A Pneumocystis jiroveci infection-associated mass clinically mimicking a malignancy (ie, pseudotumor) is rare and usually occurs in the lung in association with Pneumocystis pneumonia. Pneumocystis jiroveci pseudotumors of the small intestine are extremely rare and represent an unusual form of disseminated P jiroveci infection. We present a case of small-intestine P jiroveci pseudotumor as an acquired immunodeficiency syndrome-presenting illness in a patient with coinfection with cytomegalovirus, no pulmonary symptoms, and no known risk factors for human immunodeficiency virus infection. This case reinforces the potential importance of cytomegalovirus coinfection in the disseminated form of Pneumocystis infection and illustrates the importance of an expanded differential diagnosis when confronted with a clinically atypical mass lesion.