Thyrotoxic adenoma followed by atypical hyperthyroidism due to struma ovarii: clinical and genetic studies.
OBJECTIVE
Atypical forms of hyperthyroidism represent a diagnostic challenge for clinicians. Struma ovarii is an ovarian teratoma and constitutes a rare cause of ectopic thyroidal hormonal production. We describe a case of struma ovarii that combined two different sources of hyperthyroidism in the same patient and report genetic studies in order to contribute a better understanding of the autonomy and tumorigenesis of the struma ovarii.


METHODS
A 73-year-old nulliparous woman presented a thyroid toxic adenoma that was successfully treated with 10 mCi radioiodine. Unexpectedly, a new onset of hyperthyroidism prompted us to look for a second etiology. A whole-body scan with (123)I detected a pelvic hyperfixation suggesting struma ovarii, and a thyroid differentiated left ovarian teratoma 3 cm in size was surgically removed. We screened for mutations of thyroid-stimulating hormone receptor and Gs-alpha protein genes, as these mutations are common in thyroid adenomas. We did not identify any mutations. Androgen receptor study demonstrated a monoclonal status. Comparative genomic hybridization did not reveal any chromosomal abnormality. However, loss of heterozygosity analysis showed several structural abnormalities, compared with the majority of benign ovarian teratomas, which show a normal karyotype.


CONCLUSIONS
This is the first well-documented report of thyrotoxic struma ovarii revealed after treatment of a single thyroid toxic adenoma. We have shown in this case that struma ovarii originates from a single germ cell, and, albeit benign, this tumor presents several chromosomal abnormalities. Struma ovarii-induced hyperthyroidism is likely to be mediated by mechanisms different from those of the classical thyroid toxic adenoma.
Ciccarelli
Antonio
A
Department of Endocrinology, Liège University, Liege, Belgium.
Valdes-Socin
Hernan
H
Parma
Jasmine
J
Khoo
Sok Kean
SK
Schoumans
Jacqueline
J
Colao
Annamaria
A
Hamoir
Etienne
E
Beckers
Albert
A
D000236:Adenoma / Q000150:complications* / Q000235:genetics / Q000532:radiotherapy; D000368:Aged; D005260:Female; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000235:genetics; D006801:Humans; D006980:Hyperthyroidism / Q000000981:diagnostic imaging / Q000209:etiology / Q000235:genetics; D019656:Loss of Heterozygosity; D009378:Neoplasms, Multiple Primary / Q000235:genetics / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000150:complications* / Q000235:genetics / Q000473:pathology; D011877:Radionuclide Imaging; D011989:Receptors, Thyrotropin / Q000235:genetics; D013330:Struma Ovarii / Q000150:complications* / Q000235:genetics / Q000473:pathology; D013964:Thyroid Neoplasms / Q000150:complications* / Q000235:genetics / Q000532:radiotherapy; D013971:Thyrotoxicosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000235:genetics
D011989:Receptors, Thyrotropin; D019205:GTP-Binding Protein alpha Subunits, Gs