eMedicine Specialties > Obstetrics and Gynecology > General Gynecology

Struma Ovarii: Differential Diagnoses & Workup

Author: Jing (Jeannie) R Chen, MD, Resident Physician, Department of Obstetrics and Gynecology, Tufts Medical Center
Coauthor(s): Sarah H Hughes, MD,, Staff Physician, Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Tufts Medical Center; David Chelmow, MD, Professor of Obstetrics and Gynecology, Tufts University School of Medicine; Program Director, Tufts University Affiliated Hospitals Obstetrics/Gynecology Residency Program; Chair, Tufts University Health Sciences Campus Institutional Review Board; Vice Chair for Research and Education, Department of Obstetrics/Gynecology, Tufts Medical Center
Contributor Information and Disclosures

Updated: Mar 16, 2010

Differential Diagnoses

All other forms of ovarian neoplasms, both benign and malignant
Hyperthyroidism
Ectopic Pregnancy
Metastatic thyroid cancer to the ovary
Endometrioma
Physiological ovarian cyst
Hydrosalpinx
Tubo-ovarian abscess

Workup

Laboratory Studies

  • CBC count
  • Blood type and screen
  • Cancer antigen 125
    • Nonspecific marker elevated in a variety of benign clinical settings, including menstruation, pregnancy, endometriosis
    • Elevated in epithelial ovarian, endometrial, bowel, breast, and lung cancer
    • Elevated in only 8 cases reported in the literature in the setting of struma ovarii6
  • Thyroid function tests are ordered only in patients with symptomatic hyperthyroidism.

Imaging Studies

  • Triple-contrast CT scan of the abdomen and pelvis should be performed to evaluate the extent of disease and the involvement of lymph nodes and other adjacent structures (eg, bowel). Typically, struma ovarii appear as a multicystic mass with no or moderate cystic wall enhancement.7
  • If a triple-contrast CT scan is not available and bowel involvement is suspected, sigmoidoscopy or colonoscopy should be performed.
  • Pelvic sonography is optional if a CT scan has already been performed. Frequently, this is an initial study.
  • Mammography should be performed in patients with pelvic masses of unknown origin.
  • Chest radiographs should be obtained in indicated patients.
  • In select cases, preoperative evaluation with uptake of sodium iodide I-123 has been performed to demonstrate thyroid uptake in pelvic masses.


Other Tests

  • Papanicolaou test
  • Iodine-131 scanning (In patients with suspected struma, this will evaluate active thyroid tissue in the pelvis or abdomen.)
  • Thoracentesis in patients with pleural effusion (Cytology may reveal adenocarcinoma in the pattern of malignant thyroid cells.)


Histologic Findings

On gross examination, the struma is brown or green-brown and solid, but it can also be partly or entirely cystic, filled with gelatinous fluid. The struma is rarely bilateral. Most strumal tissue is not functionally active, and cases associated with thyrotoxicosis can be due to autoimmune stimulation of the normal thyroid gland.

Pathological examination reveals thyroid tissue as the major component of the mass, and is most commonly found in a teratoma. Thyroid tissue may be papillary, follicular, or mixed pattern, and it can include elements of mucinous cystadenocarcinoma, Brenner tumor, carcinoid, or melanoma. Birefringent crystals of calcium monohydrate are present in most patients, which is considered specific for tumors of thyroid origin. Immunohistochemical staining for thyroglobulin, triiodothyronine (T3), and thyroxine (T4) can confirm the diagnosis.

Malignancy is defined by histological features of the tumor including cellular atypia and hyperplasia, nuclear pleomorphism, mitotic activity, and invasion into surrounding vessels or the ovarian capsule. Currently, the pathological criteria used in diagnosing thyroid carcinoma are widely accepted as the standard in diagnosing malignant struma ovarii.4 However, there is still controversy over the defining characteristics of a malignant struma ovarii tumor.

Malignant struma ovarii is divided into 3 different categories by histology. 

  • Papillary type is the most common and identified by “ground glass” or overlapping nuclei
  • The follicular variant of papillary carcinoma shares the same nuclear characteristics as the papillary type but has a follicular architecture.
  • Follicular carcinoma is identified by follicles of mitosis around vascular and capsular structures.8

More on Struma Ovarii

Overview: Struma Ovarii
Differential Diagnoses & Workup: Struma Ovarii
Treatment & Medication: Struma Ovarii
Follow-up: Struma Ovarii
References
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References

  1. Utsunomiya D, Shiraishi S, Kawanaka K. Struma ovarii coexisting with mucinous cystadenoma detected by radioactive iodine. Clin Nucl Med. 2003;28(9):725-7. [Medline]. [Full Text].

  2. Yoo SC, Chang KH, Lyu MO, Chang SJ, Ryu HS, Kim HS. Clinical characteristics of struma ovarii. J Gynecol Oncol. Jun 2008;19(2):135-8. [Medline].

  3. Roth LM, Talerman A. The enigma of struma ovarii. Pathology. Feb 2007;39(1):139-46. [Medline].

  4. Bal A, Mohan H, Singh SB, Sehgal A. Malignant transformation in mature cystic teratoma of the ovary: report of five cases and review of the literature. Arch Gynecol Obstet. Mar 2007;275(3):179-82. [Medline].

  5. Kim D, Cho HC, Park JW, Lee WA, Kim YM, Chung PS. Struma ovarii and peritoneal strumosis with thyrotoxicosis. Thyroid. Mar 2009;19(3):305-8. [Medline].

  6. Mui MP, Tam KF, Tam FK, Ngan HY. Coexistence of struma ovarii with marked ascites and elevated CA-125 levels: case report and literature review. Arch Gynecol Obstet. May 2009;279(5):753-7. [Medline].

  7. Jung SI, Kim YJ, Lee MW, Jeon HJ, Choi JS, Moon MH. Struma ovarii: CT findings. Abdom Imaging. Nov-Dec 2008;33(6):740-3. [Medline].

  8. Makani S, Kim W, Gaba AR. Struma Ovarii with a focus of papillary thyroid cancer: a case report and review of the literature. Gynecol Oncol. Sep 2004;94(3):835-9. [Medline].

  9. DeSimone CP, Lele SM, Modesitt SC. Malignant struma ovarii: a case report and analysis of cases reported in the literature with focus on survival and I131 therapy. Gynecol Oncol. Jun 2003;89(3):543-8. [Medline].

  10. Robboy SJ, Shaco-Levy R, Peng RY, Snyder MJ, Donahue J, Bentley RC. Malignant struma ovarii: an analysis of 88 cases, including 27 with extraovarian spread. Int J Gynecol Pathol. Sep 2009;28(5):405-22. [Medline].

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Further Reading

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Keywords

teratomatous ovarian tumor, hyperthyroidism, cystadenomas, strumosis, teratoma, pelvic mass, oophorectomy, total hysterectomy, bilateral salpingo-oophorectomy, thyroidectomy

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Contributor Information and Disclosures

Author

Jing (Jeannie) R Chen, MD, Resident Physician, Department of Obstetrics and Gynecology, Tufts Medical Center
Disclosure: Nothing to disclose.

Coauthor(s)

Sarah H Hughes, MD,, Staff Physician, Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Tufts Medical Center
Sarah H Hughes, MD, is a member of the following medical societies: Society of Gynecologist Oncologists
Disclosure: Nothing to disclose.

David Chelmow, MD, Professor of Obstetrics and Gynecology, Tufts University School of Medicine; Program Director, Tufts University Affiliated Hospitals Obstetrics/Gynecology Residency Program; Chair, Tufts University Health Sciences Campus Institutional Review Board; Vice Chair for Research and Education, Department of Obstetrics/Gynecology, Tufts Medical Center
David Chelmow, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Medical Association, Association of Professors of Gynecology and Obstetrics, Massachusetts Medical Society, Phi Beta Kappa, Sigma Xi, Society for Gynecologic Investigation, and Society for Medical Decision Making
Disclosure: Nothing to disclose.

Medical Editor

Jordan G Pritzker, MD, MBA, FACOG, Assistant Professor of Obstetrics, Gynecology, and Women's Health, Women's Comprehensive Health Center, Albert Einstein College of Medicine; Physician-In-Charge, Department of Obstetrics and Gynecology, Long Island Jewish Medical Center
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

A David Barnes, MD, PhD, MPH, FACOG, Consulting Staff, Department of Obstetrics and Gynecology, Mammoth Hospital (Mammoth Lakes, California), Pioneer Valley Hospital (Salt Lake City, Utah), Warren General Hospital (Warren, Pennsylvania), and Mountain West Hospital (Tooele, Utah)
A David Barnes, MD, PhD, MPH, FACOG is a member of the following medical societies: American College of Forensic Examiners, American College of Obstetricians and Gynecologists, American Medical Association, Association of Military Surgeons of the US, and Utah Medical Association
Disclosure: Nothing to disclose.

CME Editor

Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Hancock Medical Center
Frederick B Gaupp, MD is a member of the following medical societies: American Academy of Family Physicians
Disclosure: Nothing to disclose.

Chief Editor

Michel E Rivlin, MD, Professor, Coordinator of Quality Assurance/Quality Improvement, Department of Obstetrics and Gynecology, University of Mississippi School of Medicine
Michel E Rivlin, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Medical Association, Mississippi State Medical Association, and Royal College of Surgeons of Edinburgh
Disclosure: Nothing to disclose.

 
 
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