Bronchiolo-alveolar carcinoma. A reappraisal after 24 years

Comparative Characteristics of Napsin A, TTF 1 and EGFR Mutation Expression in Mucinous Lung Cell Carcinomas

BACKGROUND

Invasive mucinous lung adenocarcinomas are rare and account for 2%-10% of all lung adenocarcinoma cases. It is believed that Napsin A exhibits a weaker expression in mucinous adenocarcinomas compared with TTF1, but such correlation is still poorly researched.

AIM

The aim of the study was to determine the frequency of mucinous to nonmucinous adenocarcinomas and compare specificity and sensitivity of monoclonal Napsin A with TTF1 in mucinous adenocarcinomas and define the frequency of EGFR mutations.

MATERIALS AND METHODS

Eighty-four resected lung carcinomas were prospectively evaluated. All biopsies were analysed with p63, TTF1, monoclonal Napsin A, CK7, CK20 and CDX2 and were studied with real-time PCR technology.

RESULTS

In resected material we detected 49/84 (58.3%) adenocarcinomas and selected 21 mucinous adenocarcinomas out of 46 non-mucinous adenocarcinomas (45.6%). The most common pattern of mucinous adenocarcinomas is papillary - 24% and colloidal - 24%, followed by acinar - 19.2% and lepidic - 19.2%. mNapsin A was positive in 18/21 (85.7%) mucinous adenocarcinomas v/s 17/21 TTF1 positive (80.9%). EGFR mutations were detected in 3/21 cases with mucinous adenocarcinomas (14.3%): mucinous papillary, mucinous acinar and "salivary gland-like".

CONCLUSION

Our study demonstrates a high proportion of primary mucinous lung adenocarcinomas to primary non-mucinous adenocarcinomas. Sensitivity and specificity of mNapsin A and TTF1 did not show significant difference in pulmonary mucinous and non-mucinous adenocarcinomas, as mNapsin A gave greater sensitivity to mucinous adenocarcinomas. Our results indicate the same mutation frequency of EGFR in mucinous adenocarcinomas as mutation frequency detected in non-mucinous adenocarcinomas in the Bulgarian region.

Reclassification of early stage pulmonary adenocarcinoma and its consequences

The classification of pulmonary adenocarcinoma has recently undergone several proposed changes. Among these, the most striking pertains to the discontinuation of the term "bronchioloalveolar carcinoma (BAC)" and its replacement by the terms "adenocarcinoma in situ (AIS)" or "minimally invasive adenocarcinoma (MIA)" for small solitary adenocarcinomas with either pure bronchiolalveolar growth or predominant bronchioloalveolar growth and ≤5 mm invasion, respectively, in resection specimens. The recommendation for these new concepts was based on discussion and review of the literature by a panel of experts from multiple disciplines. However, the results of a recent study investigating the topic of early stage adenocarcinoma (pT1N0M0) which was based on an actual series of cases, have raised questions as to the concept, validity and justification of such new terminology and have reinforced the need to evaluate actual cases that meet the newly proposed definitions and compare them in terms of patient outcome. This is even more important when proposing terminology that implies benign behavior and that could result in a false sense of security putting patients at risk for suboptimal treatment approaches. The controversies surrounding these issues are the subject of this work.

Pulmonary adenocarcinoma T1N0M0 and its classification

Over the last decade, use of the term bronchioloalveolar carcinoma (BAC) has come under constant scrutiny as some consider it an anachronism or a term that provides incorrect information about this neoplasm. To that extent, it has recently been suggested to replace the term BAC with that of in situ adenocarcinoma (AIS) or minimally invasive adenocarcinoma (MIA) for small solitary adenocarcinomas with either pure bronchioloalveolar growth (AIS) or predominant bronchioloalveolar growth and ≤5-mm invasion (MIA). However, as of today, there is no comprehensive study of these tumors, and most of what has been published in this context is based on a review of the literature that focused on scattered short series of cases describing either small adenocarcinomas or BAC. More recently, a large series of cases of a more comprehensive nature that included all early-stage adenocarcinomas (T1N0M0) has cast some doubt regarding the need for the proposed change in nomenclature. At the same time, it was suggested that if indeed that notion is maintained, a more serious and comprehensive study of actual cases must be undertaken. The details of the issues surrounding this subject are presented in this review.

A favorable response to cisplatin, pemetrexed and bevacizumab in two cases of invasive mucinous adenocarcinoma formerly known as pneumonic-type mucinous bronchioloalveolar carcinoma

The leading subtype of lung cancer, adenocarcinoma, received a new classification in 2011 when multifocal, pneumonic-type mucinous tumors, formerly called mucinous bronchioloalveolar carcinomas, were reclassified as "invasive mucinous adenocarcinomas." These tumors appear to be less sensitive to chemotherapy than other non-small cell lung cancers. We herein report two cases of invasive mucinous adenocarcinoma that showed a dramatic radiologic response to combination therapy with cisplatin, pemetrexed and bevacizumab. Recent data suggest that the use of paclitaxel-based chemotherapy is an acceptable therapeutic strategy in cases of invasive mucinous adenocarcinoma. The cases reported here and preclinical findings suggest the therapeutic efficacy of cisplatin, pemetrexed and bevacizumab in treating such tumors.

Advanced bronchioloalveolar carcinoma: a phase II trial of paclitaxel by 96-hour infusion (SWOG 9714): a Southwest Oncology Group study

BACKGROUND

There are no published prospective trials of chemotherapy for advanced bronchioloalveolar carcinoma (BAC), a subtype of non-small-cell lung cancer for which there is no current standard therapy. This phase II study assesses the efficacy and toxicity of 96-h paclitaxel in chemotherapy-naive patients with advanced BAC.

PATIENTS AND METHODS

Patients with histologically confirmed stage IIIB (with pleural effusion) or stage IV BAC were eligible. Treatment consisted of paclitaxel 35 mg/m2/24 h continuously infused over 96 h (days 1-4) every 21 days for up to six courses.

RESULTS

A total of 58 eligible patients were enrolled. The objective response rate was 14% (all partial responses, 9% confirmed); 40% of patients demonstrated stable disease. The median progression-free and overall survivals were 5 and 12 months, respectively. Grade 3 or greater toxicities included neutropenia/granulocytopenia (43%), febrile neutropenia (12%), infection (22%), and stomatitis/pharyngitis (10%); there were five treatment-related deaths.

CONCLUSIONS

S9714 represents the first prospective multi-institutional cooperative group trial focusing on treatment outcomes in BAC. Studies targeting this population are feasible, and while first-line paclitaxel administered as a prolonged infusion is active in this setting, toxicities limits the utility of this regimen. S9714 serves as a historical control for BAC patients against which future therapeutic approaches can be compared.

Cytologic approach to tumors of the tracheobronchial tree

Cytologic testing is an integral part of the workup of patients suspected of having lung cancer. These tests are less invasive than other tissue procurement methods, with minimal risk of complications. In experienced hands, the tests are highly accurate and reliable. To achieve good results and avoid diagnostic errors, clinicians must be educated in proper collection and fixation methods and the pathologist should be cognizant of clinical and radiologic data. Close communication between the clinician and pathologist should be encouraged.

Genetic and immunologic therapies for lung cancer

The poor overall survival of lung cancer patients treated with conventional therapies (chemotherapy, radiation therapy, and surgery) mandate novel approaches to treatment. Two novel approaches to treat lung cancer include gene therapy and immunologic therapy. Both treatments have preclinical data suggesting potential clinical use. In gene therapy, the identification of specific genes critical to the development of carcinogenesis has offered the opportunity to target these genes or their products for treatment. One possible gene therapy strategy that has been pursued in phase I and II lung cancer trials is to replace nonfunctional tumor suppressor genes such as mutated or deleted p53 genes with wild-type p53 genes by adenoviral gene transfer (Ad-p53). Transduction of the tumors has been accomplished with direct intratumoral injection or broncheoalveolar lavage. These studies have identified a potential role for radiosensitization of previously radiation-resistant local tumors by combining Ad-p53 with radiation or possibly chemoradiation. Another novel strategy that may allow systemic treatment of lung cancers is immunologic therapies. Immunotherapies have focused on augmenting the immune response to cancer by passive strategies (e.g., antivascular endothelial growth factor) or active nonspecific (e.g., interferon), or by specific (e.g., anti-idiotype therapy) strategies. These novel strategies are currently in clinical trials and will potentially allow additional therapeutic options for patients resistant to conventional therapies.

Bronchioloalveolar carcinoma of the lung: recurrences and survival in patients with stage I disease

OBJECTIVES

The aim of our study was to retrospectively compare the patient characteristics, the frequency and pattern of recurrent disease, and survival in patients with stage I bronchioloalveolar carcinoma and adenocarcinoma of the lung.

METHODS

Patients with stage I bronchioloalveolar carcinoma or adenocarcinoma other than bronchioloalveolar carcinoma resected between 1984 and 1992 with adequate clinical follow-up were studied. The clinical characteristics of the patients, extent of initial surgical resection, sites of recurrent disease, and overall survival were examined and compared between the 2 groups. The median follow-up for patients with bronchioloalveolar carcinoma and adenocarcinoma was 6.2 years and 5.9 years, respectively.

RESULTS

A total of 138 patients were identified. Thirty-three patients had bronchioloalveolar carcinoma and 105 patients had adenocarcinoma. Eleven (33%) of the patients with bronchioloalveolar carcinoma had never smoked cigarettes versus 9 (9%) of the patients with adenocarcinoma (P =.0036). There were no significant differences between patients with bronchioloalveolar carcinoma and adenocarcinoma in sex distribution and overall recurrence rate. Of the 12 patients with recurrent bronchioloalveolar carcinoma, 1 patient (8%) had extrathoracic disease develop at the site of first recurrence compared with 49% of patients with recurrent adenocarcinoma (P <.001). The 5-year survival in patients with bronchioloalveolar carcinoma and in those with adenocarcinoma was 83% and 63%, respectively (P =.04).

CONCLUSIONS

Stage I bronchioloalveolar carcinoma is more likely to occur in nonsmokers. Survival is longer in patients with bronchioloalveolar carcinoma. Further research is warranted to define the etiology, clinical course, and molecular abnormalities in patients with bronchioloalveolar carcinoma to generate more effective therapeutic approaches.

Multiple papillary adenomas of type II pneumocytes found in a 13-year-old boy with von Recklinghausen's disease

A case of multiple papillary adenomas of type II pneumocytes is reported. A 13-year-old boy with von Recklinghausen's disease had small nodular lesions in both lungs without symptoms. The biopsied lung contained greyish-white nodules ranging in size from 0.5 to 2 mm. Light microscopic examination revealed cuboidal to low columnar cells arranged in a papillary pattern. Elastic fibres were present in the tumour stroma. Electron microscopically, the cells had osmiophilic lamellar bodies in the cytoplasm and short microvilli along the free border. The tumour cells expressed immunoreactivity for epithelial membrane antigen and surfactant apoprotein antibodies. More than 6 years after open lung biopsy, the patient is well but small nodular shadows can still be identified.

Metastatic bronchioloalveolar carcinoma and metastatic adenocarcinoma of the lung: comparison of clinical manifestations, chemotherapeutic responses, and prognosis

Between 1975 and 1985, 25 patients with metastatic bronchioloalveolar carcinoma and 223 patients with metastatic adenocarcinoma of the lung received experimental cisplatin-based chemotherapy at the Mayo Clinic. The chemotherapeutic response rates were 32% and 33%, respectively. The median times to progression of disease were identical (3 months in both groups). The median survival times were 4 months and 6 months, respectively. Metastatic bronchioloalveolar carcinoma is an aggressive disease that is associated with a poor prognosis, similar to metastatic adenocarcinoma of the lung.

The changing pattern of lung carcinoma

In a study of 505 cases of lung carcinoma from a period in which there was a significant change in tobacco-smoking habits, a dramatic shift in the histologic type and location of the lung tumors was observed. Peripheral tumors, found in 30.7% of the carcinomas occurring before 1978, were found in 42% of the carcinomas from 1986 to 1989. The corresponding decrease in the centrally originating bronchial carcinoma was from 69.3% to 57.3%. The greatest change in histologic cancer type was that the incidence of bronchioloalveolar carcinoma more than doubled from 9.3% in the earlier period to 20.3% percent in the 1986-to-1989 period. Corresponding to the decreasing incidence of lung carcinoma, there is a decrease in cancers related to cigarette smoking. A study of cases of lung carcinoma among nonsmokers and former smokers showed a decreased incidence of the bronchogenic cancers and an increase of cancer occurring in the peripheral lung parenchyma. This finding should be validated in other population-based studies, and if confirmed, new studies should be undertaken in an attempt to discover the factors that play a role in the development of such cancers. As an example, viral oncogenes may be a possibility. Viruses were suggested in the past as being related to the development of some of these tumor types.

Bronchioloalveolar carcinoma

It is helpful to consider BAC as two distinct clinical entities. The solitary or focal form presents as a well circumscribed pulmonary nodule, tends to remain localized with slow growth, and has an excellent prognosis following resection. While it may progress to diffuse disease, this is distinctly unusual and is only supported by Hill's study in the literature. It may metastasize to regional lymph nodes or to distant sites not unlike other carcinomas of the lung, although the incidence of metastatic disease is quite low. The diffuse form of BAC, recognizable as multiple nodules or consolidation, represents an aggressive malignancy with limited survival regardless of intervention.

Alveolar cell carcinoma of the lung: a retrospective analysis of 205 patients

From 1970 to 1986, survival of 205 patients with alveolar cell carcinoma was retrospectively studied. Analysis examined the predictive value of presenting symptoms and diagnostic screening results for pathological Stage III or IV disease (advanced) and survival. The lesion presented as a peripheral mass in 121 patients (59%) and as an infiltrate in 84 (41%). Follow-up data were available on 199 patients (97%). Variables analyzed included indices of background or risk factors, presenting symptoms, diagnostic test results, and clinical management. Seventy-nine patients (39%) had a histological diagnosis of advanced disease by TMN staging criteria. Of the 152 deaths (74%), 117 (77%) were related to the pulmonary carcinoma. Univariate analysis associated short-term and long-term anorexia, weight loss, generalized weakness, and profound dyspnea with advanced disease and ultimately with death due to cancer. Multivariate logistic regression analyses suggested that weight loss and dyspnea disclosed independent information about the likelihood of advanced disease for this population (p less than 0.0003). Cox proportional hazard regression analyses of survival revealed a significant association between weight loss and death due to alveolar cell carcinoma after pathological stage was taken into account (p = 0.001). In this series, the 80 patients with Stage I disease had the best prognosis (5-year survival of 55%). There was no significant difference in disease-free survival between patients having wedge resection (N = 17) and those having lobectomy (N = 63) for Stage I disease.

Cytologic diagnosis of bronchioloalveolar carcinoma by fine-needle aspiration biopsy

From 1970 to June 1984, 275 patients with bronchioloalveolar carcinoma were admitted to the Toronto General Hospital. Of these, 181 (190 aspiration biopsies, including nine repeat samples) had this diagnosis made following the use of transthoracic fine-needle aspiration biopsy. Based on the cytomorphologic features observed in the aspiration preparations, the tumor was subclassified into three types: nonsecretory, secretory, and poorly differentiated. The cytologic features of these three types of bronchioloalveolar carcinoma are presented and illustrated. Cytomorphologically, the three types of this tumor are distinctly different and their features are sufficiently distinctive from those of bronchogenic adenocarcinoma and metastatic adenocarcinomas to be of diagnostic value. Transthoracic fine-needle aspiration biopsy appears to be a definitive minimally invasive means of establishing the diagnosis of bronchioloalveolar carcinoma preoperatively and especially to be of value for those small peripheral cancers which are relatively inaccessible to direct method of study and are potentially surgically curable.

Bronchioloalveolar carcinomas. Cell types, patterns of growth, and prognostic correlates

Forty-five bronchioloalveolar carcinomas were studied, including 27 cases by electron microscopy. Bronchioloalveolar carcinomas can be classified by routine sections or by diastase-digested periodic acid-Schiff (PAS) stains, but electron microscopy is useful in confirming Clara cell or type II pneumocyte (nonmucinous) differentiation and excluding metastases. Mucinous bronchioloalveolar carcinoma can mimic metastatic adenocarcinoma histologically and ultrastructurally. Of the nine tumors with mucinous differentiation, eight had aerogenous dissemination (multifocal or with pneumonic spread), and seven of those eight were fatal. Twenty-four of 36 nonmucinous bronchioloalveolar tumors had aerogenous spread; all of the 24 patients died or were living with distant metastases. The 12 nonmucinous tumors without aerogenous dissemination had a 5-year survival rate of 61%. Among these, the smaller tumors had a better prognosis. The presence of alveolar spread, rather than cell type, was the most important feature predicting survival.

Relation of fine structure to prognosis for papillary adenocarcinoma of the lung

Eight cases of papillary adenocarcinoma of the lung were investigated by light and electron microscopy. Prognoses for all but one patient were favorable. Two patients (husband and wife) who underwent tumor resection during the same year experienced no disease-related problems for more than seven years afterward. Microscopic study of the papillary adenocarcinomas revealed columnar, peg-shaped, mucus-secreting tumor cells lining the alveoli. The tumor tissue contained alveolar macrophages, with some multinucleated giant cells, interstitial lymphoid infiltrates, mildly thickened alveolar walls, and a few pneumoconiotic foci. These inflammatory stromal reactions in the tumor tissue might have been associated with the favorable prognoses. Nuclear inclusions were detected in some tumor cells in all cases. Ultrastructurally, the inclusions contained tubular, granular, crystalline, and electron-dense homogeneous structures in addition to unclassifiable nuclear bodies. The tubular structures were in close proximity to inner leaflets of the nuclear membranes. The papillary adenocarcinoma cells had features of totipotential bronchioloalveolar cells, differentiating toward type II pneumocytes, Clara cells, and ciliated epithelial cells.

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%.

Ultrastructure of neoplastic cells in different histologic subtypes of pulmonary adenocarcinoma

57 pulmonary adenocarcinomas were classified according to the WHO Classification of Lung Tumours. 55 cases were primary adenocarcinomas and two were metastases from the gastrointestinal tract. The acinar, papillary and bronchiolo-alveolar carcinomas were well or moderately differentiated and the solid adenocarcinomas were poorly differentiated tumours secreting mucus in intracytoplasmic vacuoles. All tumours, including the two metastases, were analyzed by transmission electron microscopy. Most of the acinar, papillary and all bronchiolo-alveolar adenocarcinomas contained a great or moderate number of secretory granules which were pale fibrillar or dense homogeneous. Among the solid adenocarcinomas there were no tumours with a great number of secretory granules. The surface fine structure of the metastatic carcinomas differed from those of the primary adenocarcinomas, having a brush-border instead of microvilli. The ultrastructure of the primary adenocarcinomas resembled the normal surface epithelial cells of bronchi and bronchioli, and two papillary adenocarcinomas contained lamellar bodies similar to granular pneumocytes. Instead of dividing into four different subtypes pulmonary adenocarcinomas can be classified according to histological grading.

Metastatic carcinoma masquerading as scleritis

A 36-year-old white man abruptly developed painless visual loss in his left eye. Fundoscopic evaluation revealed a shallow left superotemporal retinal detachment with an underlying yellowish choroidal infiltrate. Fluorescein angiography disclosed indistinct choroidal leakage, and both B-scan ultrasonography and computed tomography demonstrated superotemporal thickening of the choroid and the sclera. The patient was diagnosed clinically as having a scleritis and an associated exudative retinal detachment. He was placed on a several months' course of systemic prednisone, and despite this regimen, his condition worsened with the appearance of severe pain, proptosis and displacement of the eye, glaucoma, and intense episcleral and scleral injection. The eye was enucleated and displayed externally a massively thickened sclera superotemporally. Light microscopic evaluation of the enucleated globe revealed an extensively necrotic tumor growing diffusely within the choroid; infiltrating viable tumor cells were discovered within the sclera and episclera. The tumor cells had the characteristics of a well-differentiated, mucin-producing adenocarcinoma. Electron microscopic studies demonstrated lumen-forming tumor cells with apical villi, cytoplasmic pseudolumens, pools of cytoplasmic glycogen, and multiple types of inclusions, including mucin, lipid, and electron-dense secretory granules similar to those in pulmonary Clara cells. These findings were consistent with a bronchiolo-alveolar carcinoma. The patient subsequently developed bilateral reticulo-nodular pulmonary infiltrates, also typical of this tumor. The unusual clinical features of this case of "malignant scleritis" are discussed in light of the final diagnosis.

Alveolar-cell carcinoma: a problem in sputum cytodiagnosis

Cytology and histology are correlated in a series of 22 cases chosen to illustrate the differential diagnosis between clusters of benign bronchial or bronchiolar cells seen in sputum, and those of alveolar cell carcinoma or adenocarcinoma with alveolar spread. Alveolar-cell carcinoma is characterised by clusters of small epithelial cells in spherical or irregular formations, none showing enough polarity to distinguish a smooth or palisaded surface. The appearances are most distinctive if vacuolation is absent. The diagnosis cannot, however, be confidently made in all cases from morphological features of cells in sputum.

Ultrastructural markers of colonic adenocarcinoma

A mixed population of 96 adenocarcinomas was examined by electron microscopy to establish the presence of organ specific features. This resulted in the identification of fine structural characteristics, occurring consistently in colorectal adenocarcinomas but not in other epithelial tumors. The colorectal "ultrastructural profile" consists of microvilli with dense cores of microfilaments extending as long rootlets into a clear zone of apical cytoplasm, apical electron dense bodies, and abundant glycocalyceal bodies. Of these features, the long rootlets constitute the best morphologic marker for large intestinal type adenocarcinoma. Using these characteristics in another series of 58 adenocarcinomas studied in a double-blind manner, it was possible to distinguish colorectal adenocarcinomas from other carcinomas on ultrastructural grounds alone.

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.

Focal increased lung perfusion and intrapulmonary veno-arterial shunting in bronchiolo-alveolar cell carcinoma

A patient with bronchiolo-alveolar cell carcinoma presented with a veno-arterial shunt localized to the area of tumor involvement by differential position shunt testing. Perfusion lung scan revealed increased radionucleotide uptake in the area of the tumor, confirmed by pulmonary angiography, and suggested that the primary blood supply to the tumor was originating from the pulmonary circulation. Surgical resection of the tumor resulted in marked reduction of the intrapulmonary shunt.

Bronchiolo-alveolar carcinoma: a correlative clinical and cytologic study

From 1970 to 1977, 101 patients with bronchiolo-alveolar carcinoma were admitted to the Toronto General Hospital. Cytology preparations from 97 patients were reviewed and analyzed in correlation with biologic behavior of the tumours. The value of cytologic diagnosis was reassessed. It appears that routine cytology methods were of limited value in the investigation of patients with a peripheral solitary tumor and therefore, percutaneous fine needle aspiration with positive results in 92% of cases examined, was the only useful cytologic examination for this type of lesion. For multicentric tumors, routine cytology methods achieved positive results in 87.9% of cases and fine needle aspiration 100%. Based on cytomorphologic features, bronchioloalveolar carcinoma can be subclassified into three types: secretory, nonsecretory and poorly differentiated. In this series, 84% of solitary tumors were secretory or nonsecretory type with favorable prognosis, and 16% of solitary tumors were poorly differentiated type with poor prognosis. 55.2% of multicentric tumors were poorly differentiated type and 77.3% of multicentric tumors showed positive lymph nodes at surgery. Our results demonstrate that patients with multicentric or poorly differentiated tumors had poor prognosis.

Bronchioloalveolar cell carcinoma of the lung: a clinicopathological study

Thirty-nine patients with bronchioloalveolar carcinoma were reviewed. The primary lung tumor from 27 patients was examined and divided by histological criteria into three categories. The type 1 pattern was associated with a mean survival of 4.7 years. A mean survival of 3.8 years was attained in patients with type 2. Patients with the type 3 pattern had an average survival of 1.4 years. There was a statistically significant difference in survival when types 1 and 2 together were compared with type 3 (rho less than 0.05). Another statistically significant finding was a mean survival of 5.2 years in patients with negative lymph nodes after surgical resection and a 2.2 year mean survival in patients with positive nodes. The tumor histology of bronchioloalveolar carcinoma should be examined carefully to obtain helpful information in predicting survival. We recommend that these tumors be classified as well-differentiated or poorly differentiated bronchioloalveolar carcinoma.

Reappraisal of solitary bronchiolar (alveolar cell) carcinoma of the lung

Twelve patients with solitary bronchiolar carcinoma had lobectomy and were followed for up to 16 years. The concept of a multicentric origin of bronchiolar carcinoma, maintained for more than eight decades, should be discarded. The neoplasm arises indolently and usually in an area of pulmonary fibrosis. After lobectomy patients can now expect to follow one of four courses: (1) to be alive and well without recurrence; (2) after several years to have pulmonary recurrence or a new carcinoma; (3) with minute spread at the time of lobectomy to have metastasis develop in a short period; or (4) to die of unrelated conditions. The overall 5-year survival with this tumor is about 75%. Late recurrence or the development of another primary tumor, however, prompts the need for prolonged follow-up. Immunologically, patients have circulating antibodies when well and demonstrable circulating antigens with recurrence. The survival rate of selected patients with solitary bronchiolar carcinoma (eliminating those patients with microscopic spread from the primary neoplasm at the time of resection and those dying of other causes) was 100% after 5 years and 75% after 10 years.

Glycogen-rich Clara cell-type bronchiolo-alveolar carcinoma: light and electron microscopic study

A clear cell type of bronchiolo-alveolar carcinoma removed from the lung of a 63-year-old man was studied by light and electron microscopy. The tumor was composed exclusively of Clara cells identified by the presence of secretory granules, an abundance of granular endoplasmic reticulum, a moderate number of mitochondria and prominent Golgi complexes. The tumor cells were tall columnar and had clear cytoplasm due to the presence of large pools of intracytoplasmic glycogen. This feature has not heretofore been described. Ultrastructural features distinguishing this tumor from benign clear cell tumors of the lung and clear cell carcinomas of the kidney are described.

Preferred surgical treatment for alveolar cell carcinoma

An analysis of our experience with 48 patients having bronchiolar or alveolar cell carcinoma is reported. The remarkable biological variability of this peripheral tumor has important surgical implications. Basically, two dominant clinical presentations occur. In the less common diffuse or multinodular form, prolonged survival is infrequent regardless of the therapeutic approach. Often these patients die from respiratory compromise due to the tumor itself. In the more common localized or solitary form the prognosis for cure is good, approximating 47% or higher. Based on the material presented, lobectomy is the preferred method of surgical treatment. In patients manifesting multinodular disease, surgical resection rarely seems warranted. The concept of preserving pulmonary tissue is stressed.

Ultrastructure of human bronchiolo-alveolar cell carcinoma

Ultrastructural features were correlated with a series of special staining reactions in eight cases of bronchiolo-alveolar carcinoma. Ultrastructural, all tumors were similarly composed of large cells with abundant cytoplasm and small nuclei in close contact with each other. Straight membranes or complex interdigitations occurred within adjacent tumor cells, attached to each other by scattered desmosomes. Microvilli or cilia abutted from free surfaces of the cells, and were noted in different stages of evolution. Numerous organelles were seen in the cytoplasm, including prominent mitochondria and single or coalescent secretory vacuoles with granular matrix resembling mucin. Other cytosomes less commonly found were irregular, partially lamellated inclusions and dark, homogeneous structures without limiting membranes. The stroma of the tumors was rich in elastin and collagen. Both the number of secretory vacuoles in the cytoplasm of tumor cells and the amount of connective tissue fibrils in the stroma of the tumors correlated well with the findings in the series of special staining reactions. No definite ultrastructural feature was present to identify the tumors as orginating from Type II alveolar epithelial cells, but the possibility exists that they arose in the bronchiole, from undifferentiated basal cells or mucinous cells per se. Our impression in these eight cases studied is consistent with the view that bronchiolo-alveolar carcinomas are indistinguishable at the ultrastructural level from other bronchogenic adenocarcinomas.