Sections from the nodule show a pilar tumor composed of solid masses of basaloid and keratotic stratified squamous epithelium exhibiting abrupt keratinization thus forming some squamous eddies. Borders of the masses are rounded and the overall pattern of growth indicates an intracystic tumor lined by same type of cells. In some foci, the tumor pseudocapsule looks infiltrated by these masses of cells. In addition, in multiple foci (marker on the slides), cells become larger with large vesicular nuclei and active mitosis thus indicating focal malignant transformation in this proliferating pilar tumor.
Scalp lobulated mass.
Nodular mass measured 2x1.5x1 cm, partially covered by skin ellipse measured 1 cm, totally embedded. No evidence of surrounding tissue clearance.
Scalp mass, excision:
COMMENT:
No evidence of adequate surrounding tissue clearance. Wider excision of the lesion is advised to avoid local recurrence which is a great possibility.