Kashiwagi Nobuo, Murakami Takamichi, Chikugo Takaaki, Tomita Yasuhiko, Kawano Kiyoshi, Nakanishi Katsuyuki, Mori Kazunori, Tomiyama Noriyuki
Department of Radiology, Kinki University School of Medicine, Osaka, Japan.
Acta Radiol. 2012 Apr 1;53(3):303-6. doi: 10.1258/ar.2011.110389. Epub 2012 Jan 27.
Carcinoma ex pleomorphic adenoma (CXPA) is a rare aggressive epithelial malignancy arising from a primary or recurrent benign mixed tumor. Only a few case reports describing the radiologic features of CXPA have been published.
To describe and characterize the magnetic resonance (MR) imaging findings of CXPA in the parotid gland and correlate them with pathologic findings.
The MR images of surgically proven CXPA in the parotid gland of five men and five women ranging in age from 28 to 75 years (mean 52 years) were retrospectively reviewed. All MR images were evaluated with emphasis on the size, margin characteristics, extraparotid infiltration, the presence of an encapsulated component, and signal intensity on T2-weighted or short-inversion-time inversion recovery (STIR) images.
The average maximal diameter was 4.3 cm. All 10 tumors had ill-defined boundaries, and seven tumors showed extraparotid infiltration, reflecting invasive growth of the malignant component identified on histological examination. Eight tumors had a round encapsulated component and seven of those signal intensities were a mixture of hypo- and hyperintensity on T2-weighted or STIR images. Histological correlation of these components revealed fibrously encapsulated tumors containing hyalinization and myxoid tissue, suggesting degenerated pleomorphic adenoma. Invasive malignant components had non-specific and various signal intensities.
An invasive parotid mass co-existing with a round encapsulated component is suggestive of carcinoma ex pleomorphic adenoma.
多形性腺瘤恶变（CXPA）是一种罕见的侵袭性上皮恶性肿瘤，起源于原发性或复发性良性混合瘤。仅有少数描述CXPA放射学特征的病例报告发表。
描述并表征腮腺CXPA的磁共振（MR）成像表现，并将其与病理结果相关联。
回顾性分析5例男性和5例女性腮腺CXPA患者的MR图像，患者年龄范围为28至75岁（平均52岁）。所有MR图像均重点评估大小、边缘特征、腮腺外浸润、有无包膜成分以及T2加权或短反转时间反转恢复（STIR）图像上的信号强度。
平均最大直径为4.3 cm。所有10个肿瘤边界不清，7个肿瘤显示腮腺外浸润，反映了组织学检查中确定的恶性成分的侵袭性生长。8个肿瘤有圆形包膜成分，其中7个在T2加权或STIR图像上信号强度为低信号和高信号的混合。这些成分的组织学相关性显示纤维包膜肿瘤含有玻璃样变和黏液样组织，提示多形性腺瘤退变。侵袭性恶性成分具有非特异性且多样的信号强度。
与圆形包膜成分共存的侵袭性腮腺肿块提示多形性腺瘤恶变。
