Herpes simplex virus pneumonia: high-resolution CT findings

Abstract

The purpose of this study was to evaluate the high-resolution computed tomographic (HRCT) findings of five adult patients (either immunocompromised or immunocompetent) with herpes simplex virus (HSV) pneumonia. We retrospectively assessed HRCT images of 5 patients (all male patients, age range 39-70 years; mean 62 years) with HSV pneumonia. The specific pathological findings that allowed for a definite diagnosis of HSV pneumonia included the presence of intranuclear inclusion bodies on haematoxylin and eosin staining, or positive immunohistochemical staining. High-resolution CT scans (HiSpeed Advantage or LightSpeed QX/i, GE Healthcare) using 1- or 1.25-mm collimation at 10-mm intervals without intravenous contrast medium injection were assessed, in particular for the presence and distribution of parenchymal abnormalities including ground-glass attenuation, airspace consolidation, nodules and interlobular septal thickening. In two patients, pathological specimens were obtained from open lung biopsy or bronchoscopic biopsy, and were correlated with HRCT findings. Three HRCT patterns of pulmonary abnormalities were identified in our series of HSV pneumonia: predominant areas of diffuse or multifocal ground-glass attenuation, predominant areas of multifocal peribronchial consolidations, and a mixed pattern of both. Histopathologically, areas of ground-glass attenuation seen on HRCT corresponded to diffuse alveolar damage in one patient who underwent open lung biopsy. No specific differences in HRCT findings were seen between the immunocompromised and the immunocompetent patients. In patients suspected of having an acute lower respiratory infection, whether immunocompromised or immunocompetent, a possibility of HSV pneumonia can be included in differential diagnoses when diffuse or multifocal areas of ground-glass attenuation and/or consolidations are seen on HRCT.

Figure 1

A 39-year-old immunocompromised man with myelodysplastic syndrome who developed herpes simplex virus pneumonia 15 months after allogeneic bone marrow transplantation. (a) High-resolution (1.0-mm collimation) CT scans obtained at levels of the aortic arch shows predominant areas of diffuse ground-glass attenuation in both lungs. Note associated interlobular septal thickening (arrowheads). (b) Photomicrograph of pathological specimen obtained by open lung biopsy shows interstitial fibroblastic proliferation and hyaline membrane formation (arrowheads), suggesting a late exudative or proliferative phase of diffuse alveolar damage (haematoxylin and eosin, ×200). (c) Higher magnification photomicrograph of pathological specimen demonstrates alveolar lining cells containing an intranuclear inclusion (arrows), consistent with herpes viral infection (haematoxylin and eosin, ×400).

Figure 2

A 67-year-old immunocompetent man with herpes simplex virus pneumonia. High-resolution (1.0-mm collimation) CT scans obtained at levels of great vessels shows predominant areas of diffuse ground-glass attenuation. Note an area of lobular consolidation (arrows) and interlobular septal thickening (arrowheads). Centrilobular emphysema is seen in the underlying lungs.

Figure 3

A 67-year-old immunocompetent man with herpes simplex virus pneumonia. Conventional (5.0-mm collimation) and high-resolution (1.0-mm collimation) CT scans obtained at levels of the bronchus intermedius shows a pattern of multifocal peribronchial consolidations surrounded by small areas of ground-glass attenuation in both lungs. Air bronchograms are seen within the consolidations.

Figure 4

A 65-year-old immunocompromised man on steroid therapy for idiopathic pulmonary fibrosis who developed herpes simplex virus pneumonia. (a) High-resolution (1.0-mm collimation) CT scan obtained at the level of the inferior pulmonary vein shows a mixed pattern of diffuse ground-glass attenuation and subsegmental/segmental peribronchial consolidations (arrows). Motion artefact is seen because the patient was dyspnoeic and mechanically ventilated during CT scanning. (b) Photomicrograph of sputum smear cytological specimen demonstrates mononuclear and multinuclear epithelial cells with intranuclear inclusions, consistent with herpes viral infection (haematoxylin and eosin, ×400).