Gastrointestinal ImagingHamartoma, splenic
a rare
benign tumour of the spleen composed by an aberrant mixture of normal splenic elements, forming single or multiple masses.
Two types have been described: a white pulp type composed of lymphoid tissue and a red pulp type composed of sinuses and structures similar to red pulp. It was initially described as "splenoma" and has been named also splenoadenoma, fibrosplenoma and nodular hyperplasia of the spleen.
Grossly they appear mostly as well-circumscribed solid lesions of variable size. In most instances the lesions are asymptomatic and are found incidentally at autopsy or at splenectomy. However, splenomegaly may produce left upper quadrant pain.
Plain films may show splenomegaly, and punctate or stellate calcifications. Ultrasound will show a predominantly and homogeneous echoic lesion, with in some instances, internally hyperechoic dots due to calcification. Cystic areas are hypoechoic.
On precontrast CT these masses may have a similar attenuation as the normal spleen and are not revealed unless some calcifications are present. In other cases they are slightly hypoattenuating. Following intravenous contrast medium administration they tend to be hypoattenuating relative to the normal parenchyma of the spleen and become better visible.
Hamartoma of the spleen has been found to be isointense on T1-weighted MRI images and heterogeneous hyperintense or hypointense on T2-weighted images relative to the normal spleen. Linear regions of decreased intensity on T2-weighted images nicely display the fibrotic cords within the tumour. With dynamic gadolinium contrast enhanced sequences, hamartomas show diffuse heterogeneous enhancement.
ALB