Incidentally discovered asymptomatic splenic hamartoma with rapidly expansive growth: a case report

Splenic hamartoma (SH) is a very rare benign vascular lesion, usually asymptomatic. Although infrequent, it must be differentiated from malignant lesions, such as lymphoma or metastases, or other vascular neoplasms of the spleen. We present the case of a solid lesion of the spleen discovered incidentally in a 42-year-ol women, characterized by an unusual rapid expansive growth during four-month follow-up. The lesion, isoechoic and close to the hilum, was initially suspected to be an accessory spleen, measuring 3.5 cm in size. Four months later, magnetic resonance imaging revealed a 9-cm expansive nonhomogeneous mass in the antero-superior margin of the spleen, dislocating the stomach. The lesion exhibited central necrosis with hyper- and hypointense signal both in T1 and T2-weighted images. Due to the risk of spontaneous rupture and because malignancy could not be ruled out, the patient underwent hand-assisted laparoscopic splenectomy. Macroscopically, the spleen measured 15×12×4 cm and weighed 890 g. Cut sections revealed a single nodule of dark-red tissue sized 8.5 cm. The lesion exhibited a network of irregularly arranged and tortuous vascular channels lined by endothelium similar to splenic sinus lining cells, surrounded by aggregates of lymphocytes and macrophages resembling the pulp cords. On immunohistochemical staining the tissue was CD34 - and CD8 + and the final diagnosis was SH. In conclusion, when SH is suspected and malignancy cannot be ruled out, hand-assisted splenectomy should be considered the procedure of choice. Partial splenectomy should be preferred in children, to avoid potential risks of total splenectomy.