Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

6. Groin Pain Etiology: The Inguinal Hernia, the Occult…
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Lipoma
Epidemiology/Etiology Lipoma of the spermatic cord and round ligament
is understood as an extension of the preperitoneal fat, and not as a
true benign neoplasm, in the majority of the anatomical and surgical
literature. The pathogenesis is largely unknown, but it is thought that
this projection of fat through the deep inguinal ring may cause it to dilate
and predispose one to indirect hernia. These cord lipomas most often do
not have a peritoneal sac, but can nonetheless cause symptoms identical
to that of a groin hernia [ 18 ]. By this definition of cord lipoma, they are,
in effect, all “indirect” in nature. Spermatic cord lipomas as direct extensions
of preperitoneal fat were found in the absence of a hernia with an
incidence of 36–75 % on male autopsies, and lipomas of the cord and
round ligament are found with an incidence of 21–73 % during herniorrhaphy
[ 19 , 20 ].
These lipomas have often been considered as an incidental finding at
the time of hernia repair. One such study by Carilli et al. showed that
there was a 72.5 % incidence of incidental cord lipoma found with an
indirect hernia at the time of open repair [ 21 ]. The incidence of cord
lipoma was greater with larger hernias, and it has also been suggested
that excessive body weight may predispose one to such a lipoma [ 21 ].
Cord or round ligament lipoma occurring in conjunction with an
inguinal hernia is more likely to be missed when performing laparoscopic
herniorrhaphy, especially TAPP repair [ 22 ]. There are often times
when TAPP repair is to be performed for a clinically palpable mass, and
upon visualization, the peritoneum appears normal. In these several
instances, incision of the peritoneum and exploration have revealed an
inguinal cord lipoma [ 19 ]. This raises the question of the significance of
potentially overlooked lipoma in relation to groin pain with the increasing
popularity of laparoscopic herniorrhaphy [ 23 ]. These lipomas do
occur with significant incidence, and they can cause hernia-type symptoms
even without the presence of a true inguinal hernia [ 18 ]. It is often
important to remember the potential presence of a lipoma if a patient is
still experiencing pain after inguinal herniorrhaphy, especially when
done laparoscopically.
Diagnosis Spermatic cord lipomas are diagnosed in much the same
way as an inguinal hernia. On imaging studies, they may be misdiagnosed
as inguinal hernia. As they consist of preperitoneal fat, lipomas
of the round ligament or spermatic cord are not reliably diagnosed