Atypical presentation of progressive disseminated histoplasmosis in a patient recently diagnosed with AIDS.

Opportunistic infections, including progressive disseminated histoplasmosis (PDH), may have variable and surprising presentations in patients with AIDS. This can be either a primary infection or reactivation of a latent infection. Latent infections may occur due to being unmasked by the immune reconstitution inflammatory syndrome after the initiation of combined antiretroviral therapy. PDH can be difficult to diagnose in patients with AIDS due to its variable presentation and many overlapping symptoms with other opportunistic infections. Serum and urine antigen testing are highly sensitive and typically used as the initial diagnostic test to workup suspected PDH. However, negative antigen and antibody tests do not rule out Histoplasmosis capsulatum infection and suspicion should remain high for PDH in the right clinical context. A definitive diagnosis may require biopsy-proven narrow-based budding yeast. We present an interesting patient with AIDS who presented with worsening cognitive decline and was ultimately diagnosed with PDH based on biopsy histopathology in the setting of negative antigen and antibody testing.