Pulmonary T-cell lymphoma masquerading as eosinophilic pneumonitis.

Primary pulmonary T-cell lymphoma is an unusual subtype of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). This is a general term used to describe a diverse group of T-cell-type lymphomas that would otherwise not be classified as a PTCL. Among non-Hodgkin's lymphomas, PTCL accounts for 12% of cases. PTCL-NOS accounts for approximately 25% of all PTCL cases. Primary pulmonary T-cell lymphoma is associated with unfavorable outcomes and has a poor prognosis. Being a rare disease, epidemiological data regarding primary pulmonary T-cell lymphoma continues to be sparse at this time. We present a case of PTCL, which was misdiagnosed as eosinophilic pneumonitis (EP) based on samples obtained from transbronchial cryobiopsy. To our knowledge, this is the first reported case of PTCL masquerading as EP.