Biological Diagnosis of Granulomatous Pneumocystis Pneumonia

The intra-alveolar form of Pneumocystis jiroveci pneumonia (PjP) is a common pathology in immunocompromised patients, particularly those infected with HIV. The diagnosis is based on the detection of Pj in a LBA. Intra-tissue granulomatous form (PGP) is a rare entity observed in non-HIV immunocompromised patients. In this case, the LBA is mostly non-contributory and the diagnosis is based solely on the detection of cysts on histological examination on biopsy of a pulmonary nodule. For many years, it has been clearly demonstrated that the use of a specific PCR clearly improves the biological diagnosis of PcP. However, in case of granulomatous form this method is not implemented because the diagnostic hypothesis is not mentioned.

In 2018, two cases of PGP were diagnosed at 3-month intervals at Montpellier University Hospital Center. The diagnostic confirmation was obtained with PCR Pj. In this context the investigators will investigate the interest of implementing PCR Pj on biopsies on pulmonary nodules from hospitalized patients between 2015 and 2018. In all selected patients, histopathological aspect of the nodule was compatible with a PGP and, no other diagnosis has been confirmed (infectious, tumoral, inflammatory ...). Finally, 17 patients were selected to check retrospectively, if the presence of Pj could be at the origin of the pathology.