Salpingitis isthmica nodosa

Salpingitis isthmica nodosa (SIN) (sometimes also referred to as perisalpingitis isthmica nodosa - PIN) refers to nodular scarring of the fallopian tubes. In very early stages, the tubes may appear almost normal. As scarring and nodularity progresses, the changes become more radiographically apparent.

Pathology

Aetiology

• the aetiology of SIN has remained a matter of controversy since its first description
• the prevailing theories include an inflammatory (salpingitis), a congenital, and more recently an acquired (but not post-inflammatory) aetiology

Location

It can involve the entire fallopian tube, but usually involves the proximal two-thirds of the fallopian tube.

Radiographic features

An accurate radiographic diagnosis is important due to its strong association with infertility and ectopic pregnancy.

Hysterosalpingography (HSG)

A characteristic finding is multiple nodular diverticular spaces involving the fallopian tubes (usually involving the proximal two-thirds of the fallopian tubes).

HSG of the nodular area with severe SIN shows several pockets (diverticulae) containing the introduced contrast material ⁵.

It is observed that no dominant channel is seen as the contrast flows through the tube. This means there appears to be no direct pathway for sperm to travel which increases the chances of a tubal pregnancy.

Treatment and prognosis

Complications

• increased risk of tubal ectopic pregnancy ⁴
• subfertility

History and etymology

The term is derived from salpingitis for inflammation of the salpinx (tube), isthmica for involvement of the proximal isthmic portion of fallopian tube and nodosa for its nodular appearance.

Differential diagnosis

Considerations include:

• tubal tuberculosis ⁶ 
  • often has multiple multiple constrictions can form along the course of the fallopian tube can form because of scarringdue to scarring, and give rise to a "beaded" appearance to theof the tubes on HSG
  • can also have adnexal calcification