Our knowledge that “urine is sterile” is no longer accepted after the development of a next-generation sequencing (NGS) test. Using NGS, microbiota in the human body were discovered, and it is expected that this will improve our understanding of human diseases. However, the mechanism involved in the effect of the microbiome on diseases is still poorly understood. Associations of gut microbiome with diseases have been recently reported. Based on such associations, bladder–gut–brain axis, gut–bladder axis, gut–vagina–bladder axis, and gut–kidney axis as novel mechanisms of action of the microbiome have been suggested. Each axis can influence the development and progression of disease through interactions. In these interactions, metabolites of the microbiome including short-chain fatty acids (SCFA) and the inflammasome play an important role. Inflammasomes are multiprotein oligomers that can initiate inflammatory responses. Inflammasomes can trigger inflammation and pyroptosis and ultimately contribute to disease development. SCFAs play an important role in immune cell migration, cytokine production, and maintenance of cellular homeostasis. Associations of inflammasomes with systemic diseases such as obesity and insulin resistance have been reported. The roles of inflammasomes and SCFAs in kidney, bladder, and prostate diseases have also been revealed recently.

Metastatic cancers of the paratesticular tissue are very rare; however, the most frequent primary site of spermatic cord metastasis is the gastrointestinal tract. We recently observed two cases of late-onset metastatic adenocarcinoma of the spermatic cord. Both patients complained of groin discomfort with a palpable mass in the scrotum and inguinal area. Radical orchiectomy and adjuvant chemotherapy were performed in both patients. Although the prognosis of patients with metastatic adenocarcinoma of the spermatic cord is typically poor, the prognosis of our patients was favorable after follow-up for 14 to 18 months. In patients with groin discomfort or swelling and a history of gastric cancer, metastatic adenocarcinoma should be included in the differential diagnosis for early detection of tumors.

Yang HJ, et al. World J Mens Health. 2023 Jan;41:e18. https://doi.org/10.5534/wjmh.220171

Koh SK, et al. J Korean Med Sci. 1992 Jun;7(2):136-140. http://dx.doi.org/10.3346/jkms.1992.7.2.136