Korean J Radiol.  2012 Oct;13(5):586-593. 10.3348/kjr.2012.13.5.586.

Histologic Characteristics of Hepatocellular Carcinomas Showing Atypical Enhancement Patterns on 4-Phase MDCT Examination

• Kim I
• Kim MJ

• KMID: 1392937
• DOI: http://doi.org/10.3348/kjr.2012.13.5.586

Abstract

OBJECTIVE
To retrospectively define which histologic characteristics of small-sized hepatocellular carcinomas (HCCs) are related to atypical dynamic enhancement on multi-detector computed tomography (MDCT) imaging.
MATERIALS AND METHODS
Seventy-three patients with 83 HCCs (3 cm or less in diameter) were included in this study. All patients underwent 4-phase MDCT imaging and subsequent surgery within eight weeks. Two independent radiologists blinded to the histologic findings retrospectively classified the HCCs as either typical (showing increased enhancement on arterial phase images followed by washout in late phase images) or atypical lesions demonstrating any other enhancement pattern. From the original pathologic reports, various histologic characteristics including gross morphology, nuclear histologic grades, presence of capsule formation, and capsule infiltration when a capsule was present, were compared among the two groups.
RESULTS
An atypical enhancement pattern was seen in 30 (36.2%) of the 83 HCCs. The mean size of atypical HCCs (1.71 +/- 0.764) was significantly smaller than that of typical HCCs (2.31 +/- 0.598, p < 0.001). Atypical HCCs were frequently found to be vaguely nodular in gross morphology (n = 13, 43.3%) and to have grade I nuclear grades (n = 17, 56.7%). Capsule formation was significantly more common in typical HCCs (p < 0.001). Capsular infiltration was also more common in typical HCCs (p = 0.001).
CONCLUSION
HCCs showing atypical dynamic enhancement on MDCT imaging are usually smaller than typical HCCs, vaguely nodular type in gross morphology in most cases, and well-differentiated in nuclear grades, and they lack of capsule formation or capsular infiltration.

Keyword

Hepatocellular carcinoma; MDCT; Enhancement pattern; Histology

MeSH Terms

Adult
Carcinoma, Hepatocellular/pathology/*radiography/surgery
Chi-Square Distribution
Contrast Media/diagnostic use
Diagnosis, Differential
Female
Humans
Image Enhancement
Iohexol/analogs & derivatives/diagnostic use
Liver Neoplasms/pathology/*radiography/surgery
Male
Middle Aged
Radiographic Image Interpretation, Computer-Assisted
Retrospective Studies
Tomography, X-Ray Computed/*methods

Figure

• 

  Fig. 1 43-year-old man with underlying B-viral hepatitis. (A) Precontrast, (B) hepatic arterial, (C) portal venous, (D) equilibrium phase images from 4-phase multi-detector CT scan. Hypoattenuating lesion (arrow) is seen on precontrast phase image (A). Lesion (arrow) shows increased arterial enhancement on arterial phase image (B) and washout of contrast enhancement on portal venous (C) and equilibrium phase images (D). (E) Gross specimen of lesion (arrow). Histologic examination demonstrated poorly differentiated (nuclear grade III) hepatocellular carcinoma of expanding type gross morphology with partial capsule formation and infiltration.

• 

  Fig. 2 49-year-old man with B-viral liver cirrhosis. (A) Precontrast, (B) hepatic arterial, (C) portal venous, (D) equilibrium phase images from 4-phase multi-detector CT scan. On precontrast (A) and arterial phase (B), lesion (arrow) showed isoattenuation compared to surrounding parenchyma. On portal venous (C) and equilibrium phase (D), lesion (arrow) shows hypoattenuation compared to surrounding parenchyma. (E) Gross specimen of lesion (arrow). Histologic examination showed well-differentiated (nuclear grade I) hepatocellular carcinoma of vaguely nodular type in gross morphology without capsule formation.

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