4 min readNew DelhiMar 7, 2026 12:00 AM IST
Endometriosis is widely understood as a condition affecting women, but emerging conversations in medical education are highlighting that biology does not always fit neatly into expected categories. London-based general physician Dr Sermed Mezher recently addressed this little-known phenomenon in a video shared on Instagram, explaining that medical literature has recorded rare instances of the condition in biological males.
He noted that fewer than 20 such cases have been documented historically. He said, “In these instances, endometrial-like tissue, which normally lines the uterus, is found growing in locations such as the bladder, abdominal wall, or inguinal canal. The presence of this tissue in a male body is a biological anomaly that challenges some of the traditional theories regarding how the disease originates and spreads.”
The physician further described how early embryonic development may help explain these rare cases. He explained, “Early in life, around six weeks after our foray from fertilisation, all of us develop something called a Müllerian duct, and in females, these go on to produce their reproductive systems. In males, however, the production of anti-Mullerian hormone causes these to regress. And the theory goes that remnants of these Müllerian ducts can actually become reactivated after exposure to oestrogen.”
He added, “The prevailing theory for these rare occurrences is often linked to hormonal cross-talk or high levels of oestrogen exposure. Many of the recorded cases involved men who were undergoing prolonged oestrogen therapy for prostate cancer or individuals with severe liver cirrhosis, which can lead to an inability to properly metabolise oestrogen. Scientists believe that these high oestrogen levels may trigger the transformation of vestigial embryonic cells, known as Mullerian duct remnants, into endometrial-type tissue.”
He also pointed out that men with obesity or advanced liver disease may have altered hormone levels that increase circulating oestrogen, potentially raising risk. Despite its rarity, the condition can present with symptoms such as severe cramping, persistent abdominal pain and bloating, offering researchers new insight into how hormones and genetics may influence endometriosis more broadly.
So, given how rare endometriosis in biological males is, what should clinicians and patients look out for?
Dr Palleti Siva Karthik Reddy, senior consultant in internal medicine, Bengaluru, tells indianexpress.com, “Since male endometriosis is exceptionally rare, it is rarely the first suspect. Clinicians should look out for unexplained, chronic lower abdominal or pelvic pain, or occasionally, blood in the urine. The biggest red flag for investigation is a history of significant oestrogen exposure. This often stems from prolonged oestrogen therapy for conditions like prostate cancer or from medical transitions.”
He adds that secondary causes of hormonal imbalance, such as severe liver cirrhosis or profound obesity, both of which alter how the body processes oestrogen, are also key risk factors. In many documented cases, patients actually show no distinct symptoms, and the endometrial-like tissue is discovered entirely by accident during surgeries for hernias or prostate issues. Ultimately, if a male patient with a high-estrogen background presents with persistent, unexplained pelvic discomfort, this rare anomaly shouldn’t be entirely ruled out.
What can these rare cases teach us about the underlying causes of endometriosis more generally?
These male cases are completely fascinating because they challenge the longstanding “retrograde menstruation” theory, the idea that endometriosis is primarily caused by menstrual blood flowing backwards into the pelvis. “Since biological men do not menstruate, their cases lend massive credibility to the embryonic and metaplasia theories, which suggest the disease begins with cellular remnants reacting to hormonal triggers,” states Dr Reddy.
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For the wider population, he notes, this shifts the narrative. “It reframes endometriosis from a mechanical ‘menstrual plumbing’ issue to a complex systemic, cellular disease. Understanding this could eventually steer wider treatment strategies away from just suppressing periods or relying purely on surgical excision. Instead, future diagnostics and therapies could focus heavily on identifying embryonic cellular markers and developing highly targeted hormonal regulators, paving the way for far more personalised treatments,” stresses Dr Reddy.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
