The patient was a 62-year-old Chinese woman who went to see a doctor on July 13, 2020, because she had had an axillary mass for 6 months. Her past medical history was unremarkable. Physical examination revealed that a mass of about 4 cm × 4 cm could be palpated on the deep surface of the right armpit. It was hard, had a distinct boundary, and could be pushed without tenderness. The surrounding lymph nodes were not swollen. After admission, the patient underwent complete relevant auxiliary examinations. Ultrasonography of the breast and lymph nodes in drainage areas as well as mammography showed that both mammary glands were Breast Imaging-Reporting and Data System for Ultrasound (US-BI-RADS) 1, and the right axillary lymph node was enlarged. A plain scan of the breast by magnetic resonance imaging along with enhanced angiography found an abnormal signal shadow in the right armpit suggesting a tumor, possibly neurogenic. Enlarged lymph nodes were also noted, suggesting the presence of infection. Further investigation was clearly required. Fine needle aspiration cytology (FNAC) showed that it was considered as small round cell malignant tumor. The right axillary mass was further examined by thick needle aspiration. The pathological biopsy results showed that small cell tumors, combined with the immunophenotype, considered mesenchymal tumors, tended to one-way synovial sarcoma.
The patient was told about the need for surgical treatment as well as the risk of refusing it; with her consent, surgery was then planned. Under general anesthesia, she underwent radical resection of the right axillary lymph node on August 5, 2020. Postoperative pathology combined with morphologic and immunohistochemical examination identified a malignant soft tissue tumor conforming to a poorly differentiated synovial sarcoma. Twenty-eight lymph nodes were detected and no tumor metastasis was found in any (0/28). Immunohistochemistry was as follows: HMB45 (-), Melan-A (-), S-100 scattered (+), Desmin (-), Bcatenin membrane (+), P53 wild type (+), P16 (-), CK (-), CD56 (-), Myogenin (-), CD10 (-), CyclinD1 (+), INI-1 (+), TLE1 (+), NKX2.2 (-), BCL-2 (+), CD34 (-). After the pathologic specimen was re-examined under consultation, a spindle cell soft tissue sarcoma of the right armpit was identified and verified by SYT fusion gene test results, making this case consistent with fibrosarcoma. After the contraindication was eliminated, the patient received six cycles of AI (adriamycin plus ifosfamide) chemotherapy.
About a year after the end of chemotherapy, on March 17, 2022, the patient visited our hospital with the recurrence of an axillary mass with chest wall and breast skin metastasis (Fig. 1A). FNAC of the right chest wall mass suggests a small round cell malignancy with obvious nucleolus (Fig. 1B). The mass in the right chest wall was excised under local infiltration anesthesia. Histopathologic analysis was performed by two skilled pathologists, and postoperative pathology identified a malignant soft tissue tumor. Gene detection and immunohistochemistry were consistent with MM metastasis. Figure 2 shows hematoxylin and eosin (H&E) staining and IHC staining of tissues from the mass in the chest wall. The infiltrating growth of tumor cells is mainly round cells. The cells are obviously heterotypic, have abundant eosinophilic cytoplasm, and are easy to see nucleolus and mitosis. IHC staining results were as follows: SOX10 (+), S-100 (+), HMB-45 (+), Ki-67 (+, 70%), CD34 (-), CD99 (-), TLE1 (-), EMA (-), Vim (+), p53 (+, 1%), CK (-), Desmin (-), MelanA (+), SOX10 (+). With the consent of the patient, we performed Braf gene mutation detection on the tissue from the chest wall, verifying a type of Braf gene mutation(Fig. 3). Based on the patient's gene test results, oncologists suggested that double-target combination therapy (dallafenil combined with trimetinib) should be carried out according to the guidelines, including or excluding chemotherapy. After two courses of targeted therapy, the MM metastasis disappeared. We plan to evaluate the long-term therapeutic and side effects over time.