Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.
Introduction: The lymphatic organs are subdivided in primary, secondary, and tertiary. The latter are scantly known structures, typically containing far fewer lymphocytes, imported from blood and lymph, which can be found theoretically in any abdominal or extraabdominal site. The present authors' intent was to search them in the mesentery and peritoneum of the female pelvis, in order to trace a possible line of evolution towards more mature lymphatic organs, and to evaluate their immune arrangement. Materials And Methods: The authors also investigated the normal mesentery and peritoneum, obtained from ten surgical specimens of hysterectomy with bilateral salpingo-oophorectomy, performed for symptomatic uterine prolapse, in patients aged between 60 and 70 years. After routine procedures of diagnosis and staging, the representative lymphatic tissue was submitted to immunohistochemical characterization for CD20, CD3, CD4, CD8, CD56, CD68, CD138, and podoplanin. Results: The authors were able to recognize in a simple aggregate of lymphocytes, gathered around a capillary or arteriola, the primordial nucleus of the tertiary lymphatic organ. Over time, this microaggregate increases in size and volume for the accumulation of lymphocytes, until it reaches the final conformation of a small lymph node, equipped with a thin capsule and a proper hilus. Its core is represented by CD20+ B lymphocytes, while CD3+ T lymphocytes are less numerous and almost exclusively represented by CD4+ T-helper lymphocytes, being the CD3+ T-cytotoxic reduced to a minimum percentage. At its periphery, some CD68+ histocytes can be also observed; no CD56+ NK lymphocytes, neither CD138+ plasma cells were detected. Moreover, the immunohistochemistry for D2-40 did not reveal significant neolymphangiogenesis. Conclusion: Tertiary lymphatic organs can be considered a reserve system, ready to replace the lymph nodes, when they become aged or inefficient, or when their increase in number is requested. Therefore, the tertiary lymphatic organs of the female pelvis can be thought as potential defenders against infections or cancer. However, they can be involved by metastases at any stage of their development, an event that testifies an intrinsic immune immaturity. Also, this secondary neoplastic colonization can be suspected as a key step towards peritoneal carcinomatosis, because the tertiary lymphatic organs can integrate in the lymph dynamics of the female pelvis and peritoneal cavity.