Patterns of skin and soft tissue metastases from breast cancer according to subtypes: Relationship between egfr overexpression and skin manifestations

Objectives: We evaluated whether skin changes and soft tissue infiltration patterns reflect breast cancer subtypes based on the breast hormonal receptor (HR) and human epidermal growth factor receptor 2 (HER2) status at the time of skin metastasis. Methods: We retrospectively reviewed the patients' medical records with radiologic imaging studies. Results: The numbers of patients of each subtype were as follows: HR positive (HR+ve) 53 (42.4%), HER2 enriched 43 (34.4%), and triple negative (TN) 29 (23.2%). The presence of skin ulceration was found more commonly in the HR+ve group than in the others (57.1% for HR+ve vs. 25% for HER2 enriched vs. 15.4% for TN, p = 0.019). Erythematous infiltrations were shown predominantly in the TN group (19.0 vs. 54.2 vs. 84.6%, respectively, p < 0.000). On CT scans, soft tissue infiltration appeared to be more common in the HER2-enriched and TN groups than in the HR+ve group (24.5 vs. 41.9 vs. 48.3%, respectively, p = 0.013). Erythematous infiltrative lesions were more common in patients with epidermal growth factor receptor overexpression (p = 0.036). Conclusion: The patterns of skin involvement including surrounding soft tissue infiltration may reflect breast cancer subtype. Prospective evaluation is necessary to confirm their influential effect on breast cancer subtypes.