Granulomatous <i>Pneumocystis jiroveci </i>Pneumonia in a Patient with Diffuse Large B-Cell Lymphoma: Case Report and Review of the Literature

Abstract

Here we report a case of diffuse large B-cell lymphoma who developed granulomatous Pneumocystis jiroveci pneumonia (PJP) after rituximab and combination chemotherapy. The infection presented as a solitary pulmonary nodule (SPN) instead of the commonly seen diffuse ground-glass infiltrates. The diagnosis was made by wedge resection of the nodule. Both the CD4+ lymphocyte count and immunoglobulin level were low. A literature search revealed 14 granulomatous PJP patients with hematological neoplasms, including the present case, which was the first with diffuse large B-cell lymphoma and the only patient receiving rituximab before PJP development. In addition to our report, only one case had previously presented with an SPN. Our experience suggests that granulomatous PJP should be considered a possible etiology when immunocompromised patients develop fever and SPNs.

Single Nodular Opacity of GranulomatousPneumocystis JiroveciiPneumonia in an Asymptomatic Lymphoma Patient

“…Nodular opacities in Pneumocystis jirovecii ( P. jirovecii ) infection are related with granulomatous response to PJP infection on histopathologic examination that is an uncommon form of Pneumocystis infection. Solitary pulmonary nodule in patients with PJP infection is very rare and only 3 cases have been reported in the English literature (4, 5, 6). In addition, imaging findings of single nodular opacities in lymphoma patients can mimic lymphoma involvement of the lung or other infectious lesions.…”

Granulomatous Reaction to <b><i>Pneumocystis jirovecii</i></b> Diagnosed in a Bronchoalveolar Lavage: A Case Report

“…In order to mount an appropriate defense against P. jirovecii , both T and B lymphocytes are crucial to coordinate an inflammatory response, produce antibodies and eventually clear the microorganism [1,2,3,9]. Any defect in either the function or count of these cells can lead to P. jirovecii pneumonia.…”

“…A few articles document its occurrence during the treatment of hematological and solid malignancies, typically when anti-CD20 drugs (such as rituximab) and/or corticosteroids are used. These drugs lower the circulating lymphocyte count and interfere with their function, thus impeding the usual lymphocyte-dependent defense against P. jirovecii [1,2,3]. It is of note that rituximab and corticosteroids are also used for the treatment of various conditions such as pediatric nephrotic syndrome, transplantation, rheumatoid arthritis or Wegener's granulomatosis, and articles documenting either diffuse alveolar or granulomatous forms of P. jirovecii pneumonia arising in the course of the treatment of these conditions can be found in the literature [1,4,5,6].…”

“…A review of the available literature points out that bronchoscopy with cytological analysis is commonly considered to be of very low diagnostic yield, if any, to detect P. jirovecii granulomas, whereas lung biopsy, either open or transbronchial, is widely regarded as the gold standard [1,3,4,7,8]. From the cases described by Hartel et al [7], the false-negative rate that we can calculate is at best as high as 35% in open lung biopsies.…”

Chronic Pneumocystis jiroveci presenting as asymptomatic granulomatous pulmonary nodules in lymphoma

“…2 Including our case, it has been reported in only 15 cases of haematological malignancies to date. 3 Granuloma formation has been hypothesised to be determined by host factors, possibly due to a change in CD4þ lymphocyte numbers or function, however the actual mechanism has yet to be identified. 4 Granulomatous P. jiroveci is more frequently associated with atypical radiological manifestations, however even amongst these, solid nodules without evidence of accompanying infiltrates are rare.…”