Collagenous Spherulosis

Supplemental Studies

Myoepithelial cells present around periphery and surrounding spherules
- Keratin positive
- S100, actin, calponin, p63 positive, smooth muscle myosin
Remainder of lesional cells are epithelial cells
- Keratin positive
- S100, actin, calponin, p63, CD117 negative
Spherules are positive for type IV collagen

Spherules:
- PAS and Alcian Blue variable
  - May stain with both or either
- Trichrome: stain blue
- Mucicarmine positive (reported in cases with basophilic spherules)