Pathomorphological Features of Pneumonia Caused by Pneumocystis Jirovecii in Patients with HIV Infection/AIDS

Objective — to determine the nature and severity of the pathomorphological features of pneumonia caused by Pneumocystis jirovecii in patients with (HIV) infection/acquired immunodeficiency syndrome (AIDS). Materials and methods. The pathomorphological study of autopsy material of 7 cases of HIV/AIDS was conducted on the basis of the Lviv Regional Pathological Bureau and the Department of Pathological Anatomy and Forensic Medicine of the Danylo Halytsky Lviv National Medical University. In all cases, HIV infection was diagnosed during life with serological verification. Opportunistic infections were diagnosed with suspected pneumonia caused by Pneumocystis jirovecii (P. jirovecii). Microscopic examination of the lungs was carried out with additional staining with azure-eosin and PAS-reaction. For lung damage, a semiquanti­tative assessment was used: 1+ for mild damage, 2+ for moderate damage, and 3+ for severe damage. Results and discussion. Morphological diagnosis of lung damage at the macroscopic level in the presence of pneumocystis pneumonia in cases of HIV/AIDS does not have absolutely specific symptoms, despite subtotal or total damage and the «rubbery» consistency of poorly aerated lung tissue. Histomorphologically, lung lesions caused by P. jirovecii were characterised by alveolar spaces filled with pink foamy amorphous material consisting of proliferating fungi and cellular debris. Comparative microscopic evaluation of histopathological lesions showed that in lungs with mild lesions, Pneumocystis was located in small amounts closer to the alveolar wall, whereas in lungs with moderate and severe damage, massive accumulation of these fungi was observed in the alveolar spaces. The affected lungs revealed interstitial inflammation with moderate lymphomacrophagic infiltration, the presence of a granulomatous reaction around clusters of P. jirovecii with the formation of small nodules and diffuse desquamation of alveolocytes, and, in the presence of aspergillus, the appearance of purulent-necrotic foci. Conclusions. Histological examination of lungs affected by P. jirovecii in patients with HIV infection/AIDS is obligatory for verify a reliable diagnosis and to determine the nature and severity of the pathomorphological features of pneumocystis pneumonia.