Progressive massive fibrosis

Progressive Massive Fibrosis (PMF), characterized by the development of large conglomerate masses of dense fibrosis (usually in the upper lung zones), can complicate silicosis and coal worker's pneumoconiosis. Conglomerate masses may also occur in other pneumoconioses, such as talcosis, berylliosis (CBD), kaolin pneumoconiosis, and pneumoconiosis from carbon compounds, such as carbon black, graphite, and oil shale. Conglomerate masses can also develop in sarcoidosis, but usually near the hilae and with surrounding paracicatricial emphysema. Progressive Massive Fibrosis (PMF), characterized by the development of large conglomerate masses of dense fibrosis (usually in the upper lung zones), can complicate silicosis and coal worker's pneumoconiosis. Conglomerate masses may also occur in other pneumoconioses, such as talcosis, berylliosis (CBD), kaolin pneumoconiosis, and pneumoconiosis from carbon compounds, such as carbon black, graphite, and oil shale. Conglomerate masses can also develop in sarcoidosis, but usually near the hilae and with surrounding paracicatricial emphysema. The disease arises firstly through the deposition of silica or coal dust (or other dust) within the lung, and then through the body's immunological reactions to the dust. According to the International Labour Office (ILO), PMF requires the presence of large opacity exceeding 1 cm (by x-ray). By pathology standards, the lesion in histologic section must exceed 2 cm to meet the definition of PMF. In PMF, lesions most commonly occupy the upper lung zone, and are usually bilateral. The development of PMF is usually associated with a restrictive ventilatory defect on pulmonary function testing. PMF can be mistaken for bronchogenic carcinoma and vice versa. PMF lesions tend to grow very slowly, so any rapid changes in size, or development of cavitation, should prompt a search for either alternative cause or secondary disease.