High-grade PIN : Cribriform type
Cribriform high-grade PIN consists of large glandular units with punched out lumina. The acinar cells form Roman bridges that criss-cross the lumen. The nuclei show enlargement and hyperchromasia with prominent nucleoli. With basal cell markers, a fragmented basal cell layer is usually seen. The differential diagnosis includes cribriform carcinoma, ductal carcinoma, and basal cell hyperplasia with prominent nucleoli.