PMC6006564_01
Histologic sections of malignant struma ovarii. Areas of adenomatous differentiation (a - lower right) and classic papillary thyroid carcinoma (a - center left) with papillary growth and cleared out "orphan Annie" nuclei. Area of Hurthle cell differentiation (a - center right) with an illustrative mitosis (a - inset). Tumor proliferation impinging on vascular structures (b). While the irregular border of the tumor and myxoid degeneration of the vessel wall are suggestive of infiltrative growth, no definitive vascular invasion is identified in the histologic sections reviewed. Tumor proliferation extends into the ovarian capsule (arrows) without extra-capsular extension (c). Struma ovarii (d - upper left) and squamous differentiation of the mature cystic teratoma (d - mid-lower right). Immunohistochemical stain for thyroid transcription factor (TTF-1) at 40x magnification with positive staining only in the areas of thyroid differentiation (e). a-d are hematoxylin and eosin stained with magnification 200x (a), 100x (b), and 40x (c, d)
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Fig1
Histologic sections demonstrated a struma ovarii with over 50% characterized by the classic features of a well-differentiated papillary thyroid carcinoma (Fig. 1A). The periphery of the tumor impinged on the ovarian capsule and vascular structures; however, no definitive evidence of invasion was seen on the histologic sections reviewed (Fig. 1B-C). Typical histology for an ovarian mature cystic teratoma (such as areas of squamous differentiation) were present in other areas of the tumor (Fig. 1D). The tumor expressed positive immunohistochemical staining for thyroglobulin (Tg) and thyroid transcription factor 1 (TTF1, Fig. 1E), but was negative for BRAF V600E.
Nuclear medicine imaging at initial evaluation and subsequent follow-up of metastatic struma ovarii. Diagnostic 131-I planar scan, posterior view (a) demonstrates central neck activity and abnormal activity in the left hemithorax, central pelvis and bilateral proximal femurs. Diagnostic SPECT/CT demonstrates thyroid remnant tissue in the thyroidectomy bed (b) and skeletal metastatic disease localized to left 9th rib (c), sacrum (d) and bilateral proximal femurs (e, f). Post-therapy 131-I planar scan, posterior view (g) demonstrates diffuse lung activity consistent with miliary pulmonary metastases in addition to focal central neck activity and skeletal metastatic foci. Follow-up diagnostic planar 131-I scan, posterior view (h) demonstrates physiologic radiotracer activity in the stomach, and urinary activity in the right renal collecting system and bladder, without foci of abnormal activity. Post-therapy 131-I scan, posterior view (i) obtained after 100 mCi therapeutic challenge ascertained resolution of pulmonary miliary metastatic disease, but residual foci of activity were demonstrated in the left hemithorax and pelvis and confirmed on SPECT/CT in the left ninth rib (k), sacrum (l), and left proximal femur (n) consistent with a partial therapeutic response in the skeleton. Focal sclerosis without focal 131-I uptake is demonstrated in the right femoral neck, consistent with treatment response and bone healing (m). Complete therapeutic response is demonstrated in the thyroidectomy bed (j)
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Fig2
A concurrent diagnostic I-131 scan (1 mCi) with planar and SPECT/CT imaging revealed focal central neck activity consistent with thyroid remnant and the presence of iodine-avid skeletal metastatic disease involving the left ninth rib, bilateral proximal femurs, and sacrum (Fig. 2A-F). Following 320 mCi I-131 therapy based on blood dosimetry calculations, post-therapy scan revealed the additional finding of miliary pulmonary metastases (Fig. 2G). The post-therapy I-131 scan demonstrated complete resolution of pulmonary metastatic disease; however, faint residual foci of activity were demonstrated in the left ninth rib, sacrum, and left proximal femur, consistent with a partial therapeutic response in the skeleton (Fig. 2I-N).