Black/brown hairy tongue is generally diagnosed clinically, but if a biopsy were indicated for an atypical presentation, what type of biopsy would be most appropriate?

Hairy tongue is typically a clinical diagnosis (elongated filiform papillae with surface staining/discoloration from bacteria, food, tobacco, or certain medications) not usually requiring biopsy. If biopsy were indicated for an atypical or diagnostically uncertain presentation, an incisional biopsy of a representative area would be more appropriate than excisional biopsy, since the condition is diffuse across the dorsal tongue surface rather than a single, discrete, fully excisable lesion.