Human T-cell leukemia virus type 1 (HTLV-1) carriers are rarely subject to inflammatory disorders in multiple organs, other than the well-known complication, adult T-cell leukemia/lymphoma (ATLL). HTLV-1 associated bronchiolo-alveolar disorder (HABA) has been proposed as an immune mediated pulmonary reaction seen rarely in HTLV-1 carriers. The reported clinico-pathological patterns of HABA are diffuse panbronchiolitis (DPB) and lymphoid interstitial pneumonia (LIP).
We here report three cases of HTLV-1 carriers showing miliary micro-nodules throughout both lungs. Microscopic examination in the video assisted thoracic surgery biopsies demonstrated that all cases had multiple discrete micro-nodules which consisted of marked lymphoid infiltration, granulomas, eosinophils and a few foci of necrosis inside the granuloma. No findings indicating ATLL, other neoplastic conditions, infection or interstitial pneumonia, including DPB and LIP, were present following panels of special staining and immunohistochemical examinations. Two patients improved without treatment within one month, with no evidence of recurrence after 7 years. One patient showed slow deterioration of lung reticular shadows in spite of a low dose corticosteroid therapy (prednisolone 10 mg/day). We believe these cases may be a newly recognized variant of HABA.