Transposition, apotheosis and benign metamorphosis-lymph node

The cells may be derived from the paramesonephric ducts, salivary gland tissue, breast tissue, thyroid follicles, squamous epithelium or mesothelial incorporation. Paramesonephric duct like configurations and inclusions are preferentially located in pelvic lymph nodes and may simulate the uterine tube epithelium. Breast tissue inclusions are chiefly constituted of ectopic mammary glands and ducts of diverse morphology and unknown aetiology. Thyroid inclusions may be incorporated in the cervical and axillary lymph nodes. Mesothelial inclusions appear particularly in the mediastinal lymph nodes of the patients with pleural and pericardial effusions. The occurrence of melanocytic cells discovered in the lymph nodes are attributed to the faulty migration of neural crest cells or they may arise as benign metastasis of existing dermal nevi. The diagnosis of benign inclusions is necessitated in order to exclude adenocarcinomatous lymph node transformation and metastasis in patients presenting with benign nodal proliferations. The existence of benign inclusions was initially recounted by Reis et al. in 1897.1 These are defined as tubular spaces corresponding to cysts, appearing in lymph nodes of patients who may undergo surgical interventions for malignant tumours of the uterus, cervix and vulva. Inclusions may as well arise in non malignant disease processes and may be situated in locales extraneous to the pelvic cavity such as in the lumbar, mediastinal, parotid, submandibular, jugular, hepatic and iliac lymph nodes. Brooks et al divided the inclusions in three sub-categories, epithelial, nevomelanocytic and decidual.2