Small rounded hypodense shadows in the spleen are usually splenic cysts, which are benign cystic lesions in the spleen.
The causes of splenic cysts can be categorized as parasitic and non-parasitic. Parasitic splenic cysts are most common in the northern pastoral areas of China and are mainly caused by Echinococcus tapeworm infection. Non-parasitic cysts are mainly caused by congenital genetic defects resulting in splenic hypoplasia and secondary causes such as abdominal trauma and splenic rupture.
Splenic cysts are asymptomatic when they are small, but when they are too large, they may compress the surrounding organs and cause discomfort in the left upper abdomen. When the cyst ruptures, hemorrhage and secondary infection causing acute peritonitis may occur.
There may be other causes for the small rounded low-density shadows seen in the spleen, and the patient needs to consult a doctor in time for diagnosis by ultrasound or CT, after which general medication or surgical treatment can be performed under the guidance of the physician.