Pneumocystis Pneumonia misdiagnosed as Pulmonary Tuberculosis in a patient with repeatedly false-negative HIV tests

Pneumocystis jirovecii pneumonia, previously known as Pneumocystis carinii Pneumonia (PCP), is a fungal infection most commonly encountered in immunocompromised patients and, in some cases, can be life-threatening. Patients at risk include those with cancer, HIV positive, transplant recipients, and those under immunosuppressive therapies. There are no specific signs or symptoms for PCP and its differential diagnosis includes other viral or bacterial pneumonias and also Tuberculosis, the latter especially in high endemic areas. We present the case of a 32 year-old female patient who presented to the hospital for dyspnea and cough, treated for Pulmonary Tuberculosis, and eventually diagnosed with Pneumocystis Pneumonia, in spite of her multiple false-negative HIV tests.