PMC6190843_01
(A) Histological slides of primary PTC and lymph node metastasis. (A1) Primary PTC with well-formed papillary structures (20X, hematoxilyn/eosin); (A2) collateral diffuse lymphocytic thyroiditis with lymphoid follicles and germinal centers(5X, hematoxilyn/eosin); (A3) lymph node metastatic lesion of PTC (2.5X, hematoxilyn/eosin). (B) Fine-needle aspiration cytological smears of lung metastastic lesion. (B1) low power magnification showing papillary-like structures with smooth contours and palisading of nuclei (10X, papanicolau stain); (B2) high power magnification showing nuclear characteristics of PTC (finely granular chromatin and one pseudoinclusion) (40X, papanicolau stain); (B3) immunocytochemistry showing cytoplasmatic positivity for thyroglobulin, confirming the thyroid origin of the lung lesion (40X).
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F1
The histological diagnosis was papillary thyroid carcinoma (PTC), classical variant (Figure 1A1) but with focal areas of tall cells, perithyroid soft tissue invasion, and multifocality. Histology showed also the presence of a diffuse lymphocytic infiltration (Figure 1A2).A few central compartment lymph node metastases were also present (Figure 1A3) (pT3mN1aMx according to the 6th AJCC-TNM staging system). On November 2015 the largest lung nodule, that was located in the inferior left lobe, was subjected to fine needle biopsy and cytology confirmed that cell morphology was suggestive of PTC (Figures 1B1,2). Moreover, the immunohistochemistry was positive for TTF-1 and focally for Tg (Figure 1B3) and the measurement of Tg in the wash out of the needle used for the lung cytology was 1780 ng/ml, confirming the thyroid origin of the lesion.
(A)
18FDG-PET scan showing three hypermetabolic nodular lung lesions localized at the medial (1) (SUV max 3.1) and lateral (2) (SUV max 2.7) segment of the right medium lobe and at the apical segment (3) of the left inferior (SUV max 3.9) lobe of the lungs. (B) pWBS showing 131-I uptake corresponding to the hypermetabolic lung lesions localized at the medial segment of the right lobe and at the left inferior lobe.
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F2
August 2015 the patient was subjected to a computerized tomography (CT) scan that showed three small lesions (maximum diameter 12 mm) in the lung. A 18Fluorodeoxyglucose-Positron Emission Tomography (18FDG-PET) scan confirmed the presence of these lesions that were hypermetabolic (Figure 2A). The pWBS showed two areas of uptake in the lung that were suggestive of iodine avid lung metastases and likely corresponding to two of the lesions found at the CT and PET scan (Figure 2B).On May 2016 serum biomarkers, namely TgAb, continued to increase and the patient was subjected to a CT scan that showed a slight increase of the lung lesions (maximum diameter 14 mm). Taking into account the slow but continue increase of serum biomarkers on December 2016 the patient was treated with additional 150 mCi of 131-I.
Graphic representation of the patient's serum Tg values and TgAb titer between 2004 and 2018.
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F3
A detailed history of serum biomarkers (i.e., Tg and TgAb) variation is summarized and shown in Table 1 and Figure 3.