An Isolated Hydatid Cyst of the Spleen with High Serum Levels of CA 19-9—A Meaningful Association or Just a Challenge for Diagnosis? A Case Report

An isolated hydatid cyst of the spleen represents an exceptional pathology, and its association with high CA 19-9 serum levels was not previously reported. This case presents a patient with an isolated hydatid cyst of the spleen, with preoperative high CA 19-9 serum levels in the absence of other pathologies and normalization of CA 19-9 serum levels after surgery (i.e., splenectomy). The source and clinical value of high serum levels of CA 19-9 in hydatid cysts of the spleen remains unclear. High serum levels of CA 19-9 in the context of a splenic cyst may complicate diagnosis and challenge the therapeutic strategy.