Change of HER2 status during disease recurrence predicts good prognosis for primary squamous cell carcinoma of the breast: A case report.

RATIONALE

Primary squamous cell carcinoma (PSCC) of the breast is one of the least common types of breast cancer. Adjuvant treatment for PSCC remains an unresolved issue.

PATIENT CONCERNS

We reported a case of a 48-year-old postmenopausal female patients with a 2 × 2.5 cm lump presented with no symptoms.

DIAGNOSES

This patient was diagnosed as PSCC of the breast. The original tumor and first recurrence exhibited triple negative phenotype, whereas the second recurrence was HER2-positive.

INTERVENTIONS

A tumorectomy with latissimus dorsi flap reconstruction for the second recurrence was performed followed by targeted therapy with trastuzumab.

OUTCOMES

The patient had a complete remission, which was sustained over the 25 months of follow-up after the tumorectomy.

LESSONS

This is the first reported case in literature of a breast PSCC patient with switched immunohistochemical phenotypes during disease recurrence. Surgical resection with flap reconstruction and targeted therapy successfully treated the recurrence.