An unusual pelvic mass in a 43-year-old woman

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Ultrasound revealed a 14-cm round, smooth, solid, nonseptate mass.
Ultrasound revealed a 14-cm round, smooth, solid, nonseptate mass.

Treatment course and definitive diagnosis

Sally was subsequently scheduled for surgical removal of the large ovarian mass. Dermoid cysts are often removed laparoscopically, but due to the size of this mass, an open procedure was required using a Pfannenstiel incision. A 14.2-cm, 502-gram smooth growth was removed and sent intact to pathology. Pathologic examination revealed clumping fragments of hair and teeth surrounded by a large amount of mucoid tissue that was diagnostic of a teratoma, or dermoid cyst. Microscopic examination of multiple tissue fragments verified that the mass was negative for any malignancy. Final pathology diagnosis was a cystic teratoma, also known as a dermoid cyst or germ cell tumor.

Discussion

Clinical feature and epidemiology. Given Sally's age and otherwise unremarkable history, the differential diagnosis of any pelvic mass includes endometrioma, tubo-ovarian abscess, pedunculated uterine fibroid, hydrosalpinx, ectopic pregnancy, renal pelvic cyst, and peritoneal cyst.

Any such adnexal mass requires definitive evaluation. Often, the speed of onset, level of pain, and vital signs direct the initial workup. The following masses pose the most concern:

  • Those that have a complex internal structure on imaging 
  • Those that have solid components 
  • Those that are associated with pain 
  • Masses in prepubescent or postmenopausal women 
  • Large cysts, typically defined as those unilocular cysts greater than 10 cm, have been monitored with the watchful waiting approach. Any complex cyst in a postmenopausal woman should be regarded with increased suspicion, regardless of size. 

Cystic teratoma is the most common ovarian tumor, accounting for up 10% to 20% of all ovarian tumors.1 These most frequently occur in females aged 15 to 40 years, which are the primary reproductive years.2 Of special note, at least 50% of cancerous adnexal neoplasms in adolescent females are mature cystic teratomas that become malignant.3 

A dermoid cyst of the ovaries develops from a totipotential cell, which is a primary oocyte that retains the capability to form all kinds of body tissues. A dermoid cyst is so-named because it has cell walls that are the same as those of the outer skin. These encapsulated tumors are frequently composed of complex structures formed from 1 or more of the 3 germ cell dermal layers. They may be organized with well-differentiated ecto- and meso-dermal tissues surrounding endodermal structures or very disorganized.  They may also comprise tissues normally present in layers of skin, including hair follicles, sebaceous or skin oil, and sweat glands. These tissues and glands continue to secrete their normal substances, which collect inside the cyst, causing it to enlarge and grow. Consequently, structures such as hair, teeth, or bones may be found inside these cysts. Smaller teratomas are often found incidentally during routine pelvic examinations. Because of the often bizarre appearance of the contents of these cysts, their name, teratoma, is derived from the Greek “teras,” meaning monster. Although typically unilateral, documentation of bilaterally occurring tumors indicates an 8% to 14% occurrence. 

The overall course of discovery and removal of these tumors is usually uneventful. Even in the rare cases of malignant transformation, surgical resection alone has usually been proven to be successful in disease eradication due to their encapsulated structure.3 

Complications. The main complication arising from an ovarian dermoid cyst, occurring in 3% to 11% of patients, is torsion.4 Though somewhat counterintuitive, statistics show that the risk of torsion increases with the size of the structure. Spontaneous rupture is also a potentially life-threatening complication with a reported incidence of 1% to 2.5%. Rupture, by nature, occurs abruptly and leads to hemorrhagic shock and peritonitis. Although these tumors are usually benign, they can undergo transformation to malignancy. This is most common in tumors with predominantly squamous components and is only found in 0.2 to 2.0% of cases. When the dermoid cyst is malignant, a squamous cell carcinoma is the usual cell type. 

Conclusion and follow-up

Sally had an uneventful postoperative course with complete recovery in 6 weeks. Her nagging discomfort and complaints of abdominal enlargement and change in bowel habits were completely resolved. She was released to return to her normal lifestyle following her surgical discharge.

Sherril Sego, FNP-C, DNP, is an independent consultant in Kansas City, Mo.

References

  1. Hamilton CA. (2012). Cystic teratoma. Available at: http://emedicine.medscape.com/article/281850-overview
  2. Kim MJKim NYLee DYYoon BKChoi D. Clinical characteristics of ovarian teratoma: Age-focused retrospective analysis of 580 cases. Am J Obstet Gynecol. 2011;205(1):32.e1-4.
  3. Biskup WCalaminus GSchneider DTLeuschner IGöbel U. Teratoma with malignant transformation: experiences of the cooperative GPOH protocols MAKEI 83/86/89/96. Klin Padiatr. 2006;218(6):303-308.
  4. Benjapibal M, Boriboonhirunsarn D, Suphanit I, Sangkarat S.  Benign cystic teratoma of the ovary: a review of 608 patients. J Med Assoc Thai.  2000;83(9):1016-1020.
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