Tamoxifen-induced eccrine squamous syringometaplasia

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Tamoxifen is a common endocrine therapy for breast cancer.
• Cutaneous adverse drug reactions are known side effects of various medications, including chemotherapeutics.
• Eccrine squamous syringometaplasia (ESS) is a rare skin condition associated with diverse underlying pathologies.

Observation:

• A 74-year-old woman developed a papuloplaque eruption on her face, trunk, and limbs four weeks after initiating tamoxifen therapy for breast cancer.
• Skin biopsy revealed perivascular and periadnexal inflammation with squamous epithelial islands associated with eccrine epithelium.
• Immunohistochemistry confirmed squamous metaplasia and eccrine differentiation.

Findings:

• The patient was diagnosed with eccrine squamous syringometaplasia.
• The cutaneous eruption was clinically and pathologically correlated with tamoxifen use.
• Discontinuation of tamoxifen led to the resolution of the skin eruption.

Implications:

• This case represents the first reported instance of tamoxifen-induced eccrine squamous syringometaplasia.
• The findings expand the spectrum of known adverse cutaneous reactions to tamoxifen.
• This highlights the importance of considering drug-induced ESS in patients on tamoxifen presenting with specific dermatological symptoms.