Despite the fact that the term 'bronchial adenoma' suggests a non-neoplastic disease, it really stands for a multitude of tumor types, originating from the bronchial glands or epithelium, like carcinoid, adenoid cystic carcinoma, mucoepidermoid carcinoma or mucous gland adenoma. These neoplasms have a more or less prominent malignant potential that dictates clinical evolution.
Bronchial adenoma may be asymptomatic, especially if located in a distal area. In these cases, they are discovered incidentally. When the disease does induce clinical manifestations, these may mimic other conditions, like asthma or pneumonia. Symptoms like a cough (dry or productive), dyspnea, stridor or wheezing are caused by the existence of a bronchial obstruction, while hemoptysis is due to the rupture of the tumor vessels. Carcinoid syndrome is less frequently encountered   and more difficult to clinically diagnose , but it occurs in most patients that have liver metastases. Symptoms consist of asthma-like symptoms, flushing, palpitations and diarrhea. Furthermore, a recurrent infectious episode may complicate disease evolution and recognition.
When the tumor is big enough to compress neighboring structures, it may induce hoarseness, chest pain or chylothorax. Large tumors are more often found in the right lung rather than the left. The patient may complain of paraplegia, vertebral pain or sensory deficit due to acute spinal cord compression. Upper limbs may be painful and occasionally present with muscular atrophy. Horner syndrome (miosis, hemifacial anhidrosis, and partial ptosis) is caused by Pancoast tumors. Sometimes, the physician encounters a superior vena cava syndrome, characterized by dilated upper extremities and jugular veins, facial edema, papilledema and mental changes. Patients may also exhibit low-grade fever and weight loss. Breath sounds may prove asymmetric on auscultation and this method sometimes reveals condensation (pneumonia or abscess) processes distal to the obstruction site. Auscultation is occasionally consistent with emphysema or pleural effusion . The tumor itself may cause increased work of breathing with intercostal retractions, dyspnea, orthopnea, and cyanosis.
Bronchial carcinoid has also been described in the pediatric population. This age group is often symptomatic and have recurrent pulmonary infectious episodes . If a cough or wheezing do not properly respond to standard therapy, bronchial adenoma or carcinoid suspicion should be rapidly raised and investigated .
Blood workup in bronchial adenoma should include a complete blood cell count that will help differentiate pneumonia from other types of pulmonary condensation. The presence of anemia suggests significant blood loss by hemoptysis. A patient with severe respiratory distress should undergo an arterial blood gas determination, that may reveal decreased oxygen and increased carbon dioxide concentrations. A sputum culture is only useful if a distal infectious process exists. More specific markers are synaptophysin, calcitonin, bombesin, serotonin, neuron-specific enolase, corticotropin and antidiuretic hormone, keeping in mind that all of these are also increased in small cell lung cancer. Immunohistochemistry identifies tumor secretory substances.
The presence of a tumor can be suspected on a plain thoracic radiograph, but its type cannot be specified . Supplementary views, like the oblique ones, are sometimes useful. This investigation highlights the presence of different aspects, such as pleural effusion (that masks everything beneath it), a nodule or mass, an atelectasis area due to bronchial obstruction or infiltrative process. Hilar lymphadenopathy may signify infection or tumor . A normal radiological aspect does not necessarily exclude the disease. Therefore, in selected cases, a computed tomography (CT) scan can provide further information regarding calcification, compression, and location, as well as bronchiectasis or peripheral atelectasis. Contrast enhancement is homogeneous in typical carcinoid and less prominent in atypical one. Osseous metaplasia can also be encountered. Two-thirds of patients, those with somatostatin-positive tumors can be identified using octreotide or 99m technetium depreotide single-photon emission CT scanning, which represents alternative diagnosis methods.