Radiation-Induced Eccrine Squamous Syringometaplasia With Perineural Invasion

Area of Science:

• Dermatopathology
• Surgical Pathology

Background:

• Eccrine squamous syringometaplasia (ESS) is a benign metaplastic response of eccrine ducts.
• ESS can histologically mimic squamous cell carcinoma (SCC), posing diagnostic challenges.

Observation:

• An 82-year-old man presented with a presumed SCC on radiation dermatitis, treated with Mohs surgery.
• During Mohs surgery, a squamous proliferation was identified as ESS.
• Perineural invasion was noted in the ESS, a feature not previously reported.

Findings:

• The case demonstrates ESS presenting with perineural invasion, complicating the differentiation from SCC.
• Histologic features distinguishing ESS from SCC are crucial for accurate diagnosis.

Implications:

• Accurate differentiation of ESS from SCC is vital to avoid unnecessary surgical procedures.
• Recognition of perineural invasion in ESS expands its known clinicopathologic spectrum.
• This finding underscores the importance of careful histologic evaluation in challenging dermatologic cases.