Pilomatrixoma : Immunohistochemistry
Pilomatrixoma is positive for cyclins D1, D2, and D3 as well as beta-catenin (nuclear staining) in basaloid/matrix cells. Maturing areas show only cytoplasmic and membrane staining for beta-catenin. Ghost cells are negative for beta-catenin. Dystrophic calcification (in the form of basophilic stippling as seen here) is present in the vast majority of cases. Calcification is sometimes extensive. About 20% of cases show ossification and may even have foci of extramedullary hematopoiesis.