Pulmonary adenocarcinoma: review of 106 cases and proposed new classification

A clinicopathologic analysis of microscopic extension in small cell lung cancer and lung adenocarcinoma: Determination of clinical target volume with precise radiotherapy

PURPOSE

The identification of the clinical target volume (CTV) is particularly important in the precise radiotherapy of lung cancer. The purpose of this study was to determine the extension margin from gross tumor volume (GTV) to CTV in primary small cell lung cancer (SCLC) and lung adenocarcinoma (ADC) by microscopic extension (ME).

MATERIAL AND METHODS

The data of 25 cases of SCLC and 29 cases of ADC from August 2015 to August 2020 were analyzed. The measurement of tumor size between preoperative thoracic computed tomography (CT) and postoperative macroscopic specimens was compared, and the ME range of tumor cells was measured under a microscope to determine its correlation with clinical features and pathological manifestations.

RESULTS

A total of 217 slides were examined, corresponding to 103 slides for SCLC and 114 slides for ADC. The radiologic sizes of the tumors in SCLC and ADC were 12.8 and 7.9 mm, respectively (p = 0.09), and the macroscopic sizes were 12.5 and 8.5 mm, respectively (p = 0.07). There was a significant correlation between the radiologic and macroscopic size of the same tumor sample (r = 0.886). Compared with ADC, more SCLC tumor cells infiltrated through vascular or lymphatic dissemination (16% vs. 9%, p = 0.047). The mean ME value was 2.81 mm for SCLC and 2.02 mm for ADC (p = 0.012). To take into account 95% of the ME, a margin of 8 and 7.7 mm must be expanded for SCLC and ADC, respectively. The ME value of the tumor was related to the presence of atelectasis, the location of the tumor, and the Ki-67 cell proliferation index.

CONCLUSION

The GTV of the tumor was contoured according to CT images, which was basically consistent with the actual tumor size. The GTVs of SCLC and ADC should be expanded by 8 and 7.7 mm, respectively, to fully cover the subclinical lesions in 95% of cases.

The impact of immunohistochemistry on the classification of lung tumors

INTRODUCTION

To highlight the role of immunohistochemistry to lung cancer classification on the basis of existing guidelines and future perspectives.

AREAS COVERED

Four orienting key-issues were structured according to an extensive review on the English literature: a) cancer subtyping; b) best biomarkers and rules to follow; c) negative and positive profiling; d) suggestions towards an evidence-based proposal for lung cancer subtyping. A sparing material approach based on a limited number of specific markers is highly desirable. It includes p40 for squamous cell carcinoma ('no p40, no squamous'), TTF1 for adenocarcinoma, synaptophysin for neuroendocrine tumors and vimentin for sarcomatoid carcinoma. A close relationship between genotype and phenotype also supports a diagnostic role for negative profiles. Expert commentary: Highly specific and sensitive IHC markers according to positive and negative diagnostic algorithms seem appropriate for individual patients' lung cancer subtyping.

Ciliated adenocarcinomas of the lung: a tumor of non-terminal respiratory unit origin

Whereas most carcinomas occur through a sequential step, atypical adenomatous hyperplasia and bronchioloalveolar carcinoma pathway is known for pulmonary adenocarcinoma. This type is known as terminal respiratory unit adenocarcinoma. Based on our observation of transitions from normal ciliated columnar cells to adenocarcinoma via dysplastic mucous columnar cells, we reviewed our archive of pulmonary adenocarcinoma. Terminal respiratory unit type adenocarcinoma was defined as adenocarcinoma with type II pneumocyte, Clara cell, or bronchiolar cell morphology according to previous reports. Among 157 cases, 121 cases have been identified as terminal respiratory unit type adenocarcinoma and 36 cases as non-terminal respiratory unit type adenocarcinoma. Among non-terminal respiratory unit type adenocarcinoma, 24 cases revealed mucous columnar cell changes that were continuous with bronchial ciliated columnar cells. The mucous columnar cells became dysplastic showing loss of cilia, disorientation, and enlarged nuclei. Adenocarcinoma arose from these dysplastic mucous columnar cells and, characteristically, this type of adenocarcinoma showed acute inflammation, and honeycombing changes in the background. TTF1 immunostaining was consistently negative. In a case study with 14 males and 10 females, including 12 smokers or ex-smokers, EGFR and KRAS mutations were detected in 3 and 6 patients, respectively. We think that this kind of adenocarcinoma arising through mucous columnar cell change belongs to non-terminal respiratory unit type adenocarcinoma, and mucous columnar cell change is a precursor lesion of pulmonary adenocarcinoma.

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.

Pleomorphic carcinoma of the lung: A surgical outcome

OBJECTIVES

Pleomorphic carcinoma of the lung, a rare malignant disease with a dual-cell component of spindle and/or giant cells, and of epithelial cells, was defined in the World Health Organization classification updated in 1999. Reported prognoses are heterogeneous, and optimal treatment remains undefined.

METHODS

Data were retrospectively examined for 45 consecutive patients (41 men and 4 women) who had undergone surgical resection for pulmonary pleomorphic carcinoma.

RESULTS

Sarcomatous elements were as follows: 23 spindle cell types (51.1%), 11 giant cell types (24.4%), and 11 combined spindle and giant cell types (24.4%). Epithelial components were adenocarcinoma in 25 (55.6%) patients, squamous cell carcinoma in 8 (17.8%) patients, and large call carcinoma in 12 (26.7%) patients. Nodal status was classified as pN0 disease in 28 (62.2%) patients, pN1 disease in 5 (11.1%) patients, and pN2 disease in 12 (26.7%) patients. Even patients with pN0 disease frequently manifested vascular invasion (16/28 [57.1%]). Five-year overall survival and disease-free survival were 39.2% and 47.1%, respectively. Although the subtype of epithelial components, as well as sarcomatous elements, did not affect prognosis, overall survival (P = .02) and disease-free survival (P = .002) in patients with pN1/N2 disease were significantly worse than those in patients with pN0 disease. Most recurrences occurred at distant sites (14/20 [70.0%]), and recurrence within 6 months after resection was found in 10 patients (10/20 [50.0%]). Moreover, median survival time after confirmation of initial relapse was 2.6 months.

CONCLUSIONS

Pulmonary pleomorphic carcinoma, which often presented in symptomatic male smokers as a large peripheral lesion, carried a poor prognosis, even when early-stage disease was diagnosed and resected. Distant metastases occurred more frequently and earlier, and the survival after relapse was very short, suggesting that this entity should be considered to have a tremendously aggressive malignant behavior. Further investigation of biologic features of pulmonary pleomorphic carcinoma and therapeutic response is a high-priority issue, so that suitable treatment strategies can be planned.

Epidermal growth factor receptor mutations in lung cancers

In 2004, two groups reported somatic mutations in the gene for the epidermal growth factor receptor (EGFR) in patients with non-small cell lung cancer (NSCLC), which were highly correlated with the clinical response to the anticancer drug, gefitinib. Since then, a tremendous amount of knowledge has accumulated, and sheds light on significant oncological properties as well as the clinical relevance of this mutation, which could be applicable to other malignancies. The EGFR mutations are distributed throughout the kinase domain, but a deletion in exon 19 and the point mutation L858R in exon 21 account for approximately 90%, which confer a greater response to gefitinib treatment, compared with other types of EGFR mutations. These EGFR mutations in the tyrosine kinase domain are seldom acquired in cancers of the other organs and the mutations preferentially involve a subset of lung cancers, which are clinicopathologically characterized by female sex, non-smoking, adenocarcinoma histology and East Asian ethnicity. In Japan, the EGFR mutations are detected in approximately 30% of overall NSCLC and approximately 40% of surgically resected adenocarcinomas. The morphological features of adenocarcinomas harboring the mutations were reported to be frequent in those with bronchioloalveolar features, but it is suggested that the cellular lineage of the putative original cells of the cancers refines the subset more clearly. In the present study the current knowledge of EGFR mutations is reviewed, insights from which raise many further questions, and thus suggest new directions for future research.

EGFR Mutation Is Specific for Terminal Respiratory Unit Type Adenocarcinoma

We have previously reported that terminal-respiratory-unit (TRU) type adenocarcinoma is a distinct subset of lung adenocarcinoma in terms of molecular pathway for carcinogenesis and phenotypic profiles. This type of cancer shows TRU features, characterized by distinct cellular morphology and the expression of TTF-1 and surfactant proteins. Recently, two groups published novel mutations of the epidermal growth factor receptor (EGFR) that are closely associated with clinical response to gefitinib. The clinicopathologic features of gefitinib responders overlap with those of TRU-type adenocarcinoma, and the characteristics of TRU are likely to correspond to the bronchioloalveolar features reported as a predictor of gefitinib response. We therefore examined the characteristics of EGFR-mutated pulmonary adenocarcinomas with special reference to TRU-type adenocarcinoma. EGFR mutation was detected in 97 of 195 adenocarcinomas, 91 of 149 TRU-type adenocarcinomas and 6 of 46 tumors of other types. Conversely, 91 of 97 EGFR-mutated adenocarcinomas were categorized as TRU-type adenocarcinomas. This type-specific involvement was confirmed by logistic regression model. In addition, EGFR mutation was detected in some cases of atypical adenomatous hyperplasia, a preinvasive lesion of TRU-type adenocarcinoma. These findings further confirm that TRU-type-adenocarcinoma is a distinct adenocarcinoma subset in which a particular molecular pathway is involved.

Thyroid transcription factor 1 in pulmonary adenocarcinoma

AIMS

To discover whether variations in thyroid transcription factor 1 (TTF-1) staining in different subtypes and patterns of pulmonary adenocarcinoma are related to the putative origin of the tumour. In addition, to confirm the specificity of TTF-1 for pulmonary (as opposed to other sites) adenocarcinoma, to examine the possible prognostic relevance of TTF-1 positivity in lung cancer, and to review this laboratory's experience of TTF-1 in diagnostic practice.

MATERIALS/METHODS

In total, 128 primary lung adenocarcinomas, 106 primary non-pulmonary adenocarcinomas, and 37 pulmonary non-adenocarcinoma tumours were studied. In addition, 100 cases where TTF-1 was used in routine surgical pathology practice were investigated. Immunoperoxidase staining was performed on formalin fixed, paraffin wax embedded sections using anti-TTF-1 antibody. Staining was evaluated semiquantitatively using the frequency and intensity of nuclear positivity.

RESULTS

None of the 106 non-pulmonary adenocarcinomas expressed TTF-1 and only three of the 37 non-adenocarcinoma lung cancers, all neuroendocrine carcinomas, were positive. Of the pulmonary adenocarcinomas, 75% were strongly positive for TTF-1. Mucinous (two of six) and poorly differentiated adenocarcinomas (four of 10) were less likely to stain. Of the peripheral adenocarcinomas, 33 of 37 were positive, whereas only seven of 14 of those of bronchial origin stained strongly. Atypical adenomatous hyperplasia strongly expressed TTF-1. No "false positives" were encountered in the 100 routine diagnostic cases.

CONCLUSION

Positive TTF-1 staining is useful in the differential diagnosis of pulmonary adenocarcinomas. TTF-1 may be a lineage marker for tumours arising from the peripheral airway or alveolar epithelium and has no prognostic relevance.

Mouse model for lung tumorigenesis through Cre/lox controlled sporadic activation of the K-Ras oncogene

The onset of human lung cancer occurs through sequential mutations in oncogenes and tumor suppressor genes. Mutations in K-Ras play a prominent role in human non-small cell lung cancer. We have developed a mouse lung tumor model in which K-Ras can be sporadically activated through Cre-lox mediated somatic recombination. Adenoviral mediated delivery of Cre recombinase in lung epithelial cells gave rise to rapid onset of tumorigenesis, yielding pulmonary adenocarcinomas with 100% incidence after a short latency. The lung tumor lesions shared many features with human non-small cell lung cancer. Our data show that sporadic expression of the K-Ras oncogene is sufficient to elicit lung tumorigenesis. Therefore this model has many advantages over conventional transgenic models used thus far.

Pulmonary pleomorphic (spindle) cell carcinoma: peculiar clinicopathologic manifestations different from ordinary non-small cell carcinoma

Pleomorphic (spindle) cell carcinoma, also known as monophasic sarcomatoid carcinoma, is a rare primary pulmonary malignancy. This type of tumor shows concurrent presence of malignant epithelial and homologous sarcomatoid spindle cell components by co-expressing cytokeratin and vimentin in various degrees. Sixteen cases (four central endobronchial lesions and 12 peripheral parenchymal masses) were studied clinicopathologically. Men were affected far more frequently than women (13:3). The patients were between 56 and 80 years of age. The disease is strongly associated with smoking. Among seven of the patients who underwent surgical resection, four of them had mediastinum, pleura and chest wall invasions, and three of them had regional lymph node metastases. All of the patients succumbed to early distant metastases (range 2 weeks-5 months) in organs including brain, bone, adrenal gland, and unusual sites such as esophagus, jejunum, rectum and kidney. The remaining nine inoperable cases were late stage disease and treated with chemoradiotherapy with little effect. The median duration of survival was 3 months. All parenchymal masses appeared as cavities with marked central necrosis, and only peripheral rim of tumor cells was left. More definite diagnostic results will depend on further tissue sections and can be confirmed by immunohistochemical studies. Significantly fewer Ki-67, p53 and c-erb B-2 oncoprotein expressions were also noted.

Expression of CD44v6 but not E-cadherin or beta-catenin influences prognosis in primary pulmonary adenocarcinoma

Primary pulmonary adenocarcinoma was studied, looking for relationships between the expression of cell adhesion molecules (CAMs) E-cadherin, beta-catenin and CD44v6, and clinicopathological tumour parameters and patient post-operative survival. Formalin-fixed, paraffin-embedded tissue from 120 primary lung adenocarcinomas, including 23 poorly differentiated tumours, 17 of probable bronchial origin, and 29 with a prominent bronchioloalveolar pattern, together with nodal metastatic tumour from 34 of these patients was stained using monoclonal antibodies and immunohistochemistry. Sections were scored either high level (>10% cells positive) or low level (<10% positive). High level expression of CD44v6 was retained in 28.4% (34/120) of tumours, while high levels of E-cadherin (57.5%, 69/120) and beta-catenin (80. 8%, 97/120) were more frequent. For all CAMs, staining levels did not correlate with nodal status, stage or tumour type. The apical or basal staining seen in normal bronchial and alveolar epithelium was often seen in papillary, glandular, and bronchioloalveolar areas of tumour, while solid invasive tumour more often showed pericellular staining. When the staining for each CAM in 34 nodal metastases was compared with that in the corresponding primary tumour, a high degree of concordance was found, with no tendency for metastases to show less staining than the primary tumour. Expression of E-cadherin and beta-catenin in the primary tumour had no influence on post-operative survival, but patients whose tumours had low level CD44v6 expression had a poorer post-operative survival than those with high levels of CD44v6 (p=0.0014 for all patients, p=0.0012 for stage I patients only). In primary pulmonary adenocarcinoma, the levels of expression of E-cadherin, beta-catenin, and CD44v6 are not associated with lymph node metastases or tumour stage but the staining pattern is associated with tumour morphology. Low levels of CD44v6 expression predict a poor post-operative survival, independently of stage, while there is no such relationship with the expression of E-cadherin or beta-catenin.

Clear cell adenocarcinoma with endobronchial polypoid growth

Clear cell adenocarcinoma of the lung is extremely rare. On radiography, a 45-year-old female with fever was found to have an abnormal shadow in the left lower lung field. Bronchoscopy revealed a polypoid tumor in the left bronchus. On biopsy, the tumor was determined to be adenocarcinoma. Preoperative examination found no tumors outside of the lung. The patient underwent left lower lobectomy with bronchial wedge resection. The tumor had completely obstructed and dilated the left lower bronchus, but had not invaded the tissue outside the bronchial wall. Microscopically, the cytoplasm of the tumor cells contained abundant glycogen, and the tumor had solid and glandular structures. The tumor was diagnosed as clear cell adenocarcinoma of the lung.

Evaluation of microscopic tumor extension in non-small-cell lung cancer for three-dimensional conformal radiotherapy planning

PURPOSE

One of the most difficult steps of the three-dimensional conformal radiotherapy (3DCRT) is to define the clinical target volume (CTV) according to the degree of local microscopic extension (ME). In this study, we tried to quantify this ME in non-small-cell lung cancer (NSCLC).

MATERIAL AND METHODS

Seventy NSCLC surgical resection specimens for which the border between tumor and adjacent lung parenchyma were examined on routine sections. This border was identified with the naked eye, outlined with a marker pen, and the value of the local ME outside of this border was measured with an eyepiece micrometer. The pattern of histologic spread was also determined.

RESULTS

A total of 354 slides were examined, corresponding to 176 slides for adenocarcinoma (ADC) and 178 slides for squamous cell carcinoma (SCC). The mean value of ME was 2.69 mm for ADC and 1.48 mm for SCC (p = 0.01). The usual 5-mm margin covers 80% of the ME for ADC and 91% for SCC. To take into account 95% of the ME, a margin of 8 mm and 6 mm must be chosen for ADC and SCC, respectively. Aerogenous dissemination was the most frequent pattern observed for all groups, followed by lymphatic invasion for ADC and interstitial extension for SCC.

CONCLUSION

The ME was different between ADC and SCC. The usual CTV margin of 5 mm appears inadequate to cover the ME for either group, and it must be increased to 8 mm and 6 mm for ADC and SCC, respectively, to cover 95% of the ME. This approach is obviously integrated into the overall 3DCRT procedure and with other margins.

Pathological-radiological correlations: pathological and radiological correlation of endobronchial neoplasms: part II, malignant tumors

The majority of lung neoplasms are malignant. Many of these are central and have an associated endobronchial component. Most such neoplasms are of surface epithelial origin; however, neoplasms of submucosal gland, mesenchymal, and lymphoreticular origin may also demonstrate an endobronchial component. Because of their endobronchial location and associated symptoms, these patients often present at an earlier stage than purely parenchymal lung malignancies. The radiographic features in such cases may be similar to those associated with benign endobronchial tumors; however, there are certain radiological signs that are more suggestive of a malignant process. Despite these circumstances, conservative management such as endoscopic excision are inappropriate in most instances. The clinicopathologic and radiological features of these lesions are detailed.

The pattern of K-ras mutation in pulmonary adenocarcinoma defines a new pathway of tumour development in the human lung

Codon 12 of the K-ras oncogene was screened for mutations in 65 surgically-resected primary pulmonary adenocarcinomas and in 32 tissue foci of alveolar atypical hyperplasia (AAH) by a polymerase chain reaction (PCR)-based method. Mutations in either position 1 or position 2 of codon 12 were detected in 16 tumours (25 per cent). When analysed by site of origin, mutations were seen in 9/26 (35 per cent) parenchymal and in 0/12 bronchial adenocarcinomas (P < 0-02), K-ras mutations were seen in five AAH lesions from four patients. DNA sequencing showed that the great majority of mutations in both adenocarcinomas and AAH were G-T transversions. These findings provide support for the classification of pulmonary adenocarcinomas into bronchial and parenchymal subtypes and also provide molecular evidence to support the importance of AAH in the development of parenchymal cancers.

Loss of heterozygosity at 5q21 in non-small cell lung cancer: a frequent event but without evidence of apc mutation

Four genetic polymorphisms in the APC and MCC genes at chromosome 5q21 were analysed for loss of heterozygosity (LOH) in 97 primary squamous carcinomas and adenocarcinomas of the lung. LOH was identified in at least two polymorphic loci in 41 percent of informative cases. There was no significant difference in the frequency of LOH between squamous carcinomas and adenocarcinomas. Within the adenocarcinoma group, however, LOH appeared to be more common in tumours having a bronchial origin (5/9; 56 per cent) than in parenchymal adenocarcinoma (6/21; 29 per cent). All 32 tumours showing LOH at one or more polymorphic sites were examined for mutations in the mutation cluster region (MCR) of APC by single-strand conformational polymorphism (SSCP) analysis. Mutations were not detected in any of these cases. We therefore propose that it is likely that a tumour suppressor gene on 5q other than APC is involved in the pathogenesis of lung cancer.

Atypical alveolar hyperplasia: relationship with pulmonary adenocarcinoma, p53, and c-erbB-2 expression

Atypical alveolar hyperplasia (AAH) has recently been described in human lungs in association with primary lung cancer, particularly adenocarcinoma. Unlike proximal bronchogenic carcinoma, peripheral (parenchymal) adenocarcinoma of the lung does not have a well-recognized progenitor lesion. Epidemiological morphometric, and cytofluorometric data in the literature suggest that AAH is a candidate premalignant entity. In this study, 97 AAH lesions were found in lungs resected from 29 patients (1-13 lesions per case, mean 3.5) being treated for presumed carcinoma (25/29 had adenocarcinoma). From a study case-load of 285 adenocarcinoma-bearing lungs, the AAH incidence was 8.8 per cent. Sections of 67 AAH lesions from 19 patients were stained using monoclonal antibodies against Ki67 (MIB1), p53 (DO7), and c-erbB-2 (NCL-CB11). Ki67 was expressed in up to 10 per cent of AAH nuclei. Thirty-nine lesions (58 per cent) showed stainable p53 protein, while five (7 per cent) expressed membrane c-erbB-2 oncoprotein. These latter five lesions were all strongly positive for p53, and both p53 and c-erbB staining was associated with increased cellular crowding and pleomorphism in AAH. These data demonstrate that AAH exhibits some genetic changes associated with malignancy and thereby support the hypothesis that AAH is premalignant.

Pleomorphic (spindle/giant cell) carcinoma of the lung. A clinicopathologic correlation of 78 cases

BACKGROUND

The authors undertook this study to define the clinical and histologic characteristics of spindle and giant cell carcinomas of the lung and the survival and prognostic features of these tumors.

METHODS

Seventy-eight cases of pleomorphic (spindle and/or giant cell) carcinoma of the lung were studied by light microscopy and immunohistochemistry to establish clinical, gross, and histologic parameters. Follow-up information was obtained from contributing physicians and analyzed by statistical means to determine prognostically significant parameters.

RESULTS

The patient population consisted of 57 men and 21 women (male to female ratio, 2.7 to 1) between the ages of 35 and 83 years (mean, 62 years). Clinically, 58 patients (80%) presented with symptoms including thoracic pain, cough, and hemoptysis, whereas 14 (18%) were asymptomatic. At the time of diagnosis, 41% of the patients had clinical Stage I lesions, 6% Stage II lesions, 39% Stage III lesions, and 12% Stage IV lesions. Histologically, foci of squamous cell carcinoma were present in 8% of the tumors, large cell carcinoma in 25%, and adenocarcinoma in 45%. The remaining 22% of neoplasms were completely spindle and/or giant cell carcinomas. Spindle and giant cell carcinomas were found together in 38% of the patients. In the 69 patients for whom follow-up information was obtained, 53 (77%) died within 7 days to 6 years after diagnosis, with a 23-month mean survival (median, 10 months) (Kaplan-Meier method). There was a significant shortening of survival for patients with tumor size greater than 5 cm, clinical stage greater than 1, and lymph node involvement. The presence of nodal metastases was the most significant single prognostic factor, whereas the presence of squamous or adenocarcinomatous differentiation did not have an impact on length of survival.

CONCLUSIONS

The frequency with which spindle and giant cell carcinomas are found together, their frequent association with other histologic subtypes of lung carcinoma, and the similar clinicopathologic features of these tumors suggest that they are best regarded as one type of lung cancer called pleomorphic carcinoma.

Mesothelioma-like tumors of the pleura: a review of 72 autopsy cases

The 72 mesothelioma-like tumors of the pleura (MLTP) found among 33 500 autopsy cases collected over more than 30 years are reviewed. MLTP have a worse prognosis than the 106 cases of pleural mesothelioma autopsied in our institutes with regard to survival time and metastatic spread. In MLTP, adenocarcinomas predominate with a wide range of histological and cytological variation and prominent development of connective tissue having its origin in the periphery of the lung. These intrapulmonary primary tumors often fulfill the criteria of pulmonary scar cancer. Etiologically, there is no correlation between the origin of this tumor and smoking or exposure to asbestos. The absence of mucus formation and glandular differentiation, together with the presence of spindle-shaped carcinoma components and strong mesothelial or stroma proliferation, can make the differential diagnosis between this tumor type and mesothelioma difficult. Immunohistological investigations were performed on 11 cases with antibodies against intermediate filament proteins, vascular endothelium, collagen IV, macrophage antigens, carcinoembryonic antigen (CEA), LeuM1, and the antibody BerEP4. Our investigation shows that a battery of several tumor markers, such as antibodies against LeuM1, CEA, and the antibody BerEP4, as well as staining with periodic acid/Schiff/diastase discriminate primary from secondary pleural neoplasms, whilst intermediate filament proteins alone are of little diagnostic value.

Special subtypes of pulmonary adenocarcinomas indicated by different tumor cell HLA-expression and stromal infiltrates. A light, electron microscopic and immunohistologic study

A total of 31 human peripheral adenocarcinomas (AC) of the lung were subclassified by light and electron microscopy according to their phenotypic characteristics. The expression of HLA-A,B,C and HLA-DR on tumor cells, and the degree of subclassified mononuclear cell infiltration were determined using immunohistologic and morphometric methods. The study shows that pulmonary AC can be subdivided in two main types with different properties. The first type is characterized by mucin production comparable to that of bronchial goblet cells. These mucinous AC of type I show nearly no expression of HLA-DR; the tumor volume fraction with HLA-A,B,C expression is greatest in highly differentiated AC I, and decreases significantly with lower grades of differentiation. The AC of type II, possibly originating from the bronchioloalveolar transitional zone, show properties of Clara cells and of type II-pneumocytes by light and electron microscopy. These features include apically located electron-dense granules and lamellar bodies occurring often simultaneously. Both groups of HLA-antigens, HLA-A,B,C and HLA-DR, are homogeneously distributed in a similar phenotypic fashion to Clara cells and pneumocytes II of the normal lung. The significant differences in mononuclear cell infiltration between the two tumor types are possibly induced by the different HLA-DR expression, which have not been seen in AC from other sites. In AC II with homogeneous HLA-DR expression in the tumor epithelium, the numbers of tumor-infiltrating Langerhans cells, and T- and B-lymphocytes are significantly higher than in AC I, possibly indicating better host immunologic defense mechanisms against these tumors.

Alveolar atypical hyperplasia in association with primary pulmonary adenocarcinoma: a clinicopathological study of 10 cases

BACKGROUND

A distinctive cytologically atypical lesion has been found in patients with primary adenocarcinoma of the lung. The aim of this study was to characterise the lesion and assess its role in tumour pathogenesis.

METHODS

Lung parenchyma from 175 consecutive resection specimens for primary pulmonary adenocarcinoma were examined. Foci of atypical hyperplasia were identified. Cell proliferation state and expression of S100 and carcinoembryonic antigens were evaluated by immunohistochemistry. Clinical data on cigarette smoking and occupational exposure to carcinogens were abstracted from inpatient case notes.

RESULTS

Ten cases (5.7%) with these distinctive cytologically atypical lesions were identified. The lesions showed immunohistochemical evidence of increased cell proliferation and focal carcinoembryonic antigen expression. The associated adenocarcinomas were of peripheral (parenchymal) type. There was an association with cigarette smoking and two of the 10 patients had synchronous carcinomas elsewhere in the lung.

CONCLUSION

The clinical and pathological associations of these lesions suggest that they may be important in the histogenesis of primary pulmonary adenocarcinoma.

The ultrastructure of oesophageal carcinomas: multidirectional differentiation. A transmission electron microscopic study of 43 cases

Forty-three oesophageal carcinomas, comprising 15 squamous cell carcinomas, 22 adenocarcinomas, 5 small cell carcinomas, and 1 adenosquamous carcinoma, were examined by transmission electron microscopy. The ultrastructural features of each tumour type are detailed. Multi-directional differentiation (heterogeneity) was observed in 11 cases: 5 squamous cell carcinomas with focal glandular features; 4 adenocarcinomas with focal squamous features; and 2 small cell carcinomas, one with glandular and the other with squamous features. Abnormal distributions of desmosomes in squamous cell carcinomas and of polarity of tumour cells in adenocarcinomas are described.

Expression of neuroendocrine markers (neuronspecific enolase, synaptophysin and bombesin) in carcinoma of the lung

The value of immunoreactivity of antibodies against neuronspecific enolase (NSE), bombesin (GRP), and synaptophysin (SY 38) as markers for various human lung carcinoma has been assessed. One hundred-forty-two primary bronchus carcinomas (small cell anaplastic carcinoma, epidermoid carcinoma, adeno carcinoma, and large cell anaplastic carcinoma) were studied by the indirect immunoperoxidase method (PAP). SY 38 was found to react positively in 49/68 (79%) of the small cell anaplastic carcinoma (SCCL) and in 6/74 (8%) of the non-small cell carcinoma of the lung (NSCCL). Positive immunohistochemical data with antibody SY 38 showed in some cases an immunoreactive polypeptide of Mr = 40.000 obtained by immunoblotting similar in molecular weight as described for synaptophysin in other tumours. Reactivity of NSE was observed in 41/68 (61%) of the SCCL and in 8/74 (10%) of the NSCCL. Positive reactivity to GRP was similar to NSE in 42/68 (62%) of SCCL and in 7/74 (10%) of NSCCL. All cases of NSCCL reacting positively to SY 38 were found to react positively to NSE, and to GRP. Prognostic value of SY 38 was calculated vp = 0.71 for positive prediction and vn = 0.91 for negative prediction. The data indicate that SY 38 represents the broadest marker for neuroendocrine carcinoma of the lung since in addition to the majority of SCCL about 10% of NSCCL are recognized by the antibody SY 38.