[Primary pulmonary lymphoma diagnosed by transbronchial biopsy and bronchoalveolar lavage findings]

A 45 year-old male was admitted to Tokyo University Hospital because of a submandibular tumor. Biopsy specimen of the tumor showed medium-sized non-Hodgkin's lymphoma of follicular type and immunoperoxidase staining of frozen sections demonstrated an overwhelming predominance of B lymphocytes with IgM, lambda chain. In the meanwhile, chest X-ray taken on admission showed an ill-defined consolidation with a tumor-like appearance in the right middle lung field. Transbronchial biopsy of this lesion revealed massive infiltrations of small and medium sized lymphocytes, having the same markers as those of submandibular tumor (IgM, lambda chain) and an analysis of bronchoalveolar lavage showed a significant increase of CD19-positive B lymphocytes. Reviewing of check-up X-ray films showed the lung lesion to have preceded the submandibular tumor and to have increased its size in several years. On the basis of the similarity of histological and immunohistochemical findings between pulmonary and submandibular tumor, and considering the time course of the appearance of these tumors, we concluded that these tumors were of the same histological nature and had originated in the lung and metastasized to submandibular gland. This is a relatively rare case of pulmonary lymphoma metastasizing to the submandibular gland, in which transbronchial biopsy specimen and analysis of lymphocytes in bronchoalveolar lavage were helpful in establishing the diagnosis.