An atypical case of lymphoproliferative pulmonary involvement in a patient with Sjögren’s syndrome: a case report

BACKGROUND: Sjögren’s syndrome is characterized by lymphocytic infiltration of the exocrine glands, together with polyclonal B-cell activation, and lung diseases are well-known complications of the disease. Therefore, in most cases associated with Sjögren’s syndrome, infiltrating lymphocytes in the lung specimen exhibit the features of B-cells. We herein report an atypical case of lymphoproliferative pulmonary involvement in a patient with Sjögren’s syndrome. CASE PRESENTATION: A 46-year-old female was admitted to our hospital because of an abnormal chest roentgenogram finding on a medical checkup. Chest computed tomography showed randomly-distributed micronodules and patchy ground-glass opacities. A surgical biopsied specimen showed an atypical pattern of interstitial pneumonia with numerous lymphoid follicles. Among the infiltrating lymphocytes in the lung, only the monoclonality of the T-cells was proven by a gene rearrangement analysis, but there was no cytological atypicality or genetic disorder revealed by testing the bone marrow aspirate. A diagnosis of Sjögren’s syndrome was made based on the patient’s other symptoms and these negative findings. The patient’s pulmonary lesions have been successfully treated and remission has been maintained for over three years with corticosteroid treatment alone. CONCLUSION: The present patient was an atypical case of lymphoproliferative pulmonary involvement in a patient with Sjögren’s syndrome. Although monoclonality of the infiltrating T-cells was proven, the clinical course and the findings of the imaging and laboratory examinations were inconsistent with the previously-reported cases of primary pulmonary T-cell lymphoma. This suggests that the monoclonality of lymphocytes does not always define malignancy. The diagnosis of malignant lymphoma or lymphoproliferative diseases should be made clinically, pathologically and cytogenetically to rule out other similar diseases.