Can endometriosis grow in the shoulder muscles?

Question

Hi doctor,

I am concerned, and I wanted clarity on these:

Can endometriosis grow inside a 45-year-old woman’s trapezius muscle and cause shoulder pain?
If yes, how does endometrial tissue reach such distant muscles?
Is this extremely rare or something that doctors do consider when evaluating unexplained cyclical pain?

Kindly help.

Thank you.

Answer 1

Hi,

Welcome to icliniq.com.

I have read your query and understand your concerns.

Yes, endometriosis can grow inside a trapezius muscle, although it is an extremely rare location for the disease.

Cases of extra-pelvic endometriosis, including those in musculoskeletal tissues like the trapezius, shoulder-neck, and upper limbs, have been documented, generally affecting women of reproductive age. The incidence and symptoms of it reduce as a woman gets close to her menopausal period.

The most likely mechanism for musculoskeletal (trapezius muscle) endometriosis is the dissemination of endometrial cells through the bloodstream or lymphatic system. Cells travel from the uterus to distant sites and implant themselves in tissues, including muscle fascia.

While the average age for musculoskeletal endometriosis in one study was 34 years, it is well within the 17 to 49 age range reported in cases. Endometriosis is estrogen-dependent, so it can persist until menopause.

So, trapezius endometriosis is a known condition. It is, however, very rare; thus, it will take a very high index of suspicion before a doctor will consider it. Also, the patient, in most cases, would have features suggestive of pelvic endometriosis.

I hope my answer is clear to you, and please do not hesitate to ask any questions at any time.

Thank you.