Mature cystic teratoma with high proportion of solid thyroid tissue: a controversial case with unusual imaging findings

Abstract

We describe a case of a mature cystic teratoma of the ovary with high proportion of solid thyroid tissue (< 50% of the entire tumor) in a childbearing woman. The patient presented with non-specific abdominal bloating. Pelvic ultrasound and magnetic resonance imaging revealed a complex cystic-solid tumor confined to the left ovary with an anterior fat-containing locus compatible with mature cystic teratoma and a posterior predominantly solid component with low signal intensity on T2-weighted images that was histopatologically diagnosed as benign thyroid tissue. Thyroglobulin levels were in normal range. Although thyroid tissue is present in up to 20% of mature cystic teratomas, with exception of struma ovarii, it is not usually macroscopically nor radiologically identified. The differential diagnosis should include T2-hypointense adnexal lesions associated with mature cystic teratoma, malignant transformation of mature teratoma, and immature teratoma.

Recurrent Struma Ovarii Presented with High Levels of Thyroglobulin

“…Low T1 and T2 signal shows simple cysts, whereas intermediate T1 and low T2 signal demonstrates colloid-filled follicles, resembling thyroid microscopic appearance [ 1 , 8 ]. Fat suppression techniques are used in MRI to evaluate the fat component of the tumor [ 9 ].…”

Management of Metastatic Struma Ovarii with Papillary Thyroid Carcinoma and a Neuroendocrine Component: A Case Report

“…Malignant struma ovarii is a rare tumor which does not often metastasize. 1,3 Histological differentiation of benign from malignant struma ovarii has been proven both difficult and of limited clinical value. Previous reports have shown that a proportion of histologically benign tumors will behave in a malignant fashion and that the majority of malignant tumors will not progress after local resection.…”

“…A Case Report 1 Karim Jamal, 2 Mechteld C de Jong, 3 Ian Proctor, 4 Simon Morley, 5 Suganya Sivabalasingham, 6 Tarek E Abdel-Aziz, 7 liver lesions to be iodine-avid and therefore presumed metastasis.…”

“…Struma ovarii is an uncommon entity, accounting for 1% of all teratomas, and it is usually benign. [1][2][3] While small elements of thyroid tissue are found in up to 15% of all germ-cell tumors, to diagnose strumaovarii, thyroid tissue needs to compromise at least 50% of the tumor volume. 4 Malignant transformation of these lesions occurs in less than 5% of cases, and distant metastatic disease is even rarer.…”

Malignant Transformation in Mature Cystic Teratomas of the Ovary: Case Reports and Review of the Literature

“…The diameter of a squamous cell carcinoma arising in an ovarian MCT ranges from 9.7-15.6 cm (1, 4-8, 16, 17) and median age of patients is approximately 55 years (1,16), whereas the size of thyroid carcinoma in an MCT ranges from 5 to 20 cm and the median age of patients is about 42-45 years (12,15). The preoperative detection of malignant transformation is very difficult and the diagnostic accuracy of ultrasound, magnetic resonance imaging and computed tomography (CT) is uncertain (18)(19)(20)(21)(22)(23). Malignancy is usually diagnosed post-operatively based on histopathologic findings (6,8,13,15,24).…”