Bronchiolar carcinoma: report of 11 cases and review of the literature

Cribriform growth pattern in lung adenocarcinoma: More aggressive and poorer prognosis than acinar growth pattern

The predictive value of prognosis based on the histopathological subtype is a critical criterion in the new classification of lung adenocarcinoma published in 2011 by the International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) (IASLC/ATS/ERS). In this new classification, the differences of histopathology and prognosis are two considerable parameters to classify the subtypes of lung adenocarcinoma. Cribriform growth pattern is regarded as a variant of acinar growth pattern in lung adenocarcinoma, however, more and more studies pointed out that cribriform growth pattern is associated with more aggressive histopathological structures, higher proportion of recurrence rates, and shorter postoperative survival than acinar growth pattern. These features are similar to solid or micropapillary predominant adenocarcinoma. In this review, we summarized the clinicopathological features, prognosis, and genetic variations of cribriform growth pattern of lung adenocarcinoma, and provided a novel insight into the diagnosis and treatment of cribriform lung adenocarcinoma.

The solitary pulmonary nodule: a primer on differential diagnosis

Despite significant advances in noninvasive imaging techniques, management of the solitary pulmonary nodule (SPN) remains a challenge for chest physicians. Patients with SPNs are frequently asymptomatic, and the physical examination is seldom revealing. Accurate diagnosis is essential, because >50% of patients will require prompt disease-specific therapy. The complexity of the problem is best appreciated by reviewing the differential list, which includes nearly 80 distinct clinical entities. Consequently, a thorough understanding of the more common etiologies is necessary to adequately treat patients with SPNs.

Diffuse bronchiolo-alveolar carcinoma in a dog

An eight-year-old female German wirehaired pointer was presented with signs of respiratory distress. Clinical examination, laboratory results, thoracic radiography and echocardiography indicated the presence of a diffuse interstitial lung disease with secondary appropriate erythrocytosis, pulmonary hypertension and cor pulmonale. Transthoracic fine needle aspiration biopsy of the lung suggested malignant epithelial neoplasia. A primary lung cancer with an unusually diffuse distribution of miliary/micronodular lesions was found at postmortem examination. Histological diagnosis was bronchiolo-alveolar carcinoma. Bronchiolo-alveolar carcinoma can occasionally occur in a diffuse fashion involving most or all of the lung parenchyma. In man, diffuse bronchiolo-alveolar carcinoma is considered a great imitator of other, more common diffuse interstitial forms of lung disease. This case report indicates that it is also a differential diagnosis to consider in dogs.

Retrovirus-induced ovine pulmonary adenocarcinoma, an animal model for lung cancer

Studies on the molecular mechanisms of transformation of retrovirus-induced neoplasms in domestic and laboratory animal species have provided insights into the genetic basis of cancer. Ovine pulmonary adenocarcinoma (OPA) is a retrovirus-induced spontaneous lung tumor of sheep that has striking analogies to some forms of human adenocarcinoma. The etiologic agent of OPA, jaagsiekte sheep retrovirus (JSRV), is unique among retroviruses for having a specific tropism for the differentiated epithelial cells of the lung, and it is the only virus known to cause a naturally occurring lung adenocarcinoma. Expression of the JSRV envelope protein is sufficient to induce cell transformation in vitro, possibly via the activation of the phosphatidylinositol 3-kinase/Akt-signaling pathway mediated by the cytoplasmic tail of the transmembrane protein. The aim of this review is to draw the attention of basic and clinical scientists engaged in lung cancer research to this unique animal model, to explore the possible use of OPA as a tool to investigate the mechanisms of pulmonary carcinogenesis, and to underline the similarities between OPA and some forms of human lung adenocarcinoma. The possibility of a viral etiology for the latter will be evaluated in this review.

Development of pulmonary bronchiolo-alveolar adenocarcinomas in transgenic mice overexpressing murine c-myc and epidermal growth factor in alveolar type II pneumocytes

Transgenic mouse models were established to study tumorigenesis of bronchiolo-alveolar adenocarcinomas derived from alveolar type II pneumocytes (AT-II cells). Transgenic lines expressing the murine oncogene c- myc under the control of the lung-specific surfactant protein C promoter developed multifocal bronchiolo-alveolar hyperplasias, adenomas and carcinomas respectively, whereas transgenic lines expressing a secretable form of the epidermal growth factor (IgEGF), a structural and functional homologue of transforming growth factor alpha (TGF alpha), developed hyperplasias of the alveolar epithelium. Since the oncogenes c- myc and TGF alpha are frequently overexpressed in human lung bronchiolo-alveolar adenocarcinomas, these mouse lines are useful as models for human lung bronchiolo-alveolar adenocarcinomas. The average life expectancies of hemizygous and homozygous c- myc transgenics were 14.25 months and 9.2 months, respectively, suggesting that a dosage effect of c- myc caused an accelerated bronchiolo-alveolar adenocarcinoma formation. First analyses of double transgenics, hemizygous for both c- myc and IgEGF, show that these mice develop bronchiolo-alveolar adenocarcinomas at the average age of 9 months, indicating that these oncogenes cooperate during the lung cancer formation. Our results demonstrate that c- myc and EGF are directly involved and cooperate with one another during formation of bronchiolo-alveolar adenocarcinomas in the lung.

Clinical features of patients with stage IIIB and IV bronchioloalveolar carcinoma of the lung

BACKGROUND

The incidence of bronchioloalveolar carcinoma of the lung (BAC), a pathologically distinct type of nonsmall cell lung carcinoma (NSCLC), appears to be rising. In this study, the authors compared data on the clinical presentation and clinical courses of patients with Stage IIIB and IV BAC with data on other types of NSCLC.

METHODS

The authors collected clinical, radiographic, and pathology information about 28 patients with Stage IIIB and IV BAC and 124 patients with other histologic types of NSCLC.

RESULTS

Twelve of 28 BAC patients (43%) were women, compared with 40 of 124 control patients (32%). Nine (32%) of the patients with BAC had never smoked cigarettes, versus 20 controls (16%) (P = 0.02). Eighteen patients (64%) with BAC had bilateral multilobar or multicentric pulmonary involvement, compared with 13 controls (15%) (P < 0.001). Patients with advanced stage (IIIB and IV) BAC had a median survival of 15 months from the time of diagnosis; for patients with other types of Stage IIIB and IV NSCLC, had a median survival of 10 months (P = 0.01).

CONCLUSIONS

Patients with BAC of the lung have clinical, radiographic, and pathologic characteristics that distinguish them from patients with other types of NSCLC. A greater proportion of women and nonsmokers present with BAC than with other types of NSCLC. Patients with advanced stage BAC are more likely to have bilateral diffuse pulmonary involvement, are less likely to develop brain metastases, and have longer survival than patients with other types of Stage IIIB and IV NSCLC. Further research is warranted to define etiology, molecular abnormalities, and more effective therapeutic interventions.

Distinction of consolidative bronchioloalveolar carcinoma from pneumonia: do CT criteria work?

OBJECTIVE

The purpose of this study was to compare the CT findings of consolidative bronchioloalveolar carcinoma (BAC) with consolidative infectious pneumonia and determine if any pattern revealed by CT is more specific for one disease than the other and may therefore expedite a diagnosis of consolidative BAC using CT.

MATERIALS AND METHODS

The CT findings in 20 patients with consolidative BAC and 20 patients with consolidative infectious pneumonia were reviewed. Radiologic features included the presence and distribution of consolidation, nodules, and ground-glass opacities; the presence of air bronchogram, mucous bronchogram, contrast enhancement, cysts, or cavities within the consolidation; and pulmonary fibrosis or significant parenchyma scarring.

RESULTS

Statistically significant (p < .003) findings that were more often seen on CT scans of patients with consolidative BAC than on those of patients with consolidative pneumonia included coexisting nodules (p < .001) and a peripheral distribution of consolidation (p < .001).

CONCLUSION

When nonresolving peripheral consolidative pneumonia, especially with associated nodules, is shown on CT, radiologists should suspect BAC when the patient is an adult with normal immunity.

FHIT and p53 gene abnormalities in bronchioloalveolar carcinomas. Correlations with clinicopathological data and K-ras mutations

Bronchioloalveolar carcinoma (BAC) is a particular type of adenocarcinoma of the lung which accounts for up to 9 per cent of pulmonary malignancies. The aetiology and pathogenesis of this unique neoplastic disease are still unclear. Three histological subtypes of BAC have been recognized: mucinous, non-mucinous, and sclerosing. Of these, mucinous and sclerosing BAC have a worse prognosis than non-mucinous tumours. The different morphological patterns and clinical outcomes of the subtypes of BAC suggest differences in their biological behaviour. Previous reports have shown that the mucinous form of BAC is characterized by constant mutations at codon 12 of the K-ras gene, whereas the other two histotypes show a frequency of K-ras mutations which is not different from that observed in conventional lung adenocarcinomas. The present study of a series of 51 BACs, previously investigated for K-ras gene mutations, has evaluated the status of two other genes, p53 and FHIT, known to be frequently altered in non-small cell lung cancer. Loss of heterozygosity at microsatellite-containing loci located within the FHIT gene was observed in 22 (43 per cent) BACs. The distribution of FHIT gene abnormalities was not statistically different in the three histological subtypes. p53 mutations were present in 13 (32 per cent) non-mucinous/sclerosing BACs, while no mutations were seen in mucinous tumours (P = 0.039). Correlations with clinicopathological parameters showed that p53 mutations in BACs are associated with more aggressive tumours. No correlations were observed between FHIT or K-ras gene abnormalities and clinicopathological data. In conclusion, these results indicate that FHIT alterations are frequently involved in BAC tumourigenesis and that genetic changes in the p53 and K-ras genes can distinguish between different histotypes of BAC.

Differentiating cytological features of bronchioloalveolar carcinoma from adenocarcinoma of the lung in fine-needle aspirations: a statistical analysis of 27 cases

Bronchioloalveolar carcinoma (BAC) is an uncommon type of lung carcinoma that is important to distinguish from adenocarcinoma (adenoCA) because of its different biological behavior. Although the features of BAC have often been described in cytological material other than fine-needle aspirations (FNA), they have rarely been detailed in FNA specimens. We undertook to delineate the differentiating cytological features of 13 cases of BAC (7 of the nonsecretory type and 6 of the secretory type) and of 14 cases of bronchogenic adenoCA in FNA material, looking at 17 cytological criteria and using statistical analysis. When statistically analyzed with chi-square and Pearson's correlation, only 3 of the 17 features were found to be good discriminants for distinguishing nonsecretory BAC (NS-BAC) from adenoCA: prominence of monolayered tumor sheets, fine chromatin pattern, and mild cellular pleomorphism correlated significantly with NS-BAC. On the other hand, only the prominence of nuclear grooves and the abundance of extracellular mucin correlated significantly with secretory BAC (S-BAC) when compared to adenoCA. When using a logistic regression analysis, NS-BAC and S-BAC were best discriminated from adenoCA by the prominence of monolayered tumor sheets and by the abundance of extracellular mucin, respectively. We conclude that, in most instances, it is possible to make an accurate diagnosis of BAC and to distinguish it from adenoCA of the lung in FNA material.

Bronchioloalveolar lung carcinomas: K-ras mutations are constant events in the mucinous subtype

Bronchioloalveolar carcinoma (BAC) is a form of peripheral lung adenocarcinoma growing as a single layer of malignant cells along the walls of terminal airways. The existence of BAC as a separate clinico-pathological entity has been a matter of controversy, mainly because its histogenesis is uncertain and it is not easily distinguishable from conventional lung adenocarcinoma (CLA). Three subtypes of BAC have been described using histological and cytological criteria: mucinous, non-mucinous, and sclerosing. The clinical behaviour of BAC appears to be dependent on the histological subtype. The different morphological patterns and clinical outcome of the subtypes of BAC suggest that their biological behaviour may be different from one another and from CLA. This study has investigated 58 BACs (10 mucinous, 40 non-mucinous, and 8 sclerosing) and 50 control CLAs for mutations at codon 12 of the K-ras oncogene. Twenty-one (36 per cent) BACs and 13 (26 per cent) CLAs showed K-ras mutations. A clear association (P < 0.0001) between K-ras mutations and the mucinous type of BAC was observed: all 10 mucinous tumours examined were scored positive for mutations in the K-ras gene, while only 9 (23 per cent) of the 40 non-mucinous and 2 (25 per cent) of the 8 sclerosing BACs were found to be positive. The frequency of ras mutations in non-mucinous BAC, sclerosing BAC, and CLA was not statistically different. Our data indicate that BACs are a heterogeneous group of lung tumours and that the mucinous form might represent a biological entity separate from both the other two BAC types and CLA.

Non-small cell lung cancer. Part I: Biology, diagnosis, and staging

Squamous, large cell, and adenocarcinoma, collectively termed non-small cell lung cancer (NSCLC), are diagnosed in approximately 75% of patients with lung cancer in the United States. The treatment of these three tumor cell types is approached in virtually identical fashion because, in contrast to small cell carcinoma of the lung, NSCLC more frequently presents with localized disease at the time of diagnosis and is thus more often amenable to surgical resection but less frequently responds to chemotherapy and irradiation. Cigarette smoking is etiologically related to the development of NSCLC in the great majority of cases. Genetic mutations in dominant oncogenes such as K-ras, loss of genetic material on chromosomes 3p, 11p, and 17p, and deletions or mutations in tumor suppressor genes such as rb and p53 have been documented in NSCLC tumors and tumor cell lines. NSCLC is diagnosed because of symptoms related to the primary tumor or regional or distant metastases, as an incidental finding on chest radiograph, or rarely because of a paraneoplastic syndrome such as hypercalcemia or hypertrophic pulmonary osteoarthropathy. Screening smokers with periodic chest radiographs and sputum cytologic examination has not been shown to reduce mortality. The diagnosis of NSCLC is usually established by fiberoptic bronchoscopy or percutaneous fine-needle aspiration, by biopsy of a regional or distant metastatic site, or at the time of thoracotomy. Pathologically, NSCLC arises in a setting of bronchial mucosal metaplasia and dysplasia that progressively increase over time. Squamous carcinoma more often presents as a central endobronchial lesion, while large cell and adenocarcinoma have a tendency to arise in the lung periphery and invade the pleura. Once the diagnosis is made, the extent of tumor dissemination is determined. Since most NSCLC patients who survive 5 years or longer have undergone surgical resection of their cancers, the focus of the staging process is to determine whether the patient is a candidate for thoracotomy with curative intent. The dominant prognostic factors in NSCLC are extent of tumor dissemination, ambulatory or performance status, and degree of weight loss. Stages I and II NSCLC, which are confined within the pleural reflection, are managed by surgical resection whenever possible, with approximate 5-year survival of 45% and 25%, respectively. Patients with stage IIIa cancers, in which the primary tumor has extended through the pleura or metastasized to ipsilateral or subcarinal lymph nodes, can occasionally be surgically resected but are often managed with definitive thoracic irradiation and have 5-year survival of approximately 15%.(ABSTRACT TRUNCATED AT 400 WORDS)

Pulmonary mucinous cystic tumors of borderline malignancy

Mucus-filled cystic tumors of low or borderline malignant potential, well recognized in ovary and appendix, have received little attention in the lung. We present data on 11 patients, all of whom had solitary pulmonary nodules resected in which mucus was the major histologic component. Prognosis appears good; no patient had developed local recurrence or metastatic spread of tumor (follow-up, 1 to 9.5 years; mean, 4.7 years). Columnar mucus-producing cells lined the cysts in all cases, with cytologic and architectural atypia varying from minimal to microscopic foci of carcinoma; paucicellular mucus dissection into surrounding lung analogous to pseudomyxoma peritonei was seen in seven cases. The histologic and clinical findings are consistent with a mucinous cystic tumor of low or borderline malignant potential.

Surfactant production by neoplastic type II pneumocytes

A bronchioloalveolar carcinoma of type II pneumocyte differentiation with abundant intraluminal secretion, histochemically and histologically mimicking alveolar proteinosis, is described. The tumor was of the diffuse type, involving almost the entire lower lobe of the left lung. The luminal aspect of the cells showed evidence of apocrine secretion. Ultrastructurally, the cells were characterized by the presence of cytoplasmic lamellar bodies. There were occasional cells with intranuclear tubules, and numerous rounded fragments of cytoplasm were present in the lumen as evidence of the apocrine activity. The intraalveolar secretion was composed of lamellar bodies in various stages of dissolution, tubular myelinlike networks characteristic of surfactant, and amorphous, granular material. This is the first reported instance of morphologic demonstration of surfactant secretion by a bronchioloalveolar carcinoma.

Glandular neoplasia of the lung. A proposed analogy to colonic tumors

In 62 consecutive resections for adenocarcinoma of the lung, 50 cases (81%) had single adenocarcinomas and 12 (19%) had multiple adenocarcinomas. In seven of these 12 patients, two adenocarcinomas were found. In the other five patients, the specimen contained a dominant adenocarcinoma and several 0.1- to 1-cm nodules of similar histologic appearance. In four of the 50 single tumor patients and one of seven double tumor patients, 1- to 2-mm nodules were found along with adenocarcinomas that we interpreted as being bronchioloalveolar tumors of uncertain malignant potential. An analogy is drawn between these four types of findings and single tumors of the colon, double tumors of the colon, polyposis syndromes, and tubular adenomas of the colon, respectively.

Placental-like alkaline phosphatase reactivity in human tumors: an immunohistochemical study of 520 cases

Placental-like alkaline phosphatase (PLAP) activity has been reported in various human neoplasms of both somatic and germ cell types. The expression of PLAP was examined with a polyclonal antibody and the immunoperoxidase technique in formalin-fixed, paraffin-embedded sections of 37 germ cell neoplasms and 483 somatic tumors. The expression of keratin and epithelial membrane antigen (EMA) was concurrently assessed to determine whether these stains were helpful in distinguishing germ cell neoplasms from somatic tumors that might mimic them microscopically. All germ cell lesions were reactive for PLAP, but so were 62 somatic carcinomas, usually in female müllerian, intestinal, and lung cancers and less often in carcinomas of the breast and kidney. PLAP-reactive somatic tumors exhibited EMA and keratin positivity in the absence of prior protease digestion, whereas germ cell neoplasms failed to do so. Malignant mesotheliomas were nonreactive for PLAP, as were carcinomas of the nasopharynx, adrenals, liver, pancreas, stomach, prostate, and urinary bladder. PLAP is a highly sensitive but nonspecific immunohistologic marker of germ cell differentiation. However, non-protease-enhanced stains for keratin and EMA allow separation of germ cell and somatic carcinomas, despite their shared capacity for PLAP expression. In somatic neoplasms, PLAP immunoreactivity might be of potential use in predicting possible primary sources for metastatic tumors of unknown origin.

Papillary adenocarcinoma of lung with psammoma bodies: report of a case derived from type II pneumocytes

A 52-year-old woman underwent thoracotomy for the removal of a mass in the middle lobe of the right lung. Light microscopy showed a tumour with the morphology of a papillary adenocarcinoma with numerous psammoma bodies. Electron microscopy revealed the tumour cells to possess the lamellated intracytoplasmic inclusions characteristic of normal and neoplastic type II pneumocytes. Psammoma bodies have not previously been reported in type II cell carcinoma of the lung. Alveolar cell carcinoma should be considered in the differential diagnosis of a papillary adenocarcinoma with psammoma bodies occurring in the lung.

Bronchioloalveolar carcinoma: The significance of two histopathologic types

A review of the pathologic material from 34 patients having bronchioloalveolar carcinoma has demonstrated two histopathologic types that have a bearing on the prognosis. Type 1 is associated with gross and microscopic mucus production, and is likely to be multicentric. Type 2 has lesser amounts of mucus, and is likely to be solitary. The 5-year survival of type 1 is 26%, and that of type 2 is 72%.

Histological subtypes or grading of pulmonary adenocarcinoma. A histochemical and electron microscopic study

To reveal whether the different histological subtypes of pulmonary adenocarcinoma are composed of different types of cells, we analyzed basic mucus histochemistry and ultrastructural features in a series of 61 adenocarcinomas correlating the findings with four ways of histological classification and grading. 82% of the tumours were composed of a single and 18% of two or more cell types. The original WHO classification had no association with the histochemical or ultrastructural features studied. A modified WHO classification, however, based on the prevailing subtype, had significant associations with five, a classification based on prevailing growth pattern with four, and histological grading with eight histochemical and electron microscopic features. The results suggest that it is more important to classify pulmonary adenocarcinomas by histological grades than by subtypes.

Papillary carcinoid tumor of the lung

Carcinoid tumors of the lung have a wide histologic spectrum. The histologic differential diagnosis of papillary tumors in the lung generally does not include carcinoid. A carcinoid tumor that formed a discrete coin lesion on chest radiograph is presented in this report. On gross examination the center appeared and felt spongy. On microscopic examination delicate, compacted papillae were separated by a serpentine space continuous with air spaces at the periphery of the tumor. The papillae were each composed of a fibrovascular core, an undulating basement membrane separating stroma from epithelial cells, and cuboidal clear and dark cells that proved to be, respectively, healthy and degenerate cells of carcinoid tumor with neurosecretory granules. Upon the carcinoid cells, draped in the manner of an umbrella, were nonciliated, respiratory cells that proved to be Clara cells. The various histologic patterns of bronchopulmonary carcinoids and the differential diagnosis of papillary tumors within the lung are tabulated.

Factors in the cytological diagnosis of alveolar cell carcinoma

Cytologic specimens of 23 patients suffering from histologically confirmed alveolar cell carcinoma (bronchiolo-alveolar carcinoma) were examined with respect to 47 objective and subjective criteria by two independent cytologists. The following characteristics were found: typical clustering of tumor cells (concretion = tightly packed cells, often finger-like packing or rosette-formation), hyperchromasia of the nucleus, size of tumor cells like or larger than alveolar macrophages, narrow ranges of nucleus-cytoplasm ratios (mean: 0.675; SD: 0.100) despite polymorphism of tumor cells, folding of the nuclear membrane, and signs of phagocytic activity (vacuolation, excentric position of the nucleus, erythrophagocytosis). A factor analysis of the results of examinations revealed six underlying factors of diagnosis. These factors are considered to be especially important for the validity of the diagnosis of a alveolar cell carcinoma and the occurrence of misinterpretations: yield of tumor cells in the specimen, type of clustering of the tumor cells degree of preservation, qualitative attributes of the nucleus, qualitative attributes of the cytoplasm, and quantitative measurements of the size of tumor cells.