A splenic 'cyst': histology confirmed splenic sarcoma.

Primary malignant fibrous histiocytoma, now classified as pleomorphic undifferentiated sarcoma, is the most common soft-tissue sarcoma in adult life. Primary splenic pleomorphic undifferentiated sarcoma is extremely rare and aggressive, and is associated with a poor prognosis; only 14 cases of splenic pleomorphic undifferentiated sarcoma have been documented in the English literature. We discuss a case of a 56-year-old woman with iron-deficiency anaemia, early satiety and left upper-quadrant pain, who was preoperatively diagnosed with a large splenic cyst following thorough investigation. This was excised in an elective procedure. Unfortunately, histology confirmed splenic pleomorphic undifferentiated sarcoma. Following a review and summary of the literature, we discuss key differentials between splenic cysts and splenic pleomorphic undifferentiated sarcoma. This case highlights that iron-deficiency anaemia is unusual in splenic cysts and more sinister causes must be considered.