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

Abstract

Background: Granulomatous reaction to Pneumocystis jirovecii is a rare but well-known pathological finding encountered in the setting of immunosuppression, HIV infection being the most common cause. It can also potentially complicate the treatment of hematological malignancies, typically when drugs lowering the count and function of lymphocytes are used. Lung biopsy is considered the gold standard for the diagnosis of granulomatous P. jirovecii pneumonia, whereas the diffuse alveolar form is usually detected cytologically in bronchoalveolar lavage (BAL). Case: A female patient pursuing R-CHOP chemotherapy for the treatment of multiple hematological malignancies developed a rapidly progressing dyspnea. Chest CT scans revealed a worsening of a known infiltrative lung disease thought to be secondary to her chemotherapy. Alterations compatible with a drug-induced interstitial lung disease and well-formed focally necrotizing granulomas were observed on an open lung biopsy, but no microorganism was identified with special stains. Eventually, a granulomatous reaction to P. jirovecii was found in a BAL and allowed appropriate treatment with rapid improvement of the dyspnea. Conclusion: Because granulomas are tissue-bound structures, they are rarely described in BAL. This article describes the first reported cytological diagnosis of a granulomatous reaction to P. jirovecii and the potential diagnostic interest of such a peculiar finding.

Hypercalcemia is common during Pneumocystis pneumonia in kidney transplant recipients

“…However, PJP is not listed as a differential diagnosis for extraparathyroid hypercalcemia. There are few evidences of the presence of a granulomatous reaction directly linked to Pneumocystis jirovecii 16,21,22 . Thus, this would be of interest to demonstrate a pathophysiological link between PJP and the secretion of 1,25(OH)2D, by highlighting a potential metabolism of 25 hydroxyvitamin D in cultured pulmonary alveolar macrophages of PJP infected patients, as it has been made for sarcoidosis for example 31,32 .…”

“…Increased calcium serum levels could be secondary to an extra-renal production of 1α-hydroxylase. Indeed, some reports of Pneumocystis pneumonia revealed the presence of inflammatory granulomas rich in macrophages and monocytes, capable of vitamin D activation and thereby inducing hypercalcemia 21,22 . Interestingly, 17 of the 21 described cases occurred in KTR, possibly suggesting a susceptibility in these patients for developing PJP-related hypercalcemia.…”

PneumocystisPneumonia Presenting as an Enlarging Solitary Pulmonary Nodule

“…Diagnosis of conventional Pneumocystis pneumonia has traditionally involved bronchoalveolar lavage. However, a literature review suggests that bronchoscopy is considered to have a very low diagnostic yield, if any, to detect P. jirovecii granulomas [ 9 ]. Despite this reports of granulomatous PcP being diagnosed by PCR assay of bronchoscopically obtained BAL sediment have been stated [ 10 ].…”

“…Granulomatous PcP accounts for approximately 5% of all PcP cases in AIDS patients, but the incidence in non-HIV patients is unknown due to a paucity of data [ 5 ]. A literature search revealed 17 previous cases of granulomatous PcP in patients with hematologic neoplasms [ 1 , 6 – 9 ]. Of these 17 published cases, only two patients presented with a solitary pulmonary nodule and only two previous reports of granulomatous PcP have been published with large B-cell lymphoma [ 6 , 7 ].…”

“…Awareness of a solid pulmonary nodule and granulomatous reaction is important as a single nodule could be seen as lymphoma involvement of the lung. In addition, it is important to realize that the diagnostic modality of bronchoalveolar lavage, which is typically done when diffuse infiltrates are present, may be of low yield if the organisms have not infiltrated in the alveolar lumen [ 7 , 9 ]. Here we describe a case of diffuse large B-cell lymphoma complicated by granulomatous PcP presenting as an enlarging solitary pulmonary nodule.…”