Pseudotumors are rare mass lesions. They have been reported in various organs including the orbit, respiratory tract, gastrointestinal tract, lymph nodes, soft tissues, heart, and liver. Pseudotumors of the spleen are particularly uncommon with fewer than 70 cases reported in the medical literature. Cotelingam and Jaffe were the first to report on two cases of splenic pseudotumor in 1984.
The exact pathogenesis and etiology of splenic pseudotumor remains obscure. Various hypothesis have been proposed regarding its development and include autoimmune, infectious (especially with Epstein-Barr virus), vascular, inflammatory, and post-traumatic causes. To date, none of the theories has been conclusively proven. The term inflammatory pseudotumor, however, is frequently applied to these lesions since they are composed primarily of plasma cells and lymphocytes in a fibroblastic stroma.
Clinical presentation: Splenic pseudotumor can occur over a large age range, but is most often seen in the middle and older age populations. No gender predisposition has been identified. Patients are typically asymptomatic, but may present with left flank pain or splenomegaly. No serum abnormalities have been shown to be consistently present in all patients with the disorder.
Imaging: On ultrasound, splenic pseudotumor typically demonstrates-
1. A large, well-circumscribed splenic mass.
2. Central necrosis and partial calcification can also be seen with these lesions.
The imaging characteristics of splenic pseudotumor on CT, MRI, and US normally lack the specificity to differentiate this benign disorder from other benign and malignant neoplasms of the spleen. Franquet, et al., however, reported that the presence of a central stellate area corresponding to a fibrous plaque on CT after contrast administration is strongly suggestive of an inflammatory pseudotumor.
Differential diagnosis: The differential considerations during the radiographic evaluation of splenic pseudotumor include lymphoma, hamartoma, hemangioma, lymphangioma, plasmocytoma, and splenic hydatid cyst. The definitive diagnosis of a splenic pseudotumor is made histopathologically.
Management: The prognosis of pseudotumor of the spleen is generally considered favorable. No reports of metastatic disease, local invasion, or recurrence following splenectomy have been reported in the literature in association with the disorder.