Differential Diagnosis for Lung Mass with Fatigue and Shortness of Breath

Given the patient's presentation of a peripheral mass with poorly defined borders in the right upper lung field, along with symptoms of fatigue and mild shortness of breath without a history of smoking or lung disease, the following differential diagnoses can be considered:

• Single Most Likely Diagnosis

  • Adenocarcinoma: This is the most common type of lung cancer, especially in non-smokers. It often presents as a peripheral lung mass and can cause symptoms like fatigue and shortness of breath due to its potential to metastasize or cause local effects.

• Other Likely Diagnoses

  • Squamous Cell Carcinoma: Although less common in non-smokers, it's still a possibility, especially if there are other risk factors not mentioned.
  • Large Cell Carcinoma: A less differentiated form of non-small cell lung cancer, which can present similarly to adenocarcinoma.
  • Lymphoma: Both Hodgkin and non-Hodgkin lymphoma can present with lung masses and systemic symptoms like fatigue.

• Do Not Miss Diagnoses

  • Metastatic Disease: Given the patient's lack of smoking history, the possibility of a metastasis from another primary cancer (e.g., breast, colon, or melanoma) should be considered, as these can present with similar symptoms and radiographic findings.
  • Infectious Processes: Such as tuberculosis or fungal infections, which can cause lung masses and systemic symptoms, especially in immunocompromised patients.
  • Sarcoidosis: Although less likely to cause a single mass, it can present with lung nodules and systemic symptoms like fatigue.

• Rare Diagnoses

  • Carcinoid Tumors: These are slow-growing tumors that can present as lung masses but are less common and often have a better prognosis.
  • Hamartomas: Benign lung tumors that are usually incidental findings but can occasionally cause symptoms if large enough.
  • Pulmonary Langerhans Cell Histiocytosis: A rare condition that can cause lung nodules and cysts, more commonly seen in smokers but can occur in non-smokers as well.