内田 文也¹, 中川 俊一², 樋口 国博³, 三谷 英嗣³, 大井 牧⁴, 松下 智人⁴, 有竹 久⁵, 羶延賢 恵子¹, 宇城 研悟¹, 西村 はるか¹

Fumiya UCHIDA¹, Shunichi NAKAGAWA², Kunihiro HIGUCHI³, Hidetsugu MITANI³, Maki OI⁴, Tomohito MATSUSHITA⁴, Hisashi ARITAKE⁵, Keiko HAMANAKA¹, Kengo USHIRO¹, Haruka NISHIMURA¹

¹松阪市民病院中央検査室, ²松阪市民病院外科, ³松阪市民病院内科, ⁴松阪市民病院放射線科, ⁵松阪市民病院病理検査室

¹Clinical Laboratory, Matsusaka City Hospital, ²Department of Surgery, Matsusaka City Hospital, ³Department of Internal Medicine, Matsusaka City Hospital, ⁴Department of Radiology, Matsusaka City Hospital, ⁵Division of Pathology, Matsusaka City Hospital

キーワード : coded phase-inversion harmonic sonography, contrast-enhanced ultrasonography, inflammatory pseudotumor, Levovist^®, liver

症例は68歳, 男性. II型糖尿病で血糖コントロール不良の患者. 腹部超音波検査スクリーニングにて肝臓S4に辺縁低エコー帯を有する内部不均一な低エコー腫瘤を指摘され精査となった. 造影超音波検査では, early arterial phaseでの腫瘤内部の微細で淡い血管染影像, late vascular phaseでの周囲肝実質とほぼ等エコーで不均一な染影像及び腫瘤内部の散 在性染影欠損像(モザイクパターン), post vascular phaseでの不均一な微細点状高エコーの残存と腫瘍全体の比較的境界明瞭な染影欠損像として観察された. エコーガイド下肝生検を行ったところ, 炎症細胞の浸潤を伴う壊死組織を認め, 悪性腫瘍を示す明らかな所見はみられず, 肝炎症性偽腫瘍と診断された. 今回観察された造影超音波所見は, 腫瘤内部に 肝細胞及び動脈の散在性の残存, 不均一な炎症性細胞の浸潤と中心部壊死といった肝炎症性偽腫瘍の病理組織学的性状をそれぞれ反映している可能性が示された.

A man aged 68 years was admitted to our hospital for control of diabetes mellitus. A routine examination with conventional ultrasonography disclosed an irregular hypoechoic mass 2.4 cm in diameter with a marginal hypoechoic rim in S 4 of the liver. Plain CT showed it as a low-density tumor lower in the periphery than in the central area. Enhanced CT showed slight enhancement during the arterial phase, and high-density spots appeared in the low-density area during the portal venous phase. Contrast-enhanced ultrasonography was performed using the coded phase-inversion harmonic method. An early arterialphase sonogram obtained 20 seconds after a rapid injection of the contrast agent demonstrated enhancement of an artery at edge of the mass and slight enhancement extending into the tumor. Enhancement had spread throughout the tumor by 30 seconds after the bolus injection of the contrast agent. Mosaic enhancement accompanied by small, locally non-enhanced area in the tumor was present in late vascular phase 60 seconds after Levovist^® had been injected. Subsequently, contrast-enhanced ultrasonograms obtained with intermittent scanning in the post vascular phase demonstrated enhancement in only several spots. Ultrasonographically guided needle biopsy was carried out, and microscopic examination revealed infiltration of chronic inflammatory cells and necrotic changes not accompanied by neoplastic cells. Contrast-enhanced ultrasonography may reveal histologic structure in patients with inflammatory pseudotumor of the liver.