45-year-old woman with bleeding plantar papule   

Findings and diagnosis


Microscopic exam showed an epithelial neoplasm consisting of uniform aggregates of monomorphous basaloid and squamous epithelial cells emanating from the epidermis, some of which were surrounded by ductlike structures. 

Differential diagnosis

  • Porocarcinoma
  • Basal cell carcinoma
  • Hidradenoma
  • Poroma
  • Clonal seborrheic keratosis
  • Poroid hidradenoma
  • Squamous cell carcinoma
  • Eccrine syringofibroadenoma

Diagnosis: Poroma