Peripheral T cell lymphoma initially presenting in lung biopsies: A diagnostic challenge

Primary or secondary pulmonary involvement by peripheral T cell lymphoma (PTCL) is rare and difficult to diagnose particularly via lung biopsies.

22 cases of PTCL diagnosed initially in lung biopsies between January 2006 and November 2020 were retrospectively reviewed followed at Nanjing Drum Tower Hospital and the First Affiliated Hospital of Zhengzhou University, respectively, including clinical manifestations, baseline biochemical indexes, images, histological findings and other available ancillary studies such as immunostaining, Epstein-Barr virus encoded RNA (EBER) in situ hybridization and T-cell receptor rearrangement analysis upon diagnosis.

The median age of these patients was 59 years old (range: 29-82 years) at diagnosis. The majority of them complained of fever, cough and fatigue. Computed tomography scans mainly revealed multiple ill-defined nodules/masses of various sizes and densities with or without air bronchogram. Microscopically, most lesions showed lymphoid cells with clear cytoplasm and irregular nuclear contours diffusely infiltrating alveolar septa or alveolar spaces in an inflammatory background. Several cases had a predominance of small neoplastic cells (n = 4) with atypical, irregular nuclei. One case showed a diffuse monotonous pattern of growth. Angioinvasion and necrosis were not uncommon findings. The neoplastic cells in all cases were positive for one or more T-cell markers, and negative for B-cell-lineage antigens and EBER. 19 out of 22 patients had complete follow-up information, and 17 patients were dead at the last follow-up.

Pulmonary involvement by PTCL is rare with dismal outcome. Aggressive clinical course and several clinicopathologic clues, albeit unspecific, may alert the pathologists of the possibilities of pulmonary PTCLs.