Differential Diagnosis in Patients Presenting With Peripheral Lymphadenopathy: Tuberculosis, Sarcoidosis, or Malignancy.

Differential diagnosis of peripheral lymphadenopathies is important in terms of not missing infections or non-infectious diseases and early diagnosis of malignancies. Preliminary diagnoses of tuberculosis, sarcoidosis, and malignancy were considered for two clinically similar patients, a 33-year-old man and a 41-year-old woman, who presented to our clinic with neck swelling. The male patient's exposure to tuberculosis and the chest x-ray brought us closer to the diagnosis of tuberculosis reactivation. The female patient's multiple peripheral lymphadenopathies and metastasis-suspicious lesions seen on positron emission tomography increased our suspicion of malignancy. However, in the final diagnostic process, the female patient was diagnosed with tuberculous lymphadenitis, and the male patient was diagnosed with sarcoidosis. We presented these two cases to show that it isn't always easy to distinguish tuberculosis and sarcoidosis with clinical, radiological, laboratory, and histopathological findings, and to draw attention to the importance of microbiological evaluation.