沖野 久美子¹, 若杉 聡², 市原 真³

Kumiko OKINO¹, Satoshi WAKASUGI², Shin ICHIHARA³

¹北海道医療大学医療技術学部臨床検査学科, ²公立学校共済組合関東中央病院内科, ³札幌厚生病院病理診断科

¹Department of Clinical Laboratory Medicine, School of Medical Technology, Health Sciences University of Hokkaido, ²Department of Internal Medicine, Kanto Central Hospital of the Mutual Aid Association of Public School Teachers, ³Department of Surgical Pathology, Sapporo Kosei General Hospital

キーワード : fatty change, hyperechogenic hepatic lesion, pseudoglandular pattern, peliotic change, sinusoidal dilation

肝臓限局性病変の同定と正確な診断は現代医療において極めて重要であり，画像診断はその中核を担う．本総説では，相対的高エコーを呈する肝臓限局性病変の組織病理学的特徴を概観した．肝内で高エコーを示す病変には良性と悪性の双方が存在する．高エコー像は主として脂肪沈着，類洞拡張，ペリオーシス（紫斑様変化），および偽腺管パターンといった因子によって生じることが示されている．脂肪沈着は肝細胞癌（hepatocellular carcinoma: HCC）のエコー輝度上昇の主要因であり，類洞拡張とペリオーシスは比較的大きなHCC結節で頻繁に観察される．多数の偽腺腔壁で超音波が反射される偽腺管パターンは，高分化から中分化のHCCにおける高エコー像と関連する．加えて本総説では，HCCのみならず，腺癌および神経内分泌腫瘍の肝転移，肝内胆管癌，海綿状血管腫，限局性結節性過形成，血管筋脂肪腫などの限局性肝病変において，高エコーを生じ得る組織病理学的特徴を体系的に取り上げた．正確な診断と適切な管理を行うためには，限局性肝病変に認められる高エコー像の組織病理学的根拠を理解することが不可欠である．画像診断の精度を最大限に高め，画像・病理相関を強化することは，不要な生検を回避し，合併症や死亡率の低減につながる．本総説は，限局性肝病変患者の効果的な管理を促進し，適時かつ適切な治療意思決定に資することを目的とする．

The identification and accurate diagnosis of focal liver lesions are important in modern medicine, where diagnostic radiology plays an essential role. This review aimed to examine the hyperechogenicity and histopathological features of focal liver lesions. Hyperechogenic liver lesions can be either benign or malignant. Evidence shows that hyperechogenicity is caused by factors such as fat deposition, sinusoidal dilation, peliotic changes, and pseudoglandular patterns. Fat deposition is a common cause of increased echogenicity in hepatocellular carcinoma （HCC）. Meanwhile, sinusoidal dilation and peliotic changes are more frequently observed in larger HCC nodules. Pseudoglandular patterns, characterized by the reflection of ultrasound waves at the walls of numerous acini, are associated with hyperechogenicity in well-to-moderately differentiated HCCs. Moreover, this review comprehensively examined the histological features that may cause hyperechogenic internal echoes in not only HCCs but also localized liver lesions （metastases of adenocarcinoma and neuroendocrine neoplasm, intrahepatic cholangiocarcinoma, cavernous hemangioma, focal nodular hyperplasia, and angiomyolipoma）. To make an accurate diagnosis and provide appropriate management, it is important to understand the histopathological basis for hyperechogenicity in focal liver lesions. By maximizing the accuracy of imaging studies and enhancing the radiology–pathology correlation, unnecessary biopsies can be avoided, thereby reducing potential complications and mortality. This review can help facilitate the effective management of patients with focal liver lesions, thereby resulting in timely and appropriate treatment decision-making.