Coexistence of malignant struma ovarii and cervical papillary thyroid carcinoma.
BACKGROUND
Struma ovarii is an uncommon monodermal teratoma in which thyroid tissue is the predominant element. Malignant transformation of struma ovarii is an even rarer occurrence.


METHODS
We describe a 42-year-old woman who underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy for a symptomatic left pelvic mass. Histology revealed malignant struma ovarii with classical papillary thyroid carcinoma expression. Ultrasonography of the cervical neck showed thyroid micronodules and a dominant 1-cm nodule in the left thyroid lobe. As the ovarian tumor was large, the patient underwent a total thyroidectomy with the intention of administering ¹³¹I therapy in an adjuvant setting. Histology of the cervical thyroid gland revealed bilateral multifocal papillary thyroid carcinoma with extrathyroidal extension and perithyroidal lymph node metastasis.


METHODS
Morphological (microscopy), immunohistochemical (Hector Battifora mesothelial cell 1, cytokeratin-19, galectin-3), and molecular (BRAF V600E, RAS, RET-PTC) characteristics and clonality analysis of the cervical thyroid and ovarian tumors were explored to distinguish them as separate malignancies.


RESULTS
The thyroid-type tumors from the cervical gland and ovary were discordant in terms of tissue histology and level of cytokeratin-19 expression. The clinical features and tumor profile results supported the independent existence of these two embryologically related, although topographically distinct, malignancies.


CONCLUSIONS
Our findings provided support for synchronous, albeit distinct, primary tumors in the ovary and cervical thyroid. "Field cancerization" and early genomic instability may explain multifocality in all thyroid-type tissue. In this regard, patients with malignant struma ovarii should undergo imaging of their thyroid gland for coexisting disease and thyroidectomy recommended for suspected malignancy or in preparation for radioiodine therapy.
MD, Division of Endocrinology and Metabolism, McGill University Health Centre, 687 Pine Avenue West, M9.05, Montreal, Canada QC H3A 1A1. aaron.leong@mail.mcgill.ca.
Aaron
A
Leong
Philip J R
PJ
Roche
Miltiadis
M
Paliouras
Louise
L
Rochon
Mark
M
Trifiro
Michael
M
Tamilia
D000328:Adult; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D053539:Keratin-19 / Q000378:metabolism; D008207:Lymphatic Metastasis; D009363:Neoplasm Proteins / Q000378:metabolism; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000378:metabolism / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D010051:Ovarian Neoplasms / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D018714:Radiotherapy, Adjuvant; D013330:Struma Ovarii / Q000378:metabolism / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D016606:Thyroid Nodule / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects / Q000528:radiation effects
D007457:Iodine Radioisotopes; D053539:Keratin-19; D009363:Neoplasm Proteins; D019275:Radiopharmaceuticals