Observations on bronchiolo-alveolar carcinomas with special emphasis on localized lesions. A clinicopathological, ultrastructural, and immunohistochemical study of 11 cases

Our plain-English summary of Observations on bronchiolo-alveolar carcinomas with special emphasis on localized lesions. A clinicopathological, ultrastructural, and immunohistochemical study of 11 cases, by C.A. Axiotis, T.A. Jennings (The American Journal of Surgical Pathology, 1988).

The study

• Authors: C.A. Axiotis, T.A. Jennings
• Journal: The American Journal of Surgical Pathology
• Published: 1988;12(12):918-31
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pathological and clinical features in early localized mucinous and nonmucinous bronchiolo-alveolar carcinomas (BAC) have not been adequately compared. In an attempt to characterize such lesions, we studied the clinicopathological, ultrastructural, and immunohistochemical features of three mucinous and eight nonmucinous BAC (four Clara cell, four Type II pneumocyte) along with one sheep pulmonary carcinoma (SPC). Tumor border, associated fibroplasia, tumor cell incohesion, lymphocytic infiltrate, T-lymphocytes, Langerhans cells (LC), and Leu-M1 and OC 125 immunoreactivity were evaluated. Localized tumors of both types had a similarly favorable prognosis, even when the tumor size was greater than 3 cm or showed more complex histology. Type II pneumocyte carcinomas with tumor cell disassociation and desquamation or a pseudomesotheliomatous phenotype did poorly. Clara cell and type II carcinomas elicited an LC and T-lymphocyte immune response. LC and T-lymphocytes were absent in mucinous BAC and SPC. All of the three mucinous and three of the seven nonmucinous BAC were Leu-M1 negative, indicating that Leu-M1 may not distinguish between BAC and mesothelioma, especially in a small biopsy specimen. Tumors with absent or slight Leu-M1 immunoreactivity had a favorable outcome irrespective of cell type and presence or absence of LC. Inasmuch as OC 125 was negative in all cases of BAC, OC 125 may be a useful adjunct in the immunodiagnosis of mesothelioma. Our investigation supports the view that two different groups of tumors are assembled under the single nosologic entity of BAC: one, mucinous, which grows along an unaltered pulmonary alveolar framework and elicits a B-lymphocytic response, and the other, nonmucinous, which induces desmoplasia and elicits an LC and T-lymphocytic response. Only mucinous BAC represent a biologic entity distinct from conventional pulmonary adenocarcinomas.

In plain English

This was a laboratory and clinical study of 11 cases of bronchiolo-alveolar carcinoma (BAC), a type of lung cancer, from the Yale University Department of Pathology, plus one sheep lung tumor. It did not study asbestos. It discussed telling BAC apart from mesothelioma: one case mimicked mesothelioma, and the authors tested stains used to distinguish lung cancer from mesothelioma. Three tumors were mucinous and eight nonmucinous (four Clara cell, four Type II pneumocyte). Localized tumors generally did well. One Type II pneumocyte carcinoma (case 11) spread only over the pleural surface, imitating malignant mesothelioma. The Leu-M1 stain was negative in all three mucinous tumors and in three Clara cell tumors. The authors concluded that a negative Leu-M1 stain does not rule out adenocarcinoma, especially in a small biopsy. The OC 125 stain was negative in all BAC cases. The authors suggested OC 125 may be a useful aid in distinguishing BAC from malignant pleural mesothelioma. They noted that the small number of cases made it difficult to judge how Leu-M1 staining and Langerhans cells related to outcome.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case series: clinicopathological, ultrastructural (electron microscopy) and immunohistochemical study of 11 cases
• Who was studied: 11 patients with bronchiolo-alveolar carcinoma: 10 found by reviewing surgical pathology material at the Yale University Department of Pathology (accessioned 1975 to 1982) and 1 autopsy case. One sheep pulmonary carcinoma (jaagsiekte) was also examined.
• Exposure: Not an exposure study. The article does not examine asbestos or any occupational exposure. Smoking history was noted where available.
• Main results:
  • Mucinous BAC (3 patients, all Stage I, treated by lobectomy): one patient (case 1) died of pneumonia after surgery, and autopsy showed no residual carcinoma. The other two were alive with no evidence of disease 36 and 132 months after surgery.
  • Clara cell carcinomas (4 patients, all Stage I): three were alive with no evidence of disease 36 to 52 months after surgery. One (case 7) died 16 months after surgery, disease status unknown.
  • Type II pneumocyte carcinomas: two patients died with disease at 7 and 10 months. The authors reported that the only localized tumors that did poorly were Type II pneumocyte carcinomas showing tumor cell disassociation and desquamation.
  • Case 11, a Type II pneumocyte carcinoma, spread only over the pleural surface without a tumor focus inside the lung, mimicking mesothelioma. The authors described it as the first documented pseudomesotheliomatous carcinoma of Type II pneumocytes.
  • Leu-M1 staining: all three mucinous tumors were negative. Three Clara cell carcinomas were negative and one showed 1+ staining. Two Type II pneumocyte carcinomas showed 3+ staining and one showed 2+. The authors concluded that absent Leu-M1 staining does not absolutely rule out adenocarcinoma, especially in a small biopsy specimen.
  • OC 125 staining was negative in all the BAC cases. The authors added an observation of their own outside this case series: three cases of malignant mesothelioma showed multifocal OC 125 staining.
  • Clara cell and Type II pneumocyte carcinomas contained numerous Langerhans cells and T-lymphocytes. Mucinous BAC lacked a Langerhans cell infiltrate, and none were found in the sheep pulmonary carcinoma.
• The authors' conclusion: The authors concluded that two different groups of tumors are grouped under BAC (mucinous and nonmucinous). They concluded that early localized tumors of both types have a similarly favorable prognosis, and that OC 125 may be a useful aid in distinguishing BAC from malignant pleural mesothelioma.
• Limitations the authors state:
  • Because of the few cases, the relationship of Leu-M1 positivity and Langerhans cell infiltration to prognosis was difficult to assess.
  • No early localized mixed-type BAC were present in the series.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Carcinoma, Prognosis, Histology, Mesothelioma, Biopsy, Adenocarcinoma.

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