A 35 yo woman develops progressive shortness of breath with…
A 35 yo woman develops progressive shortness of breath with cough, over a 3 month period. She works in a library. On physical examination she is noted to have lymphadenopathy of her axilla and neck, bilaterally. A radiographic imaging shows multiple interstitial nodules in all lung fields. A lung biopsy is performed and a high power microscopic image of one of the nodules is shown. Which of the following is the most likely diagnosis?