A Case of Peripheral T Cell Lymphoma Presenting as Severe Hypoxic Respiratory Failure ？？ A Case Report ？？ Joon Seok Choi, M.D.*, Hong-Joon Shin, M.D.*, Eun-Young Kim, M.D.*, In-Jae Oh, M.D.*, Kyu-Sik Kim, M.D.*, Yu-Il Kim, M.D.*, Sung-Chul Lim, M.D.*, Young-Chul Kim, M.D.*, Yoo-Duk Choi, M.D.†, Hyun Ju Seon, M.D.‡ and Yong Soo Kwon, M.D.* Departments of *Internal Medicine, †Pathology, ‡Radiology, Chonnam National University Medical School, Gwangju, Korea. We describe here the first known case in Korea of pulmonary involvement with peripheral T cell lymphoma and the patient presented with severe hypoxic respiratory failure. A 57-yr-old man was admitted to our hospital with rapid progression of dyspnea and bilateral diffuse infiltration on a chest radiograph. He received mechanical ventilation and low dose corticosteroid treatment under the suspicion of critical illness-related corticosteroid insufficiency. Transbronchial lung biopsy revealed large atypical lymphoid cells with positivity for CD3＋. We diagnosed this patient as having a peripheral T cell lymphoma and we treated him with high dose corticosteroid. His clinical and radiologic findings rapidly improved and then he received a full dose of chemotherapy for the peripheral T cell lymphoma.