PMC7079252_01
HE and IHC of histopathology. Histopathology of biopsy of the breast. (a) and (b) show HE staining. Poorly differentiated malignant cells invading stromal areas. (c) shows an IHC positive for AE1/3, which rules out sarcoma. (d)-(f) show negative IHCs for GATA3, SOX100, and S100. These results exclude malignant melanoma.
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Histopathological examination showed a poorly differentiated carcinoma negative for ER, PgR, HER2, gross cystic disease fluid protein, and GATA-binding protein 3 (GATA3) (Figures 1(a)-1(c)). We excluded a diagnosis of malignant melanoma based on the following IHC findings: positive for pankeratin AE1/3 (Figure 1(d)) and negative for CK8, SOX10 (Figure 1(e)), S100 (Figure 1(f)), melan A, CD45, and desmin.
(a) CXR before dabrafenib and trametinib initiation. (b) 1 week after treatment. Arrow shows pleural effusion.
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Adverse Event ver. xx), which we controlled by withdrawing drug administration for a day. The swelling and pain in the right breast improved remarkably after the initiation of dabrafenib and trametinib. A chest X-ray at the 1-week follow-up showed the right pleural effusion had decreased in size (Figure 2(a)).
(a) Breast sections of CT scan before initiation of dabrafenib and trametinib. (b) Same section 2 weeks after treatment initiation. The arrow points to reduced mass and decreased pleural effusion.
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There was a general improvement in conditions, and we discharged the patient (Figure 3).
(a) CT scan section showing right axillary lymph nodes before treatment. (b) CT scan section showing right axillary lymph nodes 6 weeks after treatment initiation. Arrow shows right axillary lymph nodes being decreased after treatment.
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After 6 weeks of treatment, a CT scan showed further reduction in the size of the tumors in the right breast, axillary lymph nodes, and pleura (Figure 4).