A Severe COVID-19 Pneumonia Revealing a Lepidic Adenocarcinoma: A Diagnostic Challenge during the Pandemic Period.

A 46-year-old and active female smoker was admitted to our ICU for acute respiratory failure. Her past medical history was marked by an episode of community-acquired pneumonia 5 months before, with particularly frothy expectoration. The computed tomography scan had shown a left basal alveolar consolidation (Figure 1A). The frothy expectoration and the dyspnea persisted despite antibiotic therapy.

Figure 1.

(A) Computed tomography scan performed 5 months before ICU admission showing a left lower lobe consolidation (yellow arrow) with minimal peripheral ground-glass opacities (yellow dashed arrow); (B) computed tomography scan during ICU stay showing the extension of the left lower lobe consolidation (red arrow) and the appearance of bilateral ground-glass opacities (red dashed arrows).

On ICU admission, the patient required high-flow nasal oxygen therapy. Coronavirus disease (COVID-19) severe pneumonia was diagnosed by a positive nasopharyngeal PCR test. A new chest computed tomography scan showed the extension of the alveolar consolidation associated with bilateral ground-glass opacities (Figure 1B). In view of the atypical presentation with frothy sputum and the prolonged course of the pneumonia, a fiberoptic bronchoscopy was performed to look for another diagnosis. The BAL showed 360,000 cells/ml, of which more than 80% were carcinomatous cells suggestive of a lepidic adenocarcinoma (Figures 2A and 2B). Transbronchial biopsies confirmed the diagnosis of lepidic adenocarcinoma with the presence of adenocarcinomatous cells in collapsed alveoli (Figures 3A and 3B). Corticosteroid therapy was pursued for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia, in association with a chemotherapy combining carboplatin, pemetrexed, and bevacizumab. The patient was discharged from the ICU 7 days later.

Figure 2.

BAL showing a majority of carcinoma cells. (A) May Grünwald Giemsa–stained cells from BAL after cytocentrifugation (×10). (B) Enlargement of A (×40). M = macrophages; T = tumor cell clusters.

Figure 3.

Bronchial biopsy with nonmucinous adenocarcinomatous cells. (A) Hematoxylin and eosin safran staining (×20). (B) Expression of TTF1 (transcription termination factor 1) in the nuclei of the adenocarcinomatous cells exhibiting intense brown staining (×20). The asterisks indicate normal epithelial cells. G = bronchial glands; T = tumor cell.

Lepidic adenocarcinoma is a well-differentiated adenocarcinoma developed along intact alveolar septa without invasion of the stroma, pleura, or vessels (1). The clinical spectrum of symptoms is broad and may ultimately lead to acute respiratory failure (2, 3). Thoracic imaging may mimic an infectious etiology (3, 4), mainly ground-glass attenuation, which is also frequently found during the COVID-19 pandemic (5, 6). In this context, the diagnosis may be challenging and warrants cytologic respiratory samples in case of atypical presentation of “acute pneumonia.”