Interstitial lung diseases (ILDs) encompass a diverse group of conditions characterized by inflammation and fibrosis of the lung tissue, which can lead to impaired lungs function and respiratory failure. Pulmonary arterial hypertension (PAH) and cor pulmonale are common complications of ILDs, resulting from increased resistance in pulmonary circulation and right heart strain. ILDs and PAH and cor pulmonale are often difficult to diagnoses as the symptoms can be non-specific and overlap with other respiratory diseases. Diagnostic tool such as pulmonary function tests, imaging studies and right heart catheterization are used to establish a definitive diagnosis and assess to disease severity. This case study summarizes the patient case of ILDs with PAH and cor pulmonale, including the underlying pathophysiology, diagnostic tool and management strategies. Additionally, we discuss the challenges in diagnosing and managing ILDs with PAH and cor pulmonale, as well as potential future direction in research and treatment.