Splenic hemangiomas are rare, but are the most prevalent of all tumors of the spleen. These lesions are mostly asymptomatic and are often detected as incidental findings while performing abdominal ultrasounds for other reasons. Rarely are the patients symptomatic. When present, symptoms may be due to hemorrhage from spontaneous or traumatic rupture of a hemangioma. A few patients present with splenomegaly.
Splenic hemangiomas may be single or multiple and usually present as a hyperechoic mass in the spleen. By ultrasound their detection rate is estimated to be around 1%. Autopsy studies have shown the incidence rate of splenic hemangiomas to range from 0.03-14%. Most of these are silent; however a few studies have reported spontaneous rupture of a splenic hemangioma in about one-fourth of patients in the series. In such a scenario, splenectomy is often necessary.
Ultrasound is often the initial modality used to diagnose splenic lesions, and when in doubt, a contrast enhanced CT or MRI scan is performed to characterize the lesions further. Studies have shown that color Doppler can sometimes demonstrate characteristic flow patterns in focal lesions [based on patterns of blood flow within and around the tumors] that can aid in diagnosing doubtful cases. In most cases the flow within the hemangiomas is so slow that they appear to be hypovascular.
The closest differential is splenic metastases, arising from a melanoma, ovarian, pancreatic or any GI malignancy. Other rare hyperechoic appearing tumors include hemangiosarcoma and sometimes echogenic lymphomatous deposits [although classically the lymphomatous deposits are hypoechoic]. A recently discovered hyperechoic tumor to be considered is a Littoral cell angioma, which is a benign vascular tumor. Littoral cells are cells lining the splenic sinuses. No definite sonographic pattern of the tumor has been described, although a study reported that patients with these tumors typically present with splenomegaly and multiple focal nodular hyperechoic masses.
In the case discussed here, a contrast enhanced CT was performed, which demonstrated the typical contrast enhancement pattern for hemangiomas [peripheral enhancement followed by slow filling of the lesion with contrast].