benign metastasis

benign metastasis

A popular term for the presence of nonmalignant nonlymphoid tissue in lymph nodes which can lead to falsely describing, especially if found during a frozen section, the extraneous tissue malignant.
 
Examples
Salivary duct, thyroid follicles, müllerian epithelium, decidua endometriosis, nevus cells, colonic glands, breast tissue, megakaryocytes, adipose tissue, ectopic thymus, hyaline and proteinaceous material. (Technically these benign tissues are not metastatic, as metastasis is a multistep malignant process.)

benign 'metastasis'

A popular term for the presence of nonmalignant nonlymphoid tissue in lymph nodes–eg, thyroid follicles in cervical lymph nodes, which may be confused with carcinoma. See Lymph node inclusions.