周邊神經包膜瘤的電腦斷層影像表徵

Computed Tomography of Peripheral Nerve Sheath Tumors

曾修山(Hsiuo-Shan Tseng) ； 周宜宏(Yi-Hong Chou) ； 張政彥(Cheng-Yen Chang) ； 鄧木火(Michael-Mh Teng) ； 張遵(Tsuen Chang)

《中華放射線醫學雜誌》 17卷3期 (1992/09) Pp. 247-254

摘要

回溯分析台北榮總自1983至1991年間，57個經手術及病理證實為周邊神經包膜瘤的電腦斷層攝影(CT)影像。其中包括38個神經鞘瘤，17個神經纖維瘤，和2個惡性神經纖維瘤。所有腫瘤均接受注射顯影劑電腦斷層攝影。其中16個神經鞘瘤，8個神經纖維瘤，和2個惡性神經纖維瘤，包含無顯影劑電腦斷層攝影。大部份的周邊神經包膜瘤在無顯影劑電腦斷層攝影為界限清楚，均勻或稍不均勻的低密度腫瘤。而注射顯影劑之後，25個神經鞘瘤，11個神經纖維瘤，和2個惡性神經纖維瘤的密度明顯上昇；有6個神經鞘瘤和1個神經纖維瘤的密度甚至相近或等於鄰近血管。35個神經鞘瘤，13個神經纖維瘤，和2個惡性神經纖維瘤呈明顯的不均勻狀，其型態可分為：(1)瑞士乾酪狀(Swiss-cheese appearance)，(2)多孔狀，(3)一個大的低密度區，(4)一個較大的低密度區和數個小的低密度區，或(5)其它。我們認為瑞士乾酪狀是具特異性的CT表徵，在其它軟組織腫瘤為罕見；而於本研究中38個神經鞘瘤有10個，17個神經纖維瘤有1個，可以見到此種影像。因此，如果一個軟組織腫瘤，在無顯影劑電腦斷層攝影為界限清楚均勻的低密度病灶，注射顯影劑後，密度明顯增加，而呈瑞士乾酪狀表徵，則需要高度懷疑是周邊神經包膜瘤，特別是神經鞘瘤。

關鍵字

周邊神經包膜瘤 ； 神經鞘瘤 ； 神經纖維瘤 ； 電腦斷層攝影

並列摘要

We retrospectively analyzed the computed tomographic (CT) appearances of 57 peripheral nerve sheath tumors which were proved by operation and histopathology between 1983 and 1991 in VGH-Taipei. They included 38 schwannomas, 17 neurofibromas, and 2 malignant schwannomas in 53 patients. All the patients received contrast-enhanced CT scan, but only 16 patients with schwannoma, 8 with neurofibroma and 2 with malignant schwannoma had non-contrast CT scan. Most of the peripheral nerve sheath tumors presented as well-circumscribed, homogeneous, low-density lesions in non-contrast CT scan. After intravenous' contrast injection, 25 schwannomas, 11 neurofibromas and 2 malignant schwannomas showed obvious increase of density. Six schwannomas and 1 neurofibroma were even equal to its neafby blood vessels in density. In- homogeneous appearance was also demonstrated in 35 schwannomas, 13 neurofibromas and 2 malignant schwannomas. The inhomogeneity could be classified as 1) Swiss-cheese appearance, 2) multiple small, low-attenuation areas, 3) a large central cavity, 4) a larger cavity with several small, low-attenuation areas, and 5) others. According to literature, the Swiss-cheese appearance is a rare presentation in other kinds of soft tissue tumors, while in our study, 10 of 38 schwannomas and 1 of 17 neurofibromas showed Swiss-cheese appearance. In conclusion, if a soft tissue tumor is well-circumscribed and homogeneously hypodense in noncontrast CT scan, and appears hyperdense with Swiss-cheese appearance in contrast-enhanced CT scan, a peripheral nerve sheath tumor, particularly schwannoma, should be highly suspected.

並列關鍵字

nerve sheath tumors ； schwannoma ； neurofibroma ； computed tomography