Talk:Medical lung diseases

Follicular bronchiolitis

Microscopic description

A. The sections include two pieces of peripheral lung tissue. The principal abnormality is large aggregates of lymphoid tissue, with active germinal centers containing tingible-body macrophages, at all identified peribronchiolar regions. There are no granulomas.

The walls of the terminal airways have a normal thickeness. The airspaces have a moderate number of bland-appearing scattered pulmonary macrophages. There is no venous dilation and no septa thickening or edema.

The pulmonary vasculature is normal. There is no thickening of the small muscular arteries or intimal hyperplasia to suggest pulmonary hypertension.

Specials stains (Gram, ZN, PAS, PASD, GMS) are negative for micro-organisms. Immunohistochemical stains for Adenovirus, RSV, and CMV are all negative. Immunohistochemical stains for CD3, CD4, CD8 and CD20 show that the lymphocytes are predominantly B cells and that there are more CD4 T cells than CD8 T cells. Normal neuroepithelial bodies are identified with immunostains for chromogranin A, synaptic vesicle 2 and serotonin.

B, C. The sections show lymph nodes with a moth-like appearance, that have abundant histiocytes in the sinuses and secondary follicles. Specials stains (Gram, ZN, PAS, PASD, GMS) are negative for micro-organisms.

Final diagnosis

A. Lung, right lower lobe - apical segment, wedge biopsy - follicular bronchiolitis, see comment.

B. Lymph node, right superior mediastinal, biopsy - sinus histiocytosis.

C. Lymph node, right posterior mediastinal, biopsy - sinus histiocytosis.

Comment

There is no evidence of an infection; however, this cannot be completely excluded on a pathologic basis.