Splenic lesions can be broadly categorized into soloid and cystic types. For cystic lesions, it is important to determine whether the cysts are solitary or multiple. Solitary cytic lesions of spleen are typically benign.

If a solitary cyst is present within the spleen, the potential differenctial diagnosis are outlines below.

1)Epithelial cysts are typically well defined and unilocular , with thin barely preceptible wall. They rarely exhibit calcifications and do not enhance on post contrast imaging.

2)Pseudocysts are benign, well circumscribed , unilocular cysts with thick, progressively enhancoing walls, which may or may not exhibit calcifications. They may contain hemosiderin deposits and fluid that ranges from simple to minimally complex.

3)Echinococcal cysts are well-defined lesionsthat may occasionally contain daughter cysts. They are non-enhancing and appear hyperintense compared to simple fluid on T1w MR scans.

The differenctials for multiple splenic cysts are discussed below.

1) Multiple abscess- These are typically thick walled lesions with peripheral rim enhancement visible on both CT and MRI. Common causes include fungal infections and tuberculosis. Intreated cases, calcifications may be scattered throughout the spleen.

Pyogenic abscess are usually solitary and large, characterised by the presence of air fluid level,which help in distinguishing them from other types of splenic cysts.

2)Lymphangiomas: Typically well defined, thin walled multilocular structurees filled with fluid. Fibrous tissue within the lesion may appears as septa, which can occasionally contain calcifications. On post contrast imaging, these lesions often demonstrate progressive enhancement, aiding in their identification and differentiation from other splenic abnormalities.

Solid vascular splenic lesions differencials include haemangioma, hamartoma,SANT, littoral cell angiomas, angiosarcoma.

1)Haemangiomas are typically solitary and rarely occur in a diffuse form. On MRI, they exhibit hyperintense T2w signal intensity when compared to the spleen. post-contrast imaging on both CT and MRI often reveals either immediate homogenous enhancement or progressive enhancement  with presistent delayed enhancement.

2)Hamartomas aretypically solitary, well circumscribed lesions that are oftern large enough to cause a bulging contour on the spleen. On ultrasound, they appear hypoechoic with increased vascularity. On MRI, these lesions demonstrate hyperintense T2w signal relative to spleen. Post contrast imaging shows vivid enhancement on early post contrast images, followed by uniform intense enhancement on delayed images.

3)Sclerosing angiomatoid nodular transformation(SANT) of the spleen presents as a solitary, well-defined solid lesion. A characteristic imaging feature is the "spoke-wheel" enhancement pattern, characteriseed by early rim enhancement followed by progressive centripetal radial enhancement of fibroud bands and nodules. On ultrasound, the lesion appears hypoechoic. On T2-weighted MRI, hypointense radiating fibrous bandsare a notable feature.

4)Litteroal cell angioma(LCA)- Typically present as multiple progressively enhancing nodules within the spleen. On MRI, they exhibit variable T2-weighted signal intensities. Hypercellular littoral cell angiomas show increased T2 signal on MRI, while the presence of hemosiderin leads to decreased T2 signal.

5)Angiosarcoma

• Discrete angiosarcoma: solitary to few well-circumscribed masses
• Diffuse angiosarcoma: splenomegaly, heterogeneous enhancement of irregular or poorly defined nodular vascular masses

Differential diagnoses for solid non vascular lesions of spleen include lymphoma, inflammatory pseudotumour, inflammatory masses like sarcoidosis and metastasis.

1)Lymphoma is the most common malignant tumor of the spleen, typically secondary in nature and is associated with splenomegaly. It appearance can vary, ranging from tiny diffuse miliary nodules to small or large nodules. On MRI, lymphoma typically shows a homogenous T2 hyperintense signal, with diffusion restriction and hypoenhancement compared to the spleen. FDG PET/CT scans will show increased metabolic activity.

2) Inflammatory pseudotumor(IPT) is a reactive tumor like lesion found throughout the body, rarely in the spleen. It appears as a solitary wall circumscribed solid mass like lesion on ultrasound scan. Hypoenhancing well circumscribed solitary mass on Ct scan with progressive enhancement of the fibrous component.Calcifications may be present. The lesion is T1 iso to hypointense signal with hetrogenous signal on T2, with low signal intensity fibrous scar showing progressive enhancement.

3) Inflammatory: Sarcoidosis is the main differenctials. Numerous tiny hypoechoic lesions on ultrasound scan. They are hypointense with all MRI sequences. Hypoenhancing solid nodules on CT/MRI.

4)Metastases: Uncommon, melanoma is a differential to include. They are almost exclusively in patients with known or widespread cancer.

Other splenic pathologies include traumatic splenic laceration, spontaneous splenic rupture and splenic infarction.