Pulmonary malignant lymphoma requiring surgical lung biopsy for diagnosis following coronavirus disease 2019 infection: a case report.

Background: Pulmonary involvement by peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), is an exceedingly rare extranodal manifestation with nonspecific radiological and clinical features. Its computed tomography (CT) findings-including ground-glass and consolidative opacities and, in some areas, a crazy-paving appearance-overlap with those of resolving infectious pneumonia and drug-induced lung injury, so that pulmonary lymphoma is readily mistaken for these more common conditions and the diagnosis is often delayed. Case Description: A 62-year-old man with a smoking history and stage IIIA classical Hodgkin lymphoma (cHL) treated six years earlier with bleomycin-containing chemotherapy-complicated by resolved grade 1 bleomycin-induced interstitial pneumonia-presented with productive cough and low-grade fever after a mild coronavirus disease 2019 (COVID-19) infection. Chest CT showed diffuse bilateral ground-glass opacities, with areas of a crazy-paving appearance, together with mediastinal and right hilar lymphadenopathy; the soluble interleukin-2 receptor (sIL-2R) level was markedly elevated (1,540 U/mL). Bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB) was non-diagnostic, and the patient deteriorated despite broad-spectrum antimicrobial therapy. Video-assisted thoracoscopic surgery (VATS) with wedge resection established the diagnosis of PTCL-NOS, and bone marrow biopsy showed no marrow involvement. Multiple lines of salvage chemotherapy failed to control the disease, and the patient died three months after diagnosis. Conclusions: This case underscores the essential diagnostic role of VATS lung biopsy when bronchoscopic investigation fails in patients with treatment-refractory pulmonary infiltrates. The co-occurrence of prior bleomycin exposure and post-COVID-19 pneumonia created overlapping radiological features that delayed diagnosis. PTCL-NOS should be considered in the differential diagnosis of treatment-refractory pulmonary infiltrates-even when nonspecific patterns such as crazy-paving are present-particularly in patients with a prior history of hematologic malignancy and markedly elevated sIL-2R. The temporal onset of disease following COVID-19 infection in this immunologically predisposed patient further raises awareness of a potential association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and lymphomagenesis.