We present a case of a tumor in the oblique fissure of the right lung which presented histological characteristics that made difficult differentiation between thymoma and benign hyperplasia of a lymph node. Because ectopia of thymic tumors is rare, attention is called to the occurrence of lymph nodes which can lead to diagnostic confusion, a matter of importance, in view of the difference in prognosis.
If thymoma is defined as a tumor of the thymus gland composed always of lymphocytes and reticulum cells in varying proportion, it becomes an entity whose behavior is definite and predictable.2,13 One of its characteristics is spreading by direct invasion rather than by embolization via the blood and lymph streams, much in the manner of basal-cell carcinoma of the skin.10 Thus, when tissue resembling a thymoma is found in locations other than the anterior mediastimum its origin becomes a matter for speculation. While
JAMPLIS RW, NORTH FS, JOHNSON WD. Benign Interlobar Hyperplastic Lymph Node Resembling Thymoma. Arch Surg. 1961;83(6):894-897. doi:10.1001/archsurg.1961.01300180094018