Does perineural invasion of the myenteric plexus have a key role in annular rectal invasion and digestive system symptoms of prostate carcinoma patients?

Prostate carcinoma is one of the most common cancers globally. It relatively rarely invades the rectum, accounting for only about 4% of resected cases. About half of these cases of rectal invasion show an annular rectal stricture pattern. It has been hypothesized that anatomical structures, namely Denonvilliers fascia, may play an important role in annular rectal involvement of prostate carcinoma. Here, we propose another hypothesis: the reason for annular rectal invasion by prostate carcinoma is its extension along the myenteric plexus (Auerbach's plexus). We illustrate this using a case presentation and description of the symptoms of such cases. From a review of the literature, autonomic digestive system symptoms of rectal invasion of prostatic carcinoma, such as diarrhea, tenesmus, or fecal incontinence is seen in about half of cases, coinciding with the frequency of annular rectal invasion. Thus, by modifying the long-established hypothesis, our suggestion that prostate carcinoma spreads along the myenteric plexus when cancer cells invade beyond the Denonvilliers fascia to the rectum could explain the cause and frequency not only of the annular rectal invasion but also the digestive system symptoms related to this disease. The prognosis of prostate carcinoma invading the rectum is very poor; however, this new hypothesis might shed light on the digestive system symptoms associated with prostate carcinoma and might lead to recognition and treatment of these cases at a relatively early stage of rectal invasion.