A case ofangiotropic large cell lymphoma is reported in which the patient presented with only pulmonary symptoms. It suggests that this rare and highly malignant lymphoma should be considered in the differential diagnosis of interstitial lung disease, and shows the value of open lung biopsy in unexplained interstitial lung disease. This patient responded well to treatment with cyclophosphamide, doxorubicin, vincristine, and prednisone.Angiotropic large cell lymphoma is a rare disease characterised histologically by proliferating mononuclear cells within the lumen of capillaries, venules, arterioles, and small arteries.' Originally described in cutaneous small vessels,4 later reports have shown that various organs may be affected, especially the nervous system and adrenal glands.5Previously angiotropic large cell lymphoma was known as "malignant angioendotheliomatosis" presuming an endothelial origin of the tumour cells; but recent studies using cell surface markers suggest a lymphoid origin,236 and the terms angiotropic large cell lymphoma3 and malignant intravascular immunoblastic lymphoma7 have been suggested. We report a case presenting with pulmonary symptoms. Case reportA 56 year old woman, an insulin dependent diabetic, was admitted to hospital because of persistent fever over the preceding week, progressive exertional dyspnoea, a nonproductive cough, and malaise. Two years earlier she had had pancreatitis during a period of alcohol abuse, but she had since abstained from alcohol. Until the onset of fever she had been well. There were no complaints of weight loss, skin lesions, disorientation, arthralgia, pruritis, or nocturnal sweats. Ske kept a parakeet and a cat and had no known allergies. Her only treatment was insulin.Physical examination showed that she had a fever of 39°C and bilateral fine inspiratory rales at the bases of both lungs. No lymphadenopathy or hepatosplenomegaly was detected.The erythrocyte sedimentation rate was 45 mm in the first hour and the white blood cell count 4-8 x 109/1, with 57% segmented neutrophils, 17% band neutrophils, 18% lymphocytes, 3% monocytes, 1% myelocytes, 2% eosinophils, and 1% basophils. Arterial blood gas analysis showed the