Until recently, bronchioalveolar carcinoma (BAC) encompassed various premalignant lesions of pulmonary adenocarcinoma that develops from the epithelium of the terminal bronchioles and their acini at the peripheries of the lung and was distinguished by the absence of blood vessel or pleural involvement (also known as lepidic growth) [1] [2]. Because of its poor histological and radiographic specificity, bronchioalveolar carcinoma was recently replaced with the terms pulmonary adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA), with mucinous, non-mucinous and mixed forms as subtypes of both lesions [2] [3] [4] [5] [6]. In addition, subtypes of invasive adenocarcinoma (lepidic predominant adenocarcinoma - LPA, and invasive mucinous adenocarcinoma) are also terms that have arisen from BAC [3]. One of the most important features of BAC is that its clinical presentation, comprised of a cough, chest pain and the production of sputum, can have a broad differential diagnosis (infections, hypersensitivity pneumonitis, etc.) [1]. The absence of fever, however, which is never seen in BAC, should point toward a noninfectious etiology [1]. Unfortunately, more than 60% of patients have no apparent symptoms, thus the diagnosis might be difficult to make [1]. But because BAC is a premalignant lesion and because 5-year survival rates are 100% if appropriate therapy is implemented early on, usually in the form of surgical resection, recognition of these lesions is vital in limiting its progression to a malignant tumor, which then carries a significantly poor prognosis regardless of the stage [6] [7].

• Fever

  The most frequent symptoms and signs are cough, sputum, shortness of breath, weight loss, hemoptysis, and fever. Bronchorrhea is unusual and a late manifestation. [ncbi.nlm.nih.gov]

• Fatigue

  Grade 3 diarrhea and fatigue were noted in three and five patients, respectively. [ncbi.nlm.nih.gov]

  Paraschiv and partners published a case in the Letters to the Editor section. 1 These authors describe a case of a male, 35-year smoker with a 35 pack-year history, consulting with symptoms of fatigue, cough and chest pain of 2-week duration. [archbronconeumol.org]

  Since they are located in the outer regions of the lungs away from the airways, however, these "typical symptoms" may be less common, and symptoms such as shortness of breath with exertion or profound fatigue may first be noted. [verywellhealth.com]

• Cough

  Two Japanese females complained of cough and bronchorrhea for which chest radiographs showed infiltrate in the lungs. The patients were subsequently diagnosed as having bronchioloalveolar carcinoma by transbronchial lung biopsy. [ncbi.nlm.nih.gov]

  The most frequent symptoms and signs are cough, sputum, shortness of breath, weight loss, hemoptysis, and fever. Bronchorrhea is unusual and a late manifestation. [radiographics.rsnajnls.org]

• Pleural Effusion

  PATIENTS AND METHODS: Patients with histologically confirmed stage IIIB (with malignant pleural effusion) or stage IV adenocarcinoma with BAC features or pure BAC were eligible. [ncbi.nlm.nih.gov]

  No pleural effusions or evidence of mediastinal adenopathy. Sputum, right and left main bronchus lavage were positive for malignant cells consistent with carcinoma. [radiopaedia.org]

  Prevalence and incidence of benign asbestos pleural effusion in a working population. JAMA 1982;247:617-622. ‎ [books.google.it]

  effusion OR pleural tumor foci that are separate from direct pleural invasion by the primary tumor], any N, M0) Stage IV disease (any T, any N, M1 [distant metastases present]) Recurrent disease in a separate lobe after prior resection within the past [clinicaltrials.gov]

  Secondary findings of BAC were hilar and mediastinal lymphadenopathy, pleural effusion, atelectasis and pneumothorax. Hilar and mediastinal lymphadenopathy appeared frequently(43.3%). 7. [ir.ymlib.yonsei.ac.kr]

• Dyspnea

  A few months later, their bronchorrhea and dyspnea worsened, and they were then treated with gefitinib, a selective epidermal growth factor receptor tyrosine kinase inhibitor. [ncbi.nlm.nih.gov]

• Productive Cough

  She just mentioned productive cough since about 6 months ago. History taking revealed neither inhalation exposure nor hemoptysis. Weight loss was about 15 kg during recent 3 months. [advbiores.net]

  She gradually developed productive cough and dyspnea since July 2001. Chest CT on June 25, 2002 revealed multiple pneumonia-like consolidations on each lobe of the right lung (Fig. 1 ). [wjso.biomedcentral.com]

  cough with bronchorrhea and/or dyspnea caused by “shunting” of blood. [hematologyandoncology.net]

• Chronic Cough

  When they finally appear, the signs are often less obvious than other forms of lung cancer, manifesting with a chronic cough and bloody sputum only in later, more advanced stages. [verywellhealth.com]

  Ming‐ran Xie, Yong‐fu Zhu, Mei‐qi Zhou, Sheng‐bing Wu, Guang‐wen Xu, Shi‐bin Xu and Mei‐qing Xu, Analysis of factors related to chronic cough after lung cancer surgery, Thoracic Cancer, 10, 4, (898-903), (2019). [doi.org]

• Pelvic Mass

  Four years later, she complained of vaginal bleeding, and a pelvic mass was discovered by an abdominal computerized tomography scan. Tumor debulking and total hysterectomy with bilateral salpingo-oopherectomy were performed. [ncbi.nlm.nih.gov]

• Long Arm

  Notably, the breakpoint at band q13 in the long arm of chromosome 5 is the same as we observed in a constitutional pericentric inversion previously reported in a patient with a pure GGO lesion ( 12 ). [doi.org]

• Vaginal Bleeding

  Four years later, she complained of vaginal bleeding, and a pelvic mass was discovered by an abdominal computerized tomography scan. Tumor debulking and total hysterectomy with bilateral salpingo-oopherectomy were performed. [ncbi.nlm.nih.gov]

• Meningism

  Following the cytologic diagnosis of carcinomatous meningitis (metastatic adenocarcinoma), an open lung biopsy was performed, which confirmed the presence of a primary pulmonary neoplasm (bronchioloalveolar carcinoma). [ncbi.nlm.nih.gov]

Premalignant lesions of the lungs can only be detected with a comprehensive approach, starting with a detailed patient history and a complete physical examination that could possibly identify an ongoing pathological process in the lungs. As signs and symptoms are often lacking, however, imaging studies, a full laboratory workup, and pathohistological evaluation are necessary steps. The absence of leukocytosis in the presence of respiratory symptoms can often exclude pneumonia and other infectious processes [1]. Conversely, the use of imaging procedures provides essential clues in making a presumptive diagnosis [1]. Recent reports have established that BAC (or all of its newly described variants) appears as a solitary nodule ranging from 5-30 mm in diameter, although lobar, multilobar or even patchy infiltrates may be seen on plain radiography or computed tomography (CT), suggesting its multicentric development in some patients [1] [3] [5] [6]. CT is often preferred to chest X-rays, as it provides a better view of the lung parenchyma, but a biopsy of the lesion is often necessary, especially when inconclusive findings are seen on CT [5]. Thus, the diagnosis of BAC (now called AIS or MIA) now rests on radiographic criteria, but more importantly, on a proper histopathological examination [5] [6].

• Bilateral Pulmonary Opacities

  In 7 patients the chest radiography revealed multiple bilateral pulmonary opacities, with air bronchogram and tendency to necrosis at 1. One patient had 2 pulmonary nodules. [erj.ersjournals.com]

• Bilateral Pulmonary Infiltrates

  A 52-year-old woman with human immunodeficiency virus (HIV) developed weight loss, cough, and breathing difficulties, accompanied by extensive bilateral pulmonary infiltrates. [ncbi.nlm.nih.gov]

• Pulmonary Infiltrate

  A 52-year-old woman with human immunodeficiency virus (HIV) developed weight loss, cough, and breathing difficulties, accompanied by extensive bilateral pulmonary infiltrates. [ncbi.nlm.nih.gov]

• X-Ray Abnormal

  Case report This was a case report of a 53-year-old woman who admitted in Al-Zahra Hospital due to chest X-ray abnormality founded during evaluation of weight loss and headache [Figure 1]. There was no history of dyspnea, chills or fever. [advbiores.net]

• Chest X-Ray Abnormal

  Case report This was a case report of a 53-year-old woman who admitted in Al-Zahra Hospital due to chest X-ray abnormality founded during evaluation of weight loss and headache [Figure 1]. There was no history of dyspnea, chills or fever. [advbiores.net]

• Anisocytosis

  Positive likelihood ratios allowed for identification of the 5 most useful pathologic features for the diagnosis of AC: multiple growth patterns, anisocytosis, atypia more than 75%, macronucleoli, and atypical mitoses. [ncbi.nlm.nih.gov]

• Pleural Effusion

  PATIENTS AND METHODS: Patients with histologically confirmed stage IIIB (with malignant pleural effusion) or stage IV adenocarcinoma with BAC features or pure BAC were eligible. [ncbi.nlm.nih.gov]

  No pleural effusions or evidence of mediastinal adenopathy. Sputum, right and left main bronchus lavage were positive for malignant cells consistent with carcinoma. [radiopaedia.org]

  Prevalence and incidence of benign asbestos pleural effusion in a working population. JAMA 1982;247:617-622. ‎ [books.google.it]

  effusion OR pleural tumor foci that are separate from direct pleural invasion by the primary tumor], any N, M0) Stage IV disease (any T, any N, M1 [distant metastases present]) Recurrent disease in a separate lobe after prior resection within the past [clinicaltrials.gov]

  Secondary findings of BAC were hilar and mediastinal lymphadenopathy, pleural effusion, atelectasis and pneumothorax. Hilar and mediastinal lymphadenopathy appeared frequently(43.3%). 7. [ir.ymlib.yonsei.ac.kr]

1. Thompson WH. Bronchioloalveolar carcinoma masquerading as pneumonia. Respir Care. 2004 Nov;49(11):1349-53.
2. Garfield DH, Cadranel JL, Wislez M, Franklin WA, Hirsch FR. The bronchioloalveolar carcinoma and peripheral adenocarcinoma spectrum of diseases. J Thorac Oncol. 2006;1(4):344-359.
3. Gardiner N, Jogai S, Wallis A. The revised lung adenocarcinoma classification—an imaging guide. J Thorac Dis. 2014;6(Suppl 5):S537-S546.
4. Yatabe Y, Borczuk AC, Powell CA. Do all lung adenocarcinomas follow a stepwise progression? Lung cancer. 2011;74(1):7-11.
5. Tang ER, Schreiner AM, Pua BB. Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS). J Thorac Dis. 2014;6(5):S489-S501.
6. Sardenberg RAS, Mello ES, Younes RN. The lung adenocarcinoma guidelines: what to be considered by surgeons. J Thorac Dis. 2014;6(5):S561-S567.
7. Jiang L, Yin W, Peng G, et al. Prognosis and status of lymph node involvement in patients with adenocarcinoma in situ and minimally invasive adenocarcinoma—a systematic literature review and pooled-data analysis. J Thorac Dis. 2015;7(11):2003-2009.