The majority of splenic lesions are benign and when an incidental splenic lesion is found in an asymptomatic patient, it may pose a dilemma in workup because imaging findings are often nonspecific.
- benign imaging features: no follow up
- imperceptible wall
- well-marginated
- homogeneous
- <10-20 HU
- does not enhance after contrast
- splenic hemangioma does not typically demonstrate peripheral nodular discontinuous enhancement
- not definitely benign features
- prior imaging
- unchanged over one year: no follow up
- changed over the past year: MRI, PET, or biopsy follow up
- no prior imaging
- history of cancer
- <1 cm: follow up MRI in 6 and 12 months
- ≥1 cm: MRI, PET, or biopsy follow up
- no history of cancer
- indeterminate features: follow up MRI in 6 and 12 months
- smooth margins
- enhancement after contrast
- >20 HU
- heterogeneous
- suspicious features: MRI, PET, or biopsy follow up
- marked enlargement
- splenic or vascular invasion
- necrosis
- irregular margins
- enhancement after contrast
- heterogeneous
- indeterminate features: follow up MRI in 6 and 12 months
- history of cancer
- prior imaging
Practical points
- even with a known malignancy, an incidental lesion <1 cm is thought to most likely represent a benign finding, although this is extrapolated from incidental hepatic lesion data
- primary splenic lymphoma is uncommon, look for other enlarged nodes before suggesting splenic lymphoma as a diagnosis
- splenic hemangiomas do not tend to enhance in a similar way to hepatic hemangiomas (peripheral nodular discontinuous enhancement) 2
- primary malignancy of the spleen is rare