BACKGROUND
A 26-year-old sexually active woman presents to her primary care physician with an insidious onset of dull pelvic pain. The pain is of moderate intensity and has lasted for approximately the past year. Her last menstrual period was about 2 weeks ago and was normal. She denies experiencing fever or weight loss, vaginal discharge or abnormal bleeding, or urinary symptoms such as dysuria or increased frequency. She reports a normal bowel movement pattern.
A 26-year-old sexually active woman presents to her primary care physician with an insidious onset of dull pelvic pain. The pain is of moderate intensity and has lasted for approximately the past year. Her last menstrual period was about 2 weeks ago and was normal. She denies experiencing fever or weight loss, vaginal discharge or abnormal bleeding, or urinary symptoms such as dysuria or increased frequency. She reports a normal bowel movement pattern.
The patient is on birth control pills, but otherwise, she does not take any medications and has no significant past medical history.
On physical examination, the patient has normal vital signs and is in no apparent distress. The abdominal examination reveals fullness in the left lower quadrant with no tenderness to palpation. A large, palpable mass is noted in the left adnexa during the pelvic examination. There is mild tenderness associated with palpation of the mass. There is no cervical discharge noted, the right adnexa are not palpable, and there is no tenderness to palpation. The urine pregnancy test is negative, and findings on an urinalysis are normal.
A transvaginal pelvic ultrasound is obtained (Image 1). The results demonstrate a 4.9 X 8.1 cm complex echogenic mass posterior to the bladder. The patient undergoes subsequent imaging with a CT scan of the abdomen and pelvis (Image 2).
What is the diagnosis?
On physical examination, the patient has normal vital signs and is in no apparent distress. The abdominal examination reveals fullness in the left lower quadrant with no tenderness to palpation. A large, palpable mass is noted in the left adnexa during the pelvic examination. There is mild tenderness associated with palpation of the mass. There is no cervical discharge noted, the right adnexa are not palpable, and there is no tenderness to palpation. The urine pregnancy test is negative, and findings on an urinalysis are normal.
A transvaginal pelvic ultrasound is obtained (Image 1). The results demonstrate a 4.9 X 8.1 cm complex echogenic mass posterior to the bladder. The patient undergoes subsequent imaging with a CT scan of the abdomen and pelvis (Image 2).
What is the diagnosis?
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HINT
This is the most common benign ovarian tumor.
This is the most common benign ovarian tumor.
Author:
Gautam Dehadrai, MD,
Staff Radiologist,
Department of Radiology,
Veterans Affairs Medical Center,
Albuquerque, NM
eMedicine Editors:
Erik D. Schraga, MD,
Department of Emergency Medicine,
Kaiser Permanente,
Santa Clara Medical Center, Calif
Rick G. Kulkarni, MD
Assistant Professor,
Yale School of Medicine,
Section of Emergency Medicine,
Department of Surgery,
Attending Physician,
Medical Director,
Department of Emergency Services,
Yale-New Haven Hospital, Conn
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ANSWER
Ovarian dermoid cysts: an ovarian dermoid cyst, or a mature cystic teratoma, is a type of teratoma that is the most common of ovarian tumors, accounting for about 10-20% of all ovarian neoplasms. Ovarian dermoid cysts usually occur in the reproductive age group, and they may be bilateral in 8-15% of cases. An ovarian dermoid cyst is typically benign and is derived from 2 or more of the 3 germ layers: the ectoderm, the endoderm, and the mesoderm. These tumors generally maintain an orderly arrangement, with well-differentiated ectodermal and mesodermal tissues surrounding endodermal components. As a result, these cysts are most frequently lined by skin with sweat and sebaceous glands and contain greasy, yellow sebaceous material mixed in with hair follicles and hair. Less commonly, cartilage, bone, thyroid tissue, and other structures may be found within ovarian dermoids.
The word teratoma is derived from the Greek word teraton, meaning monster, and was used initially by Virchow in the first edition of his book on tumors, which was published in 1863. Arising from totipotential cells, these tumors are typically midline or para-axially situated, with the most common locations being sacrococcygeal (57%) and gonadal (29%) (both in the ovaries as well as the testes). Other locations include mediastinal (7%), retroperitoneal (4%), cervical (3%), and intracranial (3%). An ovarian dermoid cyst can range from a benign, well-differentiated (mature) cystic lesion, as in this case; to lesions that are monodermal and essentially devoid of organization; to those that are solid and malignant (immature).
Although ovarian dermoids can be found incidentally during radiographic studies or during abdominal surgery for other indications, these tumors also commonly present with an insidious onset of increasing mild to moderate abdominal pain and fullness. The onset of abdominal and pelvic pain can be acute if torsion of the affected ovary occurs. In 15% of cases, the symptoms are associated with menstrual abnormalities. Complications other than torsion for an ovarian dermoid cyst include rupture with chemical peritonitis and suppuration. The malignant transformation of an ovarian dermoid cysts is very rare, with an incidence of approximately 1-2% of all ovarian dermoids. The more common scenario is the malignant transformation of certain elements (most commonly squamous components) of highly specialized or solid dermoids. The most common malignancy in both ovarian dermoid cysts and other types of teratomas is squamous cell carcinoma. If malignant transformation does occur, the prognosis is poor.
Ultrasound appearances are often characteristic because of the presence of a highly echogenic dermoid plug (Rokitansky nodule), which is the solid element within the cyst that contains hair follicles, sebaceous glands, fat, and calcified elements. Fluid-fluid levels can also be seen. Ovarian dermoids are the most commonly missed ovarian neoplasms on sonography, often due to the "tip of the iceberg" sign, in which the back wall of the cyst is obscured by acoustic shadowing. As a result, the echogenic Rokitansky nodule may be misinterpreted as bowel gas. Differential diagnosis on ultrasound includes tubo-ovarian abscesses, which can also contain fluid-fluid levels and echogenic pus that can produce acoustic shadowing caused by gas formation. Ectopic pregnancies also demonstrate shadowing from bone and contain echogenic hemorrhage. Other conditions in the differential diagnosis include other benign or malignant ovarian neoplasms, endometriomas, pedunculated uterine fibroids, hydrosalpinges, pelvic kidneys, and peritoneal cysts.
The diagnosis of ovarian dermoid cysts using computed tomography (CT) and magnetic resonance imaging (MRI) is fairly straightforward, as these imaging modalities are better able to identify and distinguish the multiple specific densities within the masses. On a CT scan, fat attenuation within a cyst, with or without calcification in the wall, is diagnostic for ovarian dermoid cysts. A floating mass of hair can also sometimes be identified at the fat–fluid interface. Using MRI, the sebaceous component of dermoid cysts can be identified with very high signal intensity on T1-weighted images. The signal intensity of the sebaceous component on T2-weighted images is variable, usually approximating that of fat. Chemical-shift artifacts in the frequency-encoding direction can also be used to detect fat and distinguish it from a hemorrhage.
As a result of the potential for complications, such as torsion and rupture, dermoids are usually resected when found. Gynecologic referral is recommended upon diagnosis, as was done for this patient. In most cases, a simple cystectomy is preferred, with many gynecologists choosing laparoscopy as an acceptable alternative to laparotomy in resection because of reductions in postoperative pain, blood loss, and length of hospital stay. Some studies have found an increased intraoperative spillage rate with laparoscopy, while others have not. There is a 4% risk of recurrence after resection.
To learn more about ovarian dermoid cysts, please visit the eMedicine articles Teratoma, Cystic and Ovarian Cysts in the Medicine, Ob/Gyn, Psychiatry, and Surgery section, and Dermoid Cyst in the Dermatology section.
Ovarian dermoid cysts: an ovarian dermoid cyst, or a mature cystic teratoma, is a type of teratoma that is the most common of ovarian tumors, accounting for about 10-20% of all ovarian neoplasms. Ovarian dermoid cysts usually occur in the reproductive age group, and they may be bilateral in 8-15% of cases. An ovarian dermoid cyst is typically benign and is derived from 2 or more of the 3 germ layers: the ectoderm, the endoderm, and the mesoderm. These tumors generally maintain an orderly arrangement, with well-differentiated ectodermal and mesodermal tissues surrounding endodermal components. As a result, these cysts are most frequently lined by skin with sweat and sebaceous glands and contain greasy, yellow sebaceous material mixed in with hair follicles and hair. Less commonly, cartilage, bone, thyroid tissue, and other structures may be found within ovarian dermoids.
The word teratoma is derived from the Greek word teraton, meaning monster, and was used initially by Virchow in the first edition of his book on tumors, which was published in 1863. Arising from totipotential cells, these tumors are typically midline or para-axially situated, with the most common locations being sacrococcygeal (57%) and gonadal (29%) (both in the ovaries as well as the testes). Other locations include mediastinal (7%), retroperitoneal (4%), cervical (3%), and intracranial (3%). An ovarian dermoid cyst can range from a benign, well-differentiated (mature) cystic lesion, as in this case; to lesions that are monodermal and essentially devoid of organization; to those that are solid and malignant (immature).
Although ovarian dermoids can be found incidentally during radiographic studies or during abdominal surgery for other indications, these tumors also commonly present with an insidious onset of increasing mild to moderate abdominal pain and fullness. The onset of abdominal and pelvic pain can be acute if torsion of the affected ovary occurs. In 15% of cases, the symptoms are associated with menstrual abnormalities. Complications other than torsion for an ovarian dermoid cyst include rupture with chemical peritonitis and suppuration. The malignant transformation of an ovarian dermoid cysts is very rare, with an incidence of approximately 1-2% of all ovarian dermoids. The more common scenario is the malignant transformation of certain elements (most commonly squamous components) of highly specialized or solid dermoids. The most common malignancy in both ovarian dermoid cysts and other types of teratomas is squamous cell carcinoma. If malignant transformation does occur, the prognosis is poor.
Ultrasound appearances are often characteristic because of the presence of a highly echogenic dermoid plug (Rokitansky nodule), which is the solid element within the cyst that contains hair follicles, sebaceous glands, fat, and calcified elements. Fluid-fluid levels can also be seen. Ovarian dermoids are the most commonly missed ovarian neoplasms on sonography, often due to the "tip of the iceberg" sign, in which the back wall of the cyst is obscured by acoustic shadowing. As a result, the echogenic Rokitansky nodule may be misinterpreted as bowel gas. Differential diagnosis on ultrasound includes tubo-ovarian abscesses, which can also contain fluid-fluid levels and echogenic pus that can produce acoustic shadowing caused by gas formation. Ectopic pregnancies also demonstrate shadowing from bone and contain echogenic hemorrhage. Other conditions in the differential diagnosis include other benign or malignant ovarian neoplasms, endometriomas, pedunculated uterine fibroids, hydrosalpinges, pelvic kidneys, and peritoneal cysts.
The diagnosis of ovarian dermoid cysts using computed tomography (CT) and magnetic resonance imaging (MRI) is fairly straightforward, as these imaging modalities are better able to identify and distinguish the multiple specific densities within the masses. On a CT scan, fat attenuation within a cyst, with or without calcification in the wall, is diagnostic for ovarian dermoid cysts. A floating mass of hair can also sometimes be identified at the fat–fluid interface. Using MRI, the sebaceous component of dermoid cysts can be identified with very high signal intensity on T1-weighted images. The signal intensity of the sebaceous component on T2-weighted images is variable, usually approximating that of fat. Chemical-shift artifacts in the frequency-encoding direction can also be used to detect fat and distinguish it from a hemorrhage.
As a result of the potential for complications, such as torsion and rupture, dermoids are usually resected when found. Gynecologic referral is recommended upon diagnosis, as was done for this patient. In most cases, a simple cystectomy is preferred, with many gynecologists choosing laparoscopy as an acceptable alternative to laparotomy in resection because of reductions in postoperative pain, blood loss, and length of hospital stay. Some studies have found an increased intraoperative spillage rate with laparoscopy, while others have not. There is a 4% risk of recurrence after resection.
To learn more about ovarian dermoid cysts, please visit the eMedicine articles Teratoma, Cystic and Ovarian Cysts in the Medicine, Ob/Gyn, Psychiatry, and Surgery section, and Dermoid Cyst in the Dermatology section.
References
Dahnert W. Radiology Review Manual. 3rd ed. Baltimore, Md: Williams & Wilkins; 1996: 743.
Outwater EK, Seigelman ES, Hunt JL. Ovarian teratomas: tumor types and imaging characteristics. RadioGraphics 2001 Mar-Apr; 21(2):475-90. [MEDLINE: 11259710]
Jeong YY, Outwater EK, Kang HK. Imaging evaluation of ovarian masses. Radiographics 2000 Sep-Oct; 20(5):1445-70. [MEDLINE 10992033]
