稲吉 厚¹, 清住 雄昭², 坂口 勝哉³, 蔵野 良一⁴

Atsushi INAYOSHI¹, Takeaki KIYOZUMI², Katsuya SAKAGUCHI³, Ryoichi KURANO⁴

¹熊本地域医療センター外科, ²熊本地域医療センター内科, ³熊本地域医療センター臨床検査室, ⁴熊本地域医療センター病理

¹Department of Surgery, Kumamoto Regional Medical Center, ²Department of Internal Medicine, Kumamoto Regional Medical Center, ³Department of Clinical Laboratory, Kumamoto Regional Medical Center, ⁴Department of Pathology, Kumamoto Regional Medical Center

キーワード : Hamartoma, Inflammatory pseudotumor , Lymphangioma, Spleen, Ultrasonography

Benign mass lesions of the spleen have rarely been reported in the literature. Between 1988 and 1995, however, we experienced four benign mass lesions of the spleen: two patients had hamartoma, one had inflammatory pseudotumor, and one had lymphangioma. Splenectomy was performed after ultrasound examination of the splenic masses, and three of the four resected specimens were examined by ultrasound again. We then studied the correlation between the ultrasonograms and the pathologic findings. Hamartomas of the spleen were demonstrated in the ultrasonograms by isoechoic or hypoechoic patterns, and the internal echoes were either homogeneous or heterogeneous. We believe that a marginal hypoechoic zone reflects a fibrous trabecula, as we reported in splenic hemangioma. Heterogenicity of internal echo pattern seemed to reflect a combination of fibrous trabeculae and dilated vessels. Inflammatory pseudotumors produced heterogeneous hypoechoic patterns with unclear margins, and high echo accompanied by acoustic shadow appeared in the mass. Pathological examination showed fibrosis with widespread degeneration into the tumor. Hyaline degeneration was seen in a small portion of the mass, and we suspect that hyaline degeneration was the origin of the high echo accompanied by acoustic shadow. Lymphagioma of the spleen produced a mixed pattern consisting of a hyperechoic and a cystic area. We suspect that the hyperechoic area reflects the gathering of many small lymphatic vessels, and that the cystic area reflects a large lymph vessel.