An analysis of five clear cell papillary cystadenomas of mesosalpinx and broad ligament: four associated with von Hippel‐Lindau disease and one aggressive sporadic type

Abstract

Clear cell papillary cystadenoma (CCPC) is associated with von Hippel-Lindau disease (VHLD), but rarely involves mesosalpinx and broad ligament (M/BL). This study provides new data about its behaviour and immunophenotype. We performed an analysis of four benign cases of CCPC of M/BL with either characteristic clinical features or genetic markers [loss of heterozygosity (LOH)] of VHLD in patients ranging from 24 to 36 years and a sporadic case in a 52-year-old presenting with peritoneal metastases. All CCPCs were papillary but had solid and tubular areas. Haemorrhage, thrombosis and scarring were constant features and related to an unusual pattern of sub-epithelial vascularity. All clear or oxyphilic cells co-expressed cytokeratin 7 (CK7), CAM5.2 and vimentin, with strong apical CD10 and nuclear paired box gene 2 (PAX2) immunoreactivity. Three cases also showed positivity for VHL40, epithelial membrane antigen (EMA), Wilms' tumour suppressor gene (WT-1) and cancer antigen 125 (CA125) but only one expressed renal cell carcinoma (RCC) antigen. Vascular plexus overexpressed nuclear and cytoplasmic WT-1. The VHLD-associated cases appeared to be benign, but the sporadic case exhibited a low malignant potential. CCPCs show histological and immunophenotypical similarities with the recently reported clear cell papillary RCC, although the previously unreported apical CD10 and nuclear PAX2 expression may be related to their mesonephric origin. CCPC has a distinctive sub-epithelial vascular pattern that is consistent with its pathogenesis.