HER2-positive Stage IIB breast cancer complicated by acute neuro-Behcet disease during neoadjuvant treatment

What happened, in summary

This 40-year-old woman had Behcet disease that had been well controlled with colchicine since age 32. She noticed a left breast mass for about 8 months before seeing a breast surgeon. Mammography and ultrasound showed a 2.4 cm left breast tumor with swollen left axillary lymph nodes, and PET-CT showed uptake in both the breast mass and axillary node, without distant metastasis. Core biopsy confirmed invasive ductal carcinoma. Biomarker testing showed ER-positive, PR-positive, HER2-positive disease with HER2 amplification by FISH and a Ki-67 index of 50%. The cancer was staged cT2N1M0, Stage IIB. She started neoadjuvant TCbHP chemotherapy: docetaxel, carboplatin, trastuzumab, and pertuzumab. After 1 course, she developed grade 2 stomatitis, fatigue, and appetite loss. After 4 courses, symptoms worsened and new neurologic problems appeared, including headache, fever, recurrent oral ulcers, facial redness, dysarthria, altered consciousness, and left-sided weakness. MRI showed bilateral basal ganglia abnormalities, and cerebrospinal fluid testing supported acute neuro-Behcet disease. She received steroid pulse therapy with SoluMedrol 1000 mg/day for 3 days, followed by a taper. Her communication and walking gradually improved, and brain MRI 2 weeks and 3 months after treatment showed improvement of the basal ganglia abnormalities and reduced ventricular compression. Perioperative prednisolone was used to reduce the risk of neurologic flare. One month after discharge, she underwent left partial mastectomy and axillary lymph node dissection. Pathology showed residual invasive cancer, no metastasis in 8 resected nodes, and a Grade 2b treatment effect. She then received trastuzumab, pertuzumab, and tamoxifen for 8 months. As of June 2024, 2 years after surgery, neither breast cancer nor neuro-Behcet disease had recurred.