Hepatocellular Carcinoma - Pseudoglandular (Acinar) Pattern

The WHO describes several HCC histologic patterns: trabecular, acinar, solid, and scirrhous. Acinar (pseudoglandular, adenoid) pattern is less common than the trabecular pattern and is characterized by acini (gland-like spaces) lined by tumor cells, resembling cholangiocarcinoma. The acini are formed by dilatation of bile canalicular-like structures elaborated by the tumor and often contain bile or proteinaceous material. Acinar pattern HCC can be differentiated from cholangiocarcinoma by the following immunoprofile: HCC is MOC31-, hep par-1+, canalicular pCEA+, and usually CK19/CK20-; cholangiocarcinoma is MOC31+, hep par-1-ve, cytoplasmic/membranous pCEA+, and CK7+/CK19+.