A 55-year-old woman with a 5-year history of Raynaud's phenomenon, 2 years of dysphagia after eating, generalized swelling sensation, thickened and hardened skin on both hands, and facial skin without wrinkles. Blood pressure (BP) 160/94 mmHg for the past week. Urinary protein ++ (1.5g/d), urine sediment red blood cells (RBCs) 10-15 per high power field (HPF). Blood urea nitrogen (BUN) 1 mmol/L, serum creatinine (Scr) 240 μmol/L. The clinical diagnosis is most likely systemic sclerosis. After confirmation, the characteristic pulmonary change in this case should be: