Intravascular Lymphoma Diagnosed by "Hot Lung" Sign.

A 73-year-old man visited us with a complaint of weight loss without other symptoms. Chest computed tomography (CT) showed slight reticular shadows on both lungs (Picture 1A, B) with an increased maximum standardized uptake value of 3.3 on positron emission tomography (PET)-magnetic resonance imaging (MRI), which is known as the hot lung sign (1) (Picture 1C). A blood examination showed elevated soluble interleukin-2 receptors (8,622 U/mL) without findings of lymphoma on whole-body CT, a bone marrow biopsy, spinal MRI, and a random skin biopsy. A transbronchial cryobiopsy performed under fluoroscopic guidance (Picture 1D) revealed atypical lymphocytes (Picture 2A, B) positive for CD20 (Picture 2C) and CD79a (Picture 2D) filling the vessels. The patient was diagnosed with intravascular large B-cell lymphoma (IVLBCL), which is challenging to diagnose and often requires surgery or an autopsy. “Hot lung” sign is defined as an increased diffuse uptake in both lungs, extending from the base of the lungs on PET, despite normal or slightly abnormal CT findings (1). A cryobiopsy was recently reported to provide sufficient specimens for a diagnosis of IVLBCL (2). Performing both PET and a cryobiopsy may enable the early diagnosis of pulmonary IVLBCL.

Picture 1.

Picture 2.

The authors state that they have no Conflict of Interest (COI).

Financial Support

This work was supported by JSPS KAKENHI Grant Number JP19K16966.