USG & ovarian mass character / nature

Complex   masses  contain both fluid and solid  areas, They can be  predominantly   cystic or predominantly solid . Ovarian   tumors that    contain   solid components   or irregular  septations e.g.  dermoid cysts and most  common surface   epithelial    stromal   ovarian   tumors of a serous mucinous and endometrioid   subtype  are usually   classified into this  complex  mass category.

Dermoid cysts

Mature cystic teratomas  of the ovary  or   dermoid  cysts are  the most common benign germ cell tumor  and  the most   common ovarian neoplasm   constituting 5-25%  of all ovarian neoplasms . They   occur  most commonly during the   reproductive years. Unlike  other germ cell  tumors of the ovary    however  they have a wider age distribution and may be encountered  from infancy  to old age.

A dermoid  cyst is composed  of well  differentiated   derivates of the three  germ  layers ectoderm mesoderm  and endoderm with ectodermal elements   predominating   . In   its pure form it is  benign   but a malignant transformation  in one of  its elements can occur   in approximately 2%  of the cases.

In 8-15%  of the cases  the ovarian   dermoid  cysts are   bilateral with  the possibility of several  tumors  being present  in the same ovary  . Grossly   the tumors   vary in size from 0.5 cm to more than 40 cm   . approximately  60 %   measure   5-10 cm in diameter   and more  than 90 %  measure   less than 15 cm in diameter  . The cut surface  of the tumor    reveals   a cavity  filled with fatty  material  similar to   normal   sebum and hair surrounded  by a firm  capsule of varying  thickness . It is   usually    unilocular   but may also be  multilocular.

Usually  a single  but possibly a multiple   protuberance    arises  from the cyst   wall and projects  into the lumen. The protuberance is most commonly solid and  consists of a variety of different   tissues. The hair  present  in the tumor  arises   from this protuberance and bone  or teeth when present   tend to be located  within  this area.

Dermoid   cysts are often discovered as an incidental  finding . when  symptomatic they  usually present  with abdominal  pain abdominal mass or  swelling and abnormal   uterine  bleeding.

Sonographic  features   ascribed  to dermoid   masses  include  the presence  of regional  diffuse bright   echoes  with or without   posterior acoustic   shadowing   hyperechoic   lines and dots  shadowing  echo density   and a fluid – fluid   level.

Kurjak et  al using  a morphologic   scoring system   for dermoid   cysts achieved   a sensitivity  and specificity   of 93.1%   and 99.4%   respectively in a study  of 887   adnexal masses. When the presence  of vascularity   was assessed using   color Doppler  72%   of cystic   teratomas  were mostly avascular which   when combined  with the scoring   system  produced a sensitivity and specificity  of 99.02%   and 99.75% respectively.