J Korean Soc Radiol.  2013 Dec;69(6):449-455.

Dynamic CT Findings of Pulmonary Hamartoma: A Comparison with Histopathologic Findings

• Cho W
• Jeong YJ
• Lee CH
• Lee JW
• Kim KI
• Yeom JA
• Kim YD

Abstract

PURPOSE
To describe the dynamic CT findings of pulmonary hamartoma and to compare these findings with histopathologic findings.
MATERIALS AND METHODS
The Institutional Review Board approved this retrospective study and the requirement for patient informed consent was waived. The hemodynamic CT features of 11 patients (M : F = 6 : 5; mean age, 53.6 years) with pathologically proven pulmonary hamartoma were evaluated. All 11 patients underwent enhanced dynamic CT using a helical technique. A series of images were obtained throughout each nodule with 2.5-mm collimation at 0, 30, 60, 90 and 120 seconds and at 4, 5 and 15 minutes after an intravenous injection of contrast medium. Extents and patterns of enhancement were correlated with histologic tumor components.
RESULTS
All 11 tumors showed persistent enhancement with variable degrees of net enhancement [mean tumor peak enhancement, 48.6 +/- 19.0 Hounsfield unit (HU); mean tumor net enhancement, 31.9 +/- 11.8 HU] and thick capsular and septal enhancement. Histologically, all 11 tumors were composed of mature cartilage and loose mesenchymal tissue. A significant positive correlation was found between the net enhancement values and loose connective tissue component percentages (r = 0.749, p = 0.008); further, a negative correlation was found between the net enhancement values and cartilaginous component percentages (r = -0.813, p = 0.002).
CONCLUSION
On dynamic CT, hamartoma exhibited persistent enhancement without washout as well as thick capsular and septal enhancements. Net enhancement values were found to be positively correlated with the proportion of the loose connective tissue component. Thick capsular and septal enhancements were attributed histopathologically to loose connective tissue, separating tumors into cartilaginous lobules.

MeSH Terms

Cartilage
Connective Tissue
Ethics Committees, Research
Hamartoma*
Hemodynamics
Humans
Informed Consent
Injections, Intravenous
Lung Neoplasms
Multidetector Computed Tomography
Pathology
Retrospective Studies

Figure

• 

  Fig. 1 A 39-year-old man (patient 2) with pulmonary hamartoma with persistent (PE, 67 HU; NE, 43 HU) and septal enhancement on dynamic CT. A. Targeted view of a transverse lung window CT scan shows a 13-mm-sized nodule with a lobulated margin in the left upper lobe. B. Targeted view of a transverse mediastinal window CT scan 90 seconds after contrast injection shows peripheral and septal enhancement. C. Sagittal section of an excised specimen in the same patient shows that the tumor consisted of glistening nodules of cartilage separated by clefts. D. Low-magnification photomicrograph shows multiple lobules of mature cartilage intersected by abundant loose connective tissue containing fat and smooth muscle and clefts lined by respiratory epithelium. E. Schema of tumor components, the percentages of cartilaginous component (areas within blue lines) and loose connective tissue components were 53.21% and 46.79%, respectively. Note.-HU = Hounsfield unit, NE = net enhancement, PE = peak enhancement

• 

  Fig. 2 A 54-year-old man (patient 6) with pulmonary hamartoma with persistent (PE, 62 HU; NE, 8 HU) and septal enhancement on dynamic CT. A. Targeted view of a transverse mediastinal window CT scan 5 minutes after contrast injection shows peripheral and septal enhancement. B. Low-magnification photomicrograph shows multiple lobules of mature cartilage with intersecting parse loose connective. C. Schema of tumor components, the percentages of cartilaginous component (areas within blue lines) and of loose connective tissue components were 86.36% and 13.64%, respectively. Note.-HU = Hounsfield unit, NE = net enhancement, PE = peak enhancement

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  Fig. 3 Correlation between dynamic CT NE values and pathologic results. A. The correlation between NE values and loose connective tissue component percentages (r = 0.749, p = 0.008). B. The correlation between NE values and cartilage component percentages (r = -0.813, p = 0.002). Note.-HU = Hounsfield unit, NE = net enhancement

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