HPB P54 First Reported Case of Primary Serous Cystadenocarcinoma of the Spleen

Abstract

Abstract Background Tumours of the spleen are uncommon, and the majority are metastases from primary malignancies in other organs. The two main subdivisions of primary malignancies of the spleen are lymphoid and non-lymphoid. Primary splenic cystadenocarcinomas are extremely rare, and only tumours of the mucinous subtype have been recorded. The spleen usually exhibits secondary infiltration from primary cystadenocarcinomas in other organs such as the ovaries and pancreas. Methods We present the case of an elderly white female who was found to have an incidental splenic tumour. This showed interval increase in size on serial imaging and was confirmed to be a complex mass with a cystic component on MRI. After MDT discussion and further investigations, including FDG-PET, EUS and diagnostic laparoscopy, she underwent a distal pancreatectomy, partial gastrectomy and splenectomy for a presumed tail of pancreas adenocarcinoma. Results The splenic hilum contained a large partly cystic tumour conglomerate measuring up to 5.8cm in maximum dimension, which contained thick, dark red, gelatinous material. It was well-circumscribed and demarcated from the rest of the splenic parenchyma, and the distal pancreas appeared to be uninvolved. Histology showed low columnar to cuboidal cells with moderate to patchy marked nuclear pleomorphism, and no cytoplasmic mucin was identified. The tumour had a predominantly papillary and focal tubular architecture, with hierarchical branching of papillae. The neoplastic cells stained positive for CK7, ER and WT1 expression and negative for CK20 and CA. Conclusions Histological and immunohistochemical analyses were consistent with the first recorded case in the literature of primary serous cystadenocarcinoma of the spleen, which we believe developed through malignant transformation of a benign epidermoid cyst. This is the commonest type of true cysts of the spleen and one which has tumorigenic potential, being able to undergo metaplasia and dysplasia. The patient remains well as per her latest follow-up with no evidence of recurrence or metastases. However, given the rarity of splenic cystadenocarcinomas, uncertainty remains on the long-term prognosis and optimal management of such cancers, including adjuvant treatment options.