PMC5317072_01
Contrast enhanced computed tomography image of the abdomen: 5.5 cm x 4.4 cm sized well encapsulated inhomogeneous mass (arrow heads) with central areas of necrosis in the upper pole of right kidney
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F1
On evaluation, contrast enhanced computed tomography (CT) scan of abdomen showed 5.5 cm x 4.4 cm sized well-encapsulated mass in the upper pole of right kidney [Figure 1].
Microscopic examination of right nephrectomy specimen follicular cells suggesting metastatic deposits from thyroid malignancy or a rare primary renal tumor (thyroid like follicular carcinoma of the kidney) inset: Immunohistochemistry performed showed that the cells were strongly positive for pan-cytokeratin, thyroid transcription factor-1, thyroglobulin (as shown in figure), suggesting metastatic deposits from thyroid malignancy
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F2
Microscopic examination offered a differential diagnosis of metastatic deposits from thyroid malignancy or a primary thyroid-like follicular carcinoma of the kidney) [Figure 2]. Immunohistochemistry performed showed that the cells were strongly positive for pan-cytokeratin, thyroid transcription factor-1 and thyroglobulin [Figure 2], suggesting metastatic deposits from thyroid malignancy.
Ultrasound of neck revealed bilateral hypoechoic nodules with peripheral rim of egg-shell calcifications (left lobe nodule is shown)
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F3
Ultrasonography (USG) of the neck showed 2.1 cm x 1.7 cm x 1.5 cm (R) and 2 cm x 1.5 cm x 1.6 cm (L) hypoechoic nodules with peripheral eggshell calcification with interruptions [Figure 3].
Fluorodeoxyglucose positron emission tomography-computed tomography maximum intensity projection image shows a hypermetabolic lesion in the thyroid and left acetabular region. Transaxial fused 18F-fluorodeoxyglucose positron emission tomography-computed tomography image shows hypermetabolic calcified nodule (black arrow) in the left lobe of thyroid gland with maximum standardized uptake value of 12.6 (arrow) and hypermetabolic lytic lesion in left acetabulum with maximum standardized uptake value of 9.5 (arrow)
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F4
A positron emission tomography-CT (PET-CT) was performed after injection of 10 mCi of 18F-fluorodeoxyglucose (FDG). 18F-FDG PET-CT maximum intensity projection image showed a hypermetabolic lesion in the left thyroid region [Figure 4]. Intense uptake was noted in a calcified nodule in the left lobe measuring 1.8 cm x 1.6 cm with maximum standardized uptake value (SUVmax) of 12.6, suggestive of neoplastic etiology [Figure 4]. Hypermetabolic lytic lesion with soft tissue component was seen in left anterior acetabular margin extending up to the left pubic bone with an SUVmax of 9.5 suggesting of skeletal metastasis [Figure 4].
Histopathology image of thyroidectomy specimen revealed features consistent with follicular variant of papillary thyroid carcinoma with vascular invasion
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F5
PTC with vascular invasion in the left lobe and nodule in the right lobe revealed encapsulated variant of PTC, with no vascular or tumour capsular invasion [Figure 5]. Postoperative iodine whole body scan (WBS) showed increased focal tracer uptake in the lytic lesion in the left acetabulum and no evidence of tracer uptake in the region of thyroid bed [Figure 6].
Postthyroidectomy iodine whole body scan image shows increased focal tracer uptake in the left acetabular region corresponding to the metastatic lytic lesion. No tracer uptake seen in the region of thyroid bed
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F6
PTC with vascular invasion in the left lobe and nodule in the right lobe revealed encapsulated variant of PTC, with no vascular or tumour capsular invasion [Figure 5]. Postoperative iodine whole body scan (WBS) showed increased focal tracer uptake in the lytic lesion in the left acetabulum and no evidence of tracer uptake in the region of thyroid bed [Figure 6].