Lung Biopsy inPneumocystis cariniiPneumonia: A Histopathologic Study of Typical and Atypical Features

Abstract

This study of 36 patients with Pneumocystis carinii pneumonia emphasizes a spectrum of histopathologic changes that have not been classically considered features of the infection. These atypical microscopic findings were present in 69% of the cases as defined in this retrospective examination. As expected, the suggestion of the correct diagnosis of Pneumocystis carinii pneumonia on the basis of a frozen section and without the aid of appropriate special stains was extremely difficult in the majority of biopsies. It is important for the pathologist to maintain the possibility of this infection in his differential diagnosis when he examines a pulmonary biopsy from a patient who is immunologically compromised.

Lung and chest wall mechanics in patients with acquired immunodeficiency syndrome and severe Pneumocystis carinii pneumonia

“…On the other hand, it is conceivable that, owing to the peculiar pathogenetic pathways of AIDS-related PCP, inflection points never occur in the static inflation V-P curve of these patients. In fact, the pathological findings of PCP in AIDS patients include interstitial infiltrates associated with alveolar occupation by eosinophilic exudates, hyaline membranes, macrophages, and cellular debris, which oppose recruitment, whilst oedema is moderate or absent [8,9]. Moreover, computed tomography scan performed in eight of our patients exhibited homogeneous diffuse interstitial and alveolar infiltration, at variance with what appears to be the most common finding in ARDS patients in whom dense opacities are mainly confined to the dependent lung regions [27].…”

“…On this basis it can be concluded that: 1) in five patients the aerated lung units retained nearly normal elastic properties, while in the other seven patients they became stiffer; and 2) airway resistance remained essentially normal in nine patients, increased in two patients, and probably decreased in one patient. Higher than expected values of Est,L could reflect fibrosis [6][7][8][9][10] and/or altered surfactant [33], while the contrasting changes in Rint,L could reflect the interaction of multiple factors (increased lung recoil, release of bronchoconstrictor or bronchodilating agents, intraluminal secretions, peribronchial oedema or infiltrates). That multiple factors with opposite effects were modulating the airway resistance of our patients, besides a reduction in ventilated lung units, is also suggested by the absence of a significant correlation between Est,L and Rint,L ( fig.…”

“…On the other hand, PCP has a distinctive histopathology: the alveoli are filled with few inflammatory cells and an acellular, eosinophilic, proteinaceous material that contains cysts and trophozoites of the organism, whilst the interstitial spaces contain predominantly mononuclear inflammatory cells [8,9]. Presence of fibrosis has also been observed, particularly in severe pneumocystosis [10].…”

The Pitfall in Evaluating Several Serological Markers of Pneumocystis carinii Pneumonia in a Neutropenic Patient.

“…Pneumocystis carinii (P. carinii) is associated with histologic findings of interstitial pneumonitis and sometimes irreversible fibrotic changes (2). It has been reported that the severity of HIV-associated PCPis related to the percentage of neutrophilic granulocytes in the bronchoalveolar lavage (BAL) fluid at the time of diagnosis (3,4).…”

KL-6 as a Serologic Indicator of Pneumocystis carinii Pneumonia in Immunocompromised Hosts.

“…Pulmonary infection with P. carinii is associated with histologic findings of interstitial pneumonitis and irreversible fibrotic changes (3,4). KL-6, a human MUCImucin (5-7), has been reported to be a sensitive serum markerfor interstitial pneumonitis (8)(9)(10)(11)(12)(13)(14)(15).…”