Intra-adrenal bile ductules associated with adreno-hepatic fusion: a possible origin for adrenal epithelial cysts.

AIMS: To elucidate the relationship between the rare phenomenon of adrenal cysts and adreno-hepatic fusion (AHF)-related intra-adrenal bile ductules. METHODS AND RESULTS: We examined 673 right and 662 left postmortem adrenal glands. AHF was defined as an adhesion between the liver and an adrenal with closely intermingled parenchymal cells or partial absence of the capsule dividing the two organs. AHF was found in seven (1.0%) right adrenals. AHF-related intra-adrenal bile ductules were observed in four (0.6%) adrenals, and were accompanied by aberrant hepatocytes (two adrenals), microcystic changes (two adrenals) and, in one case, a 15-mm-sized cyst. The cyst-lining cells, which focally resembled the cells of the neighbouring intra-adrenal bile ductules, were positive for cytokeratin 7 (CK7), CK19 and epithelial membrane antigen, and negative for CK20, vimentin, CD34 and calretinin. Identical findings were made in bile ductules located within fused adrenals and livers. CD10 staining was weaker or absent in the microcystic or cystic bile ductules found within adrenals. CONCLUSIONS: The 15-mm cyst we describe may have been an adrenal epithelial cyst derived from AHF-related intra-adrenal bile ductules, a possible pathogenesis for the rare phenomenon of right adrenal epithelial cysts.