Intravascular lymphomatosis of the T cell type presenting as interstitial lung disease--a case report.

Intravascular lymphomatosis (IL) is a rare and generally fatal disease characterized by proliferation of large lymphoma cells almost exclusively within the lumen of small blood vessels. The skin and central nervous systems are typically affected, but involvement of other organs, such as lung, has been described. Predominant lung involvement without cutaneous and neurologic manifestation is very rare and difficult to diagnose. Originally considered as an endothelial disorder, IL has recently been reclassified as lymphoma. Most of the cases reported are of B cell lineage with a few cases of T cell type. We describe a case of the T-cell type IL manifested clinically as an interstitial lung disease without involvement of skin and central nervous systems. Immunohistochemical studies showed the T-cell nature of the neoplastic cells in open lung biopsy sample.