Adenomas

• Low grade malignancies –about 10% metastasize

• Most patients are under 50

            • Most common 1° lung tumor under age 16

            • Male to female ratio of 1:1

            • White to Black ratio of 25:1

• Pathologically, they fall into two groups:

            • Carcinoid—85%-95% of all adenomas

               • Kulchitsky cells=argentaffine cells

             • Part of APUD system (amine precursor uptake and decarboxylation)

           • Neurosecretory production of serotonin, ACTH and bradykinin

Salivary gland types

                 • Cylindromas—twice as common as mucoepidermoids

                     • Resembles salivary gland tumor

                     • More malignant potential than carcinoid (25%)

                • Mucoepidermoid

                • Mixed

               (CAMP=incidence of bronchial adenomas, where:

                  C=carcinoid

                  A=adenoid cystic carcinoma=cylindroma

                  M=mucoepidermoid

                   P=pleiomorphic=mixed)

• About 80% are situated centrally

            • Peripheral adenomas show a predilection for the RUL,RML and lingula

            • Cylindromas are always central

Clinically

            • Hemoptysis (40-50%)

            • Atypical asthma

            • Persistent cough

            • Recurrent pneumonia

            • Asymptomatic (10%)

Imaging

            •Atelectasis 2∞ bronchial obstruction, or

            •Pneumonia—are most common

            •Rarely may have obstructive emphysema

            •May be seen as a discrete mass, either centrally —80%—(carcinoid or cylindroma) or peripherally —20%— (carcinoid or mucoepidermoid)

            •May get bony metastases —usually blastic

•Very few carcinoids of the lung give rise to the Carcinoid Syndrome and those that do always have widespread metastases to the liver

•May be associated with Cushing’s Disease

•Overall prognosis: 75% fifteen-year survival

Think of bronchial adenoma when you see a smooth, well-marginated mass around the carina in a younger woman (DDX bronchial cyst—get CT)