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. CASE REPORT: 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.
A Ciccarelli, H Valdes-Socin, J Parma, SK Khoo, J Schoumans, A Colao, E Hamoir and A Beckers
DC Luccio-Camelo, KN Une, RE Ferreira, SK Khoo, R Nickolov, MD Bronstein, M Vaisman, BT Teh, LA Frohman, BB Mendonca and MR Gadelha
We report here the genetic findings of a new isolated familial somatotropinoma (IFS) kindred in which the mother (subject I:2) and one daughter (subject II:2) are affected; their ages at diagnosis were 25 and 14 years respectively. Additionally, patient I:2 developed virilization due to an androgen-secreting adrenocortical mass, presenting clinical and molecular features of sporadic adrenal carcinoma. To genotype this family and to narrow down the candidate interval of the putative IFS gene at 11q13, we performed haplotyping on the DNA from all five members of the family and allelotyping of one available somatotropinoma using polymorphic microsatellite markers from chromosome region 11q12.1-11q13.5. Results indicated that the disease haplotype, between markers D11S956 and D11S527, was transmitted from subject I:2 only to subject II:2. A meiotic recombination event was detected in the fraternal twin sister of II:2 (subject II:1), but her disease status is unknown. Since she is only 18 years old this genetic event cannot yet narrow down the area involved in the pathogenesis of IFS. Allelotyping of the somatotropinoma from II:2 revealed loss of the chromosome carrying the wild-type copy of the putative IFS gene inherited from her father. These results support the involvement of a tumor suppressor gene at 11q13.1-q13.3 in the pathogenesis of IFS.