Lung Cancer: Given the patient's age, smoking history, symptoms of blood-tinged sputum, unintentional weight loss, and a mass in the right supraclavicular region (suggestive of metastasis), lung cancer is the most likely diagnosis. The presence of a supraclavicular mass is particularly concerning for metastatic disease.

Tuberculosis (TB): Although less likely than lung cancer, TB can cause chronic cough, hemoptysis, weight loss, and lymphadenopathy. The patient's smoking history and age do not rule out TB, especially if she has been exposed or has a compromised immune system.
Chronic Obstructive Pulmonary Disease (COPD) with Possible Complication: COPD is common in smokers and can lead to chronic cough and weight loss. However, the presence of blood-tinged sputum and a supraclavicular mass suggests a complication such as lung cancer or a severe infection.
Pneumonia or Lung Abscess: These conditions can cause cough, hemoptysis, and weight loss, especially in smokers. However, they typically do not cause supraclavicular lymphadenopathy unless there is significant spread or an underlying condition predisposing to such spread.

Lymphoma: Although less common, lymphoma can present with lymphadenopathy, weight loss, and systemic symptoms. A supraclavicular mass could be a sign of lymphoma, and it's crucial not to miss this diagnosis due to its different treatment approach.
Metastatic Cancer from Another Primary Site: If the patient has a history of another cancer, the supraclavicular mass could represent metastasis from that primary site. This would significantly alter the treatment plan and prognosis.
Infectious Diseases (e.g., Histoplasmosis, Coccidioidomycosis): In endemic areas, these fungal infections can cause similar symptoms, including lymphadenopathy and pulmonary symptoms. Missing these diagnoses could lead to inappropriate treatment and poor outcomes.

Sarcoidosis: This autoimmune disease can cause lymphadenopathy, pulmonary symptoms, and weight loss. However, it is less likely given the patient's age and the specific combination of symptoms.
Castleman Disease: A rare lymphoproliferative disorder that can present with lymphadenopathy, systemic symptoms, and occasionally pulmonary symptoms. It is much less common and would be considered only after ruling out more likely diagnoses.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can cause pulmonary and systemic symptoms, including lymphadenopathy. It is less likely but should be considered in the differential diagnosis due to its potential for severe complications if untreated.