Hello Thank you for trusting HCM Apical pleural thickening refers to pleural thickening of the apical portion of the lungs. The apical portion, or apices, of the lung is the rounded top portion of the lung. When the pleural layers become hardened it becomes increasingly difficult to breathe due to restricting the lungs ability to expand during inhalation. Causes : bacterial pneumonia, chemotherapy, infection and lupus,asbestosis, tuberculosis etc. For you it is localised nothing to worry until unless it cause severe dyspnea, chest pain. But diffuse pleural thickening need surgical release of lungs. Please consult your doctor he will select suitable treatment to you.