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Pelvis » Female Pelvis (Gynecology)
Benign Cystic Teratoma ( Dermoid)
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Author(s) :
Rafay Ahmed, MD  |  Ross Wank, MD
 
Presentation A 30 year old female presented with lower abdominal pain and bilateral palpable masses in the pelvis.
 
 
 
Caption: Left Adnexa - Sagittal Transabdominal Scan
Description: Transabdominal scan shows a large complex, predominantly cystic mass. The left ovary could not be identified.
 
 
 
Caption: Left Adnexa - Transvaginal Scan
Description: Transvaginal scan shows multiple hyperechoic solid components within the mass.
 
 
 
Caption: Right Adnexa - Transvaginal Scan
Description: Transvaginal scan of the right adnexa demonstrates a complex predominantly echogenic mass. Some areas of the mass cause posterior enhancement while others cause shadowing. The mass is adjacent to a large myomatous ueterus.
 
 
 
Caption: Right Adnexa - Transvaginal Scan
Description: The mass exhibits posterior enhancement, low level echogenity of part of the content, focal areas of high echogenicity, some of which also cause shadowing. One area exhibits the clustered punctate high amplitude echo pattern typical created by "hair in fat".
 
Differential Diagnosis Follicular cysts
Dermoid (benign cystic teratoma)
Hemorrhagic cyst
Endometrioma
Abcess
Cystic Neoplasm ( benign or malignant)
Pyosalpinx or hydrosalpinx

 
Final Diagnosis Bilateral Ovarian Dermoids
 
Discussion

The ultrasound demonstrated bilateral adnexal multilobular predominantly cystic masses with multiple mural nodules of widely varying architecture and echogenicity.  Both lesions exhibited areas of posterior shadowing and areas of clustered punctate high amplitued echos characteristic of hair embedded in sebum, typical of the dermoid.

Cystic Teratomas or Dermoids account for 10% to 15% of all ovarian tumors and are bilateral in 10% of the cases. They are composed of mature epithelial elements: a combination of skin, hair, sebum, desquamated epithelium, and teeth.

Dermoids are relatively soft masses and on physical examination may be difficult to palpate and are frequently either missed or underestimated in size. If large, a dermoid may torse, and then present as acute abdominal pain. They are rarely malignant.

Dermoids range in size and echogenicity. Depending on the extent and admixture of their epithelial elements, the ultrasound patterns can vary markedly, even within a single mass. There are, however some typical patterns. The two “classic” dermoid appearances are the “tip of the iceberg” sign, caused by absorption of most of ultrasound beam at the top of the mass (because of multiple internal interfaces) and “dermoid plug” sign, which has the appearance of one or more hyperechoic areas within a hypoechoic mass.

 

Another less commonly seen , but more specific, dermoid appearance is identification of interlacing linear and punctuate echoes corresponding to crossing strands of hair within the mass.

 

Occasionally, a dense calcification corresponding to a completely formed or rudimentary tooth is seen and can be confirmed to be a tooth by a pelvic radiograph or a CT scan.

 

Rarely, a lipid-fluid level can be identified within the mass and the fluid level may shift position when the patient moves.

 

Very rarely, dermoids can be completely anechoic.  This pattern is encountered most commonly in adolescence.
 
Case References
  1. Middleton, W., Kurtz, A, Hertzberg, B. Ultrasound: The Requisites. 2nd ed. Philadelphia, Pennsylvania: Mosby, 2004. ISBN 0323017029
  2. SF Quinn, S Erickson, and WC Black. Cystic ovarian teratomas: the sonographic appearance of the dermoid plug. Radiology 1985 155: 477-478.
  3. A. W. Potter and C. A. Chandrasekhar. US and CT Evaluation of Acute Pelvic Pain of Gynecologic Origin in Nonpregnant Premenopausal Patients. RadioGraphics, October 1, 2008; 28(6): 1645 - 1659.
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  7. T.-T. Wu, H.-C. Wang, Y.-C. Chang, Y.-C. Lee, Y.-L. Chang, and P.-C. Yang. Mature Mediastinal Teratoma: Sonographic Imaging Patterns and Pathologic Correlation. J. Ultrasound Med., July 1, 2002; 21(7): 759 - 765.
  8. J. R. Rao, Z. Shah, V. Patwardhan, V. Hanchate, H. Thakkar, and A. Garg. Ovarian Cystic Teratoma: Determined Phenotypic Response of Keratocytes and Uncommon Intracystic Floating Balls Appearance on Sonography and Computed Tomography. J. Ultrasound Med., June 1, 2002; 21(6): 687 - 691.

 
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