Human Immunodeficiency Virus (HIV)-related Opportunistic Infections (OI), including Pneumocystis jiroveci pneumonia (PCP), have become much less commonplace with anti-retroviral therapy (ART). Despite this, OIs are still common and it is important to remain vigilant for their presence and be aware of how ART and OI chemoprophylaxis may lead to atypical disease presentations. We present the case of a 51-year-old woman with HIV and CD4+ T helper lymphocytes cell count > 200 cells/ul on both ART and trimethoprim/sulfamethoxazole prophylaxis who presented with cavitating lung masses, mediastinal lymphadenopathy and pleural effusions. Negative bronchoalveolar lavage (BAL) and transbronchial biopsy (TBBx) prompted a second diagnostic procedure with a transthoracic core needle biopsy; the final diagnosis was granulomatous PCP. This case showcases a very rare presentation of PCP, with both large cavitating lung masses on imaging and granulomatous reaction on pathology, as well as the challenge of a potentially missed diagnosis with negative BAL and TBBx requiring transthoracic core needle biopsy for a final diagnosis.