very rare. The terminology and pathogenesis of such biphasic tumors remain controversial. Herein, we report a case of sarcomatoid carcinoma of the adrenal gland in a 75-year-old woman who presented with left abdominal pain of one month's standing. The results of abdominal ultrasonography and computed tomography (CT) showed the presence of a large heterogeneous adrenal mass. A left adrenalectomy and complete splenectomy were performed. Histologically, the neoplasm showed areas of adrenocortical carcinoma and areas of sarcomatoid spindle cell proliferation. When examined immunohistochemically, the carcinomatous cells stained positively for S-100 protein, Melan-A protein, and neuron-specific enolase (NSE), and focally for vimentin and the cytokeratin marker MNF 116. Also, the carcinomatous cells were immunoreactive to the monoclonal antibody HMB-45. The sarcomatous component expressed vimentin, as well as other smooth and skeletal muscle markers. Liver metastases appeared 3 months postoperatively. Twelve months after removal of the primary tumor, the patient died of her disease. To the best of our knowledge, only seven cases of adrenal sarcomatoid carcinoma have been reported in the medical literature. We review the reported cases according to the 2004 classification of the World Health Organization (WHO) of lung tumors, and highlight the histogenesis, diagnosis, and clinical course of this very aggressive tumor.

Epithelial-mesenchymal transition: a cancer researcher's conceptual friend and foe

Epithelial-mesenchymal transition (EMT) describes a series of rapid changes in cellular phenotype. During EMT, epithelial cells down-modulate cell-cell adhesion structures, alter their polarity, reorganize their cytoskeleton, and become isolated, motile, and resistant to anoikis. The term EMT is often applied to distinct biological events as if it were a single conserved process, but in fact EMT-related processes can vary in intensity from a transient loss of cell polarity to the total cellular reprogramming, as found by transcriptional analysis. Based on clinical observations, it is more appropriate in most cases to describe the emergence of an EMT-like phenotype during tumor progression. Although EMT implies complete trans-differentiation, EMT-like emphasizes the intermediary phenotype associated with tumor cell renewal and adaptation to specific microenvironments. Here, we categorize the various EMT-like phenotypes found in human carcinomas that, depending on the tumor type, may or not represent analogous stages in tumor progression. We based these categories on the global tumor phenotype. The tumor microenvironment, which is associated with stromal reactions, hypoxia, paucity of nutrients, impaired differentiation, and activation of various EMT-associated pathways, modulates overall tumor phenotype and leads to tumor heterogeneity.

Review article: pulmonary sarcomatoid carcinomas: a practical overview

Pulmonary sarcomatoid carcinomas (PSCs) are currently defined as poorly differentiated non-small-cell carcinomas containing a component with sarcoma or sarcoma-like (spindle and/or giant cell) features. They consist of 5 major histological variants, namely pleomorphic carcinoma, spindle cell carcinoma, giant cell carcinoma, carcinosarcoma, and pulmonary blastoma. The segregation of PSCs into a distinct clinicopathologic entity seems justified on the basis of morphologic, behavioral, and genotypic/phenotypic attributes. As a group, PSCs generally run an aggressive clinical course and may cause major difficulties in the differential diagnosis with other primary and secondary malignancies of the lung. At present, PSCs are believed to represent a family of carcinomas "in transition," in which diverse pathways of clonal evolution account for histological differences of a common ancestor lesion. The sarcomatous or sarcomatoid component of these tumors is thought to derive from carcinoma cells during the progression of carcinogenesis through the activation of an epithelial-mesenchymal transition program leading to sarcomatous transformation or metaplasia (conversion paradigm). Conceivably, targeting the epithelial-mesenchymal transition program could become a valid therapeutic strategy for these life-threatening tumors, whose sensitivity to current medical manipulation is disappointing.

Primary carcinosarcoma of the liver: clinicopathologic features of 5 cases and a review of the literature

Carcinosarcoma of the liver is very rare worldwide. The terminology and pathogenesis of hepatic carcinosarcoma remain controversial issues. In this article, we studied the clinicopathologic features of 5 cases of hepatic carcinosarcomas (matching the World Health Organization definition), analyzed the clinical data, histologic and immunohistochemical (IHC) results, and discussed the terminology, pathologic differential diagnoses, pathogenesis, and prognosis. The patients were 40 to 68 years old, and included 4 males and 1 female. All patients were Hepatitis B surface antigen positive with para-tumorous cirrhosis. The largest dimensions of the neoplasms ranged from 6.0 to 14.0 cm. Satellite nodules, portal vein tumor thrombi, direct invasion into local tissues (right diaphragm, right adrenal gland, and gastric wall) as well as metastatic foci in lungs and abdominal lymph nodes were identified. Pathologically, the neoplasms consisted of carcinomatous and sarcomatous components. The carcinomatous components were exclusively conventional hepatocellular carcinomas in all 5 cases, whereas the sarcomatous components exhibited complex features. Confirmed by IHC studies, the sarcomatous elements in different cases included rhabdomyosarcomas, malignant fibrous histiocytomas, fibrosarcoma, and poorly differentiated spindle cells without distinctive differentiation. Furthermore, the sarcomatous elements in these 5 neoplasms stained negative for all the epithelial markers we applied for IHC staining, which support the pathologic diagnosis of carcinosarcoma rather than sarcomatoid carcinoma. The presence of transitional zones between carcinomatous and sarcomatous components may support the transformation theory. Four patients with palliative hepatectomy died within 6 months, whereas 1 patient is still alive 21 months after radical resection. The poor prognosis of hepatic carcinosarcoma may be due to their highly invasive and metastatic features. Radical resection of early stage hepatic carcinosarcoma may contribute to a relatively optimistic prognosis.

Clonality and heterogeneity of pulmonary blastoma from the viewpoint of genetic alterations: A case report

Biphasic pulmonary blastoma is a rare lung tumor with epithelial and mesenchymal components. Genetic alterations in this tumor are largely unknown, except for the presence of beta-catenin and p53 mutations and the absence of KRAS mutation. To understand the molecular process of histogenesis of this tumor, a whole genome allelic imbalance (AI) scanning using a high-resolution single nucleotide polymorphism array as well as mutational analysis of the p53, EGFR, KRAS and beta-catenin genes were performed against the epithelial and mesenchymal components in the primary tumor and a metastatic tumor in a case of pulmonary blastoma. AI at chromosome regions 14q24-q32 and 17p11-p13 and beta-catenin mutation were commonly detected in all tumors. On the other hand, AI at chromosome regions 3p11-p14 and 9p21-p24 and p53 mutation were detected only in the mesenchymal component in the primary tumor but not in the epithelial component in the primary tumor and the brain metastasis. Likewise, AI at chromosome regions 6p24-p25 and 6q14-q27 was detected in the epithelial component in the primary tumor and the brain metastasis but not in the mesenchymal component in the primary tumor. Furthermore, the genetic alterations detected in the metastatic tumor were completely the same as those in the epithelial component in the primary tumor, indicating that a tumor cell(s) in the epithelial component in the primary tumor selectively metastasized to the brain. These results indicate that this biphasic tumor is of monoclonal origin and the phenotypic heterogeneity of the tumor is due to the differences in the accumulated genetic alterations in each component of the tumor.