PMC9575947_01
(A) The timeline of the whole management course of the patient with occult breast cancer. (B) One-year follow-up US features with thyroid metastases from her occult breast cancer (arrows show the metastasis areas which manifested as diffuse faveolate changes in the US).
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Cerebellar metastasis was diagnosed during the chemotherapy treatment ( Figure 1A ). Taxol liposome 210 mg d1 + Herceptin 318 mg d1 and four cycles of Herceptin 318 mg per 3 weeks as we monitored the progress in the thyroid. The sizes and hypoechoic areas of the thyroid gland changed repeatedly during this process ( Figure 1B ). The size of the diffuse faveolate area of the thyroid was obviously shrunk as shown in the final US examination.
(A) Cytology smear of the thyroid faveolate echo area in the US (Wright-Giemsa x1,000). (B) Histochemical staining of the biopsy specimen from thyroid (hematoxylin-eosin stain x400).
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The cytology showed a mass of tumor cells found in the smear ( Figure 2A ). Figure 2B ). Further, negative immunohistochemistry (IHC) results of thyroid transcription factor 1 (TTF1), TPO, and TG showed that the tumor cells were not derived from the thyroid ( Figure 3 ).
Immunohistochemical staining of the biopsy specimen from the thyroid (x400). TTF1-; TPO-; TG-; GATA-3-.
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Figure 2B ). Further, negative immunohistochemistry (IHC) results of thyroid transcription factor 1 (TTF1), TPO, and TG showed that the tumor cells were not derived from the thyroid ( Figure 3 ).
Immunohistochemical staining of the biopsy specimen from the thyroid (x400). Ki-67+ (60%); GCDFP15+; mammaglobin+; CD34+; P53+; E-cadherin+; HER2+; ER-; PR-.
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The positive staining of GATA3, gross cystic disease fluid protein 15 (GCDFP15), mammaglobin, CD34, P53, and E-cadherin confirmed that these neoplasms were infiltrating ductal carcinoma derived from the breast ( Figure 4 ). The molecular subtype of our OBC case turned out to be human epidermal growth factor receptor 2 (HER2) positive due to the positive IHC result for HER2, negative estrogen receptor (ER), and negative progesterone receptor (PR) ( Figure 4 ).