Atypical MRI presentation of a small splenic hamartoma

Hamartomas of the spleen usually appear isointense on T1-weighted MR images and hyperin tense on T2-weighted images. We describe a histologically prov en case which presented as a small (2.5 cm) focal mass isointense to spleni c parenchyma on T1-weighted images and hypointense on both turbo-spin-echo T2 and short T1 inversion recovery images. Dynamic MRI revealed a delayed e nhancement during the arterial phase becoming isointense and prolonged on s ubsequent images. This prolonged enhancement has previously been described as a characteristic pattern in these tumours. The lack of oedema and necros is and the presence of fibrous tissue in the hamartoma at histopathology li kely account for the low signal intensity on all sequences.