Barking up the wrong tree: Vascular tree-in-bud due to intravascular lymphoma

A 59-year-old previously healthy woman presented with a six-month history of fever, nonproductive cough, and weight loss. The cause of these symptoms remained obscure despite a thorough, month-long hospitalization. On presentation, she was normotensive with a pulse of 98 beats/minute, respiratory rate of 20 breaths/minute, and a temperature of 39.4C. She was emaciated. Physical examination was notable for faint bibasilar crackles on lung auscultation. Initial laboratory testing revealed pancytopenia. Peripheral smear demonstrated normocytic, normochromic anemia without immature cells or schistocytes. Other notable laboratory findings included elevated levels of lactate dehydrogenase, elevated ferritin, and elevated levels of fasting serum triglycerides. A comprehensive laboratory evaluation for connective tissue disease was negative. Plain chest radiography was normal while computed tomography (CT) of the chest demonstrated sub-centimeter nodules in a branching centrilobular pattern as well as in a peri-lymphatic distribution without associated lymphadenopathy or organomegaly. The above constellation of laboratory abnormalities raised concern for hemophagocytic lymphohistiocytosis (HLH). Soluble IL-2 (CD25) receptor levels were markedly elevated. Bronchoscopy with transbronchial biopsies of the right lower lobe was performed, revealing intravascular lymphoma associated with HLH. Our case emphasizes the need for clinicians to consider vascular causes of tree - in-bud nodules in addition to the conventional bronchiolar causes. The case also is a reminder of the need to conduct an exhaustive search for malignancy, in patients with HLH.