Fig. 2.

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)