Therapy: The mass was removed by a wire snare, and four lymph nodes were excised by mediastinoscopy. Post-operatively, antibiotics were given to treat the pneumonia, and he was discharged 4 days later.

Gross and histologic changes: The specimen was a rounded, smooth-surfaced fragment of soft tissue, 1 cm in diameter. None of the lymph nodes contained tumor.

A. An overall view shows a circumscribed, non-encapsulated mass of mature adipose tissue traversed by small vessels. It is covered by normal respiratory epithelium, which is separated from the fat by a loose fibrous stroma that contains a large number of lymphocytes and plasma cells. The hemoptysis that can occur with these lesions is caused by the pneumonia secondary to the tumor and not by the tumor itself.

B. At higher magnification, the subepithelial fibrous tissue is chronically inflamed. The irregular dark blue area is a lymphoid aggregate. The underlying fat and blood vessels blend in with the fibrous tissue rather than being sharply demarcated.

C. The subepithelial tissue has chronic inflammatory cells (lymphocytes (without visible cytoplasm) and plasma cells (with visible cytoplasm)).

D. At the edge of the lesion, loose connective tissue and fat are mixed together.

What is the diagnosis? Answer

Clinical summary Discussion

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