In the past, I’ve researched how Endometriosis can affect the renal system, specifically the bladder or ureters, and how that could even cause blockages that cause kidney issues and severe problems.

Today, I’m going to talk about Endometriosis and the actual kidney.

A study published in October of 2018 discussed a 45-year-old woman who had flank pain and blood in her urine.  Imaging studies found a mass on her left kidney.  A surgery was performed to remove the suspected renal mass and a portion of her kidney, and pathology confirmed it was an Endometriosis lesion.  It was removed from her “renal parenchyma,” which is the solid part of the kidney that filters blood and makes urine.

My mind was blown!!

That one little abstract led me down a rabbit hole: how many others out there have had Endometriosis lesions on or inside of their kidneys…not just the bits and pieces and tubes leading up to our bean-shaped organs?

But before I get into the studies of women who had Endometriosis growing on (or inside) their kidneys, I want to outline the symptoms of what renal Endometriosis may feel like:

The Symptoms

Here’s a list of symptoms I’ve been able to find that have been associated with renal Endometriosis (you may suffer from some or none of these):

• Blood in urine
• Flank pain
• Renal colic (pain that may feel like you have kidney stones)
• Lower back pain
• Symptoms may (or may not) get worse during menstruation
• Swelling
• Uretal obstruction
• Some people had zero symptoms

As always, keep track of all of your symptoms, your pain, any triggers, and the timeline of when these symptoms appear.  It’s very important to walk in with tangible proof of your symptoms.  And, as always, these symptoms may also be signs of sooooo many other things.  It may not be Endometriosis affecting your renal system, but then again…it may.  Don’t discount it.  Please, talk to your doctor.

Published Studies of Endometriosis on the Kidneys

Besides the study referenced above, here are more examples of Endometriosis being found involving kidneys.  I could no locate several studies that were published between 1950-1970, but I still found plenty!

Be advised: renal Endo is considered incredibly rare!  That being said, feel free to print out any examples in the Resources section below if you’re wanting to talk to your doctor about it.  As mentioned in one study, “…endometriosis of kidney is a rare manifestation of a common disease.”  But be aware that it can happen.  Track your symptoms. And always talk to your doctors.

The first known published case of Endometriosis inside the kidney came out in 1943…seventy-five years ago!  Victor Marshall did a lot of research prior to publishing his study and couldn’t find any references to Endo inside the kidney, but did refer to a prior case with an instance of cells that might be Endometriosis on the exterior of the kidney.  But, back to Mr. Marshall’s case at hand:  a 40-year-old woman sought medical care.  Sixteen months prior, she developed a small mass in her upper left torso; six months later, she had complaints of constant swelling and left flank pain.  Sometimes the bump was tender, but her symptoms didn’t increase or decrease around her period.  Two months later, she vomited what she thought was blood.  A few months later, she found herself at Dr. Marshall’s clinic.  The chest and GI x-rays were normal, but the pyelogram (a type of imaging study) showed her left kidney was enlarged, deformed, and functioning less.  She was admitted to the hospital for further care.  The physical exam revealed a round firm mass where she told them it was.  Her lab results, including her urine tests, were all normal.  Surgery was performed.  The mass in the kidney oozed “old bloody fluid,” when it was pierced and they decided to remove her kidney.  Biopsy revealed several cysts inside, one of which oozed 500cc of “dark brown old blood.”  I had to look up how many ounces 500cc was.  Are you ready?  16 ounces!  That’s MORE than a 12-ounce can of soda!  All of the pathologists who reviewed the lesions inside the kidney agreed:  it was “endometrium tissue.”

A 1950 entry in The Journal of Urology is about a 29-year-old woman in 1948 who checked into a local Chicago hospital because of blood in her urine, which had occurred on and off for the past three months.  In 1946, she also had blood in her urine but it lasted for only two weeks.  Her symptoms did not coincide with her period and didn’t seem cyclical in nature.  A physical examination revealed nothing abnormal about her kidneys or abdomen.  Urine tests were positive for red blood cells. An x-ray (excretory urogram) was performed: the left kidney appeared normal, but they had a hard time visualizing the right kidney.  A cystoscopy revealed the bladder was normal.  A pyelogram found the right kidney had abnormalities.  Surgery was performed and  showed several bulging areas which had cysts, one of which was drained of 20cc of “chocolate colored fluid.”  At that point, her entire right kidney was removed.  Pathology confirmed Endometriosis.  Slides of the kidney tissue were also presented at a seminar of pathologists and the group agreed with the renal endometriosis diagnosis.  By 1950, the patient had no recurrence of symptoms.

In 1969, a 43-year old woman was admitted to a Nevada hospital for blood in her urine that had been on and off for the past three months.  She had a history of heavy and painful periods and received a surgically-confirmed Endometriosis diagnosis seven years ago.  A cystoscopy and pyelogram confirmed bloody urine was coming from her right ureter.  A large defect was also visualized on her right kidney (it was a presumed blood clot since it appeared full of blood) and a renal tumor was also observed.  Surgery was performed and they removed her right kidney and most of her right ureter.  Many small cysts were found inside the kidney, and each contained bloody fluid.  The tumor on her kidney was akin to an endometrial polyp.  There was no Endometriosis located within her ureter that was removed.  She continued to treat with her gynecologist for her Endometriosis and was placed on hormone therapy.

A 1976 study was published of a 23-year-old woman who complained of lumbar pain.  Four years earlier, she had a urinary tract infection and two prior kidney infections.   A year before she was admitted into the hospital, she complained of tenderness around her right kidney.  She was treated with antibiotics, but it didn’t diminish her pain. In fact, her lower back pain worsened and became constant.  Imaging studies of her right kidney showed a mass on her kidney.  Surgery was performed.  The 3cm mass was punctured and oozed yellow pus, which later tested positive for E. Coli presence.   While examining her kidney, another mass was found, which was a suspected clear cell carcinoma.  They removed her right kidney.  Pathology found the mass to be Endometriosis.  Since her surgery, she was symptom-free.

In 1980, a 40-year-old woman had a dull, aching pain in the right side of her body, just below her rib cage, for five to six months.  She had no other symptoms.  During a physical examination, a mass was found in her right loin.  An pyelogram was taken and showed excess fluid and loss of function of her right kidney.  Surgery was performed and her kidney was found to be enlarged.  A “glistening membranous” cyst was on her kidney wall.  Surgeons removed her kidney and biopsied the abnormality.  The cyst was filled with a “brownish gelatinous membranous fluid” (sound familiar?) and it was diagnosed that she had an Endometrioma on her kidney.

The British Journal of Obstetrics & Gynaecology published a study in 1991 about a 25-year-old woman.  In 1981, she had blood in her urine, but all tests came back normal.  Over the next three years, the presence of blood was a daily occurrence.  She also developed back pain, which got gradually worse.  Her symptoms were worse after physical activity but didn’t seem to heighten when on her period.  In 1984, imaging studies found a possible tumor on her left kidney.   A puncture test was conducted on the cyst and renal Endometriosis was suspected from the pathology results.  The young woman was referred to a gynecologist.  She underwent a laparotomy and her surgeon discovered an endometrioma on her ovary; it was excised.  No other Endometriosis was located in her pelvis or abdomen.  After surgery, she received birth control pills, which she took for six months and her period stopped.  However, blood persisted in her urine.  Four months after she stopped the birth control pills, her back pain once more became severe and she continued to have blood in her pee.  She had a laparoscopy performed and there were three 1mm endometriomas discovered.  She was given Nafarelin (a GnRH agonist) for the next 11 months.  By the fourth week of treatment, the blood in her urine and her back pain stopped.  Once she stopped the Nafarelin she had another exploratory laparoscopy, in which no Endometriosis was discovered.  But two months later…her urine once more contained blood.  A CT scan showed a new cyst at the site of the original one on her left kidney.  Another puncture test was performed, but the results came back normal.  Three months later, she once more had constant blood in her urine and a recurrence of her low back pain.  She was once more placed on Nafarelin for another eight months.  After the first month of use, she was symptom-free and remained so at the time the study was published.

In 2006, a study was published in Saudi Medical Journal about a 38-year-old gal who had abdominal pain for about two months.  She didn’t have any history of painful periods, urinary symptoms, or irregular periods.  She was described as presenting as “toxic, sick looking” and feverish.    Imaging studies found an ovarian mass and an exploratory laparotomy was performed.  Her right kidney was enlarged and had lesions on it and her right ureter had dilated.  Surgeons removed her inflamed fallopian tubes and both ovaries.  They also took a sample of the kidney lesions.  Pathology confirmed that her ovary and the kidney lesions were Endometriosis.  After the surgery, she responded well to Danazol treatments.

A 2009 report is about a 46-year-old woman who complained of three months of lower back pain.  The pain wasn’t worse on her period.  Physical examination and palpitation revealed a mass in her left upper abdomen.  Urine analysis and blood tests were normal, but an ultrasound and CT scan confirmed a mass on her lower left kidney.  They believed she had a hematoma on her kidney and inserted a catheter (for six days) to drain it.  The mass shrank a bit after the drainage but didn’t disappear.  She had a follow-up visit scheduled for a month later but had to be admitted to the hospital prior to that date because of left thigh pain that caused her issues with walking, nausea, and vomiting.  She underwent a surgery to look at her kidney; the hematoma mass was removed from beneath the surface membrane of the kidney and biopsied.  She received a renal Endometriosis diagnosis; the Endometriosis was lodged beneath the hematoma.  There was no recurrence of symptoms a month after her surgery.

Now hold onto your hats…a 2012 study was about a 13-year-old girl!  This child had blood in her urine and suffered from cramps while peeing, pain in her lower back (more on the right side), and vomiting.  Her symptoms had been on and off for about two years and were worse around her period.  Imaging studies led the doctors to believe she had a kidney stone.  Upon physical examination, her abdomen was somewhat swollen and she had some tenderness near her belly button.  She underwent a barrage of tests and multiple various imaging studies.  The kidney stone diagnosis was replaced with a renal Endometriosis diagnosis.  The clinic did not want to conduct surgery to confirm their suspicions, though (they opine that invasive techniques on teenagers isn’t justified).  She was released and told to seek a surgery consult.  The authors do state, however, that her medical history, symptom history, the fact that it follows her period, and the nodule that showed up her kidney in imaging studies was enough to confirm their suspicions.  (This study was roughly translated from Russian to English and I fear I’ve missed immense details).

In 2013, a woman complained of sudden right flank pain.  She had a history of painful periods and lower back pain.  A mass was felt in the right upper quadrant of her abdomen and a CT scan confirmed the presence of a “huge” renal tumor on her right kidney.  She received two months of conservative treatment, but the tumor did not recede.  Surgery was performed, her kidney was removed, and a biopsy confirmed it was Endometriosis.  Afterward, she was prescribed Danazol and had no recurrence at her 10-month follow-up.  (Sidenote: there’s a photo of the inside of her kidney showing the cysts within…)

Published in 2015 in the International Surgery journal, one study followed a surgery that took place in 2013.  The purpose of this study was to warn others about the misdiagnoses that may occur with renal Endometriosis.  A 37-year-old woman had recurrent dull pain in her right lower back.  The pain worsened during her period for the past six months.  She did not have any blood in her urine or even abdominal pain.  Just back pain.  She also didn’t have a history of painful periods, painful sex, or prior abdominal surgeries. An ultrasound found that she had fluid backed up into her right kidney as well as kidney stones present in the kidney and right ureter.  An x-ray confirmed these findings.  She was given drugs to treat the stones, as well as underwent shock wave therapy.  Neither made her back pain go away.  She was admitted to the hospital in October.  Further x-rays showed the stones were still present, and that her kidney was deformed.  A CT scan showed a mass on the lower right portion of her kidney.  It was thought to have been a tumor.  Surgery was performed to remove her kidney (due to the size of the suspected tumor).  No other lesions or masses were found around her kidney.  When cut, the mass contained “brown, serumlike fluid” within the kidney.  Pathology confirmed that the mass was Endometriosis, and not a tumor after all.

A later 2015 study was about a 53-year-old woman who had gone to the emergency room because of flank pain that she had for several years and she had a mild fever.  An x-ray showed she had stones in both kidneys.  An ultrasonogram also showed that her right kidney was contracted (her kidney appeared scarred and atrophied).  She was admitted for a suspected kidney infection.  A CT scan showed an abscess in her right kidney, too, which invaded into her psoas muscle.  The abscess was drained and three days later her right kidney was removed.  Lesions were found within the kidney and she was diagnosed with renal Endometriosis.   And the patient was symptom-free at her follow-up appointments.

Now what?

This blog entry is not intended to scare you.  It is meant to educate you.  Endometriosis has been documented on and inside the kidneys.

If you fear you may suffer from renal endometriosis, keep track of your symptoms.  That’s crucial.  Bring your diaries and notes and these studies to your physician.  The good news? In all of these studies, a mass was visualized in imaging studies.  And in most cases, a physical mass was felt during a physical examination.

Start there.

Even if you don’t have renal Endometriosis, you really can’t mess around with symptoms of any type of trouble with your kidneys.  Backaches? Abdominal aches?  Blood in your urine?  Run to your doctor…whatever it may be, it’s not normal and may be a sign of something far more detrimental to your health.

Resources:

BMC Research – (Article, Oct. 2015) – Endometriosis in a Kidney with Focal Xanthogranulomatous Pyelonphritis and a Perinephric Abscess

British Journal of Obstetrics & Gynaecology – (Abstract, April 1991) – Renal Endometriosis Treated with Gonadotrophin Releasing Hormone Agonist.  Case Report. (full article may be accessed here)

Child’s Health – (Abstract, 2012) – Renal Endometriosis in a Child (full article may be accessed here…head’s up – it’s in Russian.  I used DocTranslator to read it in English)

Fertility & Sterility – (Abstract, July 2009) – Renal Endometriosis Presenting with a Giant Subscapular Hematoma: Case Report (full article may be accessed here)

Il Giornale di Chirurgia – Journal of Surgery – (Article, Dec. 2017) – Renal Endometriosis Mimicking Complicated Cysts of Kidney: Report of Two Cases

International Surgery – (Article, 2015) – Renal Endometriosis Tends to be Misdiagnosed as Renal Tumor: A Rare Case Report

Journal of Endourology Case Reports – (Abstract, Oct. 2018) – Renal Endometriosis: A Case of an Endometrial Implant Mimicking a Renal Mass (full article may be accessed here)

National Cancer Institute – Anatomy of the Kidney & Ureter

Saudi Medical Journal – (Article, 2006) – A Young Woman with Endometriosis of Kidney

Scandinavian Journal of Urology and Nephrology – (Abstract, March 1976) Renal Endometriosis (full may be accessed here)

The Journal of Neurology – (Abstract, March 1980) – Endometrioma of the Kidney: Case Report (full article may be accessed here)

The Journal of Urology – (Partial article, Dec. 1943) – The Occurrence of Endometrial Tissue in the Kidney (full article may be accessed here)

The Journal of Urology – (Partial article, Oct. 1950) – Endometriosis of Kidney (full article may be accessed here)

The Journal of Urology – (Partial article, Sept. 1969) – Renal Endometriosis Associated with Hematuria (full article may be accessed here)

Urological Science – (Article, March 2013) – Renal Endometriosis Mimicking an Angiomyolipoma

~ Again, I am a layman.  I do not hold any college degrees, nor mastery of knowledge.  Please take what I say with a grain of salt.  If curious, do your own research 😉 Validate my writings.  Or challenge them.  And ALWAYS feel free to consult with your physician. Always.  Yours ~ Lisa