Nodular Lymphoid Hyperplasia as Incidental Finding of Suspect Pulmonary Mass

Abstract

Nodular lymphoid hyperplasia of the lung is a rare disease of polyclonal lymphoid proliferation. The incidental finding of a solid nodular lesion with irregular margins adjacent to the visceral pleura in the reported case was highly suggestive of malignancy. The present report underscores the typical immunohistochemical findings and the benign course of nodular lymphoid hyperplasia. The current knowledge about disease aetiology and the value of different diagnostic tools to distinguish nodular lymphoid hyperplasia from other pulmonary lymphoid lesions are summarized by a review of the literature. Surgical resection is not only diagnostic but also curative with no evidence so far that NLH can regress without operation. The present case shows the spontaneous regression of NLH after CT-guided biopsy indicating that an alternative, less invasive diagnostic approach has curative potential.

Figure 1

Chest computed tomography scans. (a) The initial scan shows a solid nodular lesion with irregular margins and adjacent to the visceral pleura in the right lower part of the upper lobe. (b) Five years later, the CT scan revealed only a small scar in the former lesion.

Figure 2

Histopathological appearances of the tumour. (a, b) Lymphoproliferative lesion was composed of dense infiltrates of mature lymphocytes and sporadic plasma cells along with lymphoid follicles with germinal centers. (a) Hematoxylin-eosin (H&E), ×10. (b) H&E, ×40. (c, d):Immunohistochemical (IHC) staining for immunoglobulin (Ig) ĸ (c) and Ig λ. (d) Light chains revealed polyclonal reactivity (×40). (e) IHC staining using CD20 antibodies showed high densities of B cells in reactive follicles. (f) Ki-67 IHC staining revealed high proliferative activity in the germinal center with no evidence of malignancy.