The Shrunken Right Middle Lobe

With Reference to the So-called "Middle Lobe Syndrome"

Of all the lobes, the right middle is most subject to collapse. This is due to the fact that the middle lobe bronchus is especially vulnerable to compression and invasion by bronchopulmonary lymph nodes, the latter draining the lower as well as the middle lobe. An analysis of 16 cases of shrunken middle lobes reveals the cause to lie in cicatrizing tuberculous lymph nodes constricting the middle lobe bronchus. In some, the shrunken lobe is the seat of bronchiectasis; in others, there is tuberculous involvement of the bronchus and lobe. The significance of the existence of dormant caseocalcareous bronchopulmonary lymph nodes in the pathogenesis of several tuberculous and nontuberculous conditions is discussed.

The symptoms referable to shrunken middle lobes are of a bronchitic nature punctuated by acute seizures due to intercurrent pulmonary infections or hemoptysis. The relatively mild course of the disease, in most instances, accounts for the fact that the condition is often encountered in office practice. It is usually overlooked or erroneously ascribed to pleuropericardial adhesions or interlobar pleurisy. The diagnosis can be made by roentgenography in the postero-anterior, right lateral and lordotic projections. The shrunken lobe appears as a triangular or roughly quadrilateral density at the root of the lung. Tomography is helpful. Bronchoscopy is essential in determining whether or not one is dealing with bronchiogenic neoplasm. Bronchography is necessary to establish the presence of bronchiectasis. Definitive treatment consists of excision of the involved lobe unless the age and condition of the patient contraindicate surgery.