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

Abstract

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.

Figure 1

Radiological findings. A chest X-ray on admission, showing fine and diffuse nodular shadows in both lung fields (A). An initial CT scan of the chest demonstrated randomly-distributed micronodules and patchy ground-glass opacities (B).

Figure 2

A lung biopsy specimen of the left lower lobe, showing mild and homogeneous interstitial pneumonia, with the presence of numerous lymphoid follicles and no definite nuclear atypicality in the lymphocytes [hematoxylin-eosin stain; magnification ×40 (A), ×100 (insert upper), ×400 (insert lower): the boundary part between the lymphoid follicle (lower right) and surrounding tissue]. The immunohistochemical staining for L26, showing exclusively B-lymphocytes within the lymphoid follicles that exhibited a brownish reaction product [magnification ×40 (B), ×100 (insert)]. The immunohistochemical staining for bcl-2, showing the distribution of bcl-2 positive lymphocytes around the centers of lymphoid follicles (reactive hyperplasia pattern) [magnification ×40 (C), ×100 (insert)]. The immunohistochemical staining for UCHL-1, showing diffusely distributed T-lymphocytes in the alveolar walls or around the lymphoid follicles [magnification ×40 (D), ×100 (insert)].