外耳道鳞癌 (Squamous Cell Carcinoma of the External Auditory Canal )MRI病例图片影像诊断分析颞骨 2010-10-22
【病史临床】53岁男性诉右侧耳痛并排出血性物质，初步的临床检查显示外耳道肿块。53-year-old male came with complaints of right ear ache and bloody discharge from the ear. Preliminary clinical examination revealed a mass in the external auditory canal.
【影像改变】：图1、2、4、5平扫，图3、6增强扫描。在外耳道内可见一软组织肿块影，T1序列上呈等信号，T2序列上呈高信号，增强扫描有强化。中耳受侵，但不伴有颅内扩展。颈内动脉未见受累。Figure 1, Figure 2, Figure 4, Figure 5 are axial and coronal T1 and T2 weighted images respectively. Figure 3 and Figure 6 are post contrast T1 weighted fat saturated images. A soft tissue mass is seen in the above images in the external auditory canal appearing isointense on T1 images and hyperintense on T2 images with post contrast enhancement (yellow arrows). The middle ear is invaded with no intracranial extension. The internal carotid artery is uninvolved.
【影像诊断】：外耳道鳞癌 Squamous Cell Carcinoma of the External Auditory Canal
- Suspect the diagnosis of SCC in a patient with history of radiation therapy and a mass in the external auditory canal. 当病人有放疗病史，外耳道内出现肿块时，需要考虑到鳞癌的诊断。
- Look for involvement of the middle ear or dural invasion & nodal metastasis, presence of either of which adversely affects the prognosis and survival.寻找中耳受累、硬膜受侵及淋巴结转移的征像，以上征像是否出现决定了本病的预后和存活率。
【讨论】：Carcinomas of the external auditory canal are rare and form less than 0.2% of head and neck malignancies. Various histological subtypes have been described, the commonest being squamous cell carcinoma followed by adenoid cystic carcinoma.
Squamous cell carcinoma of the external auditory canal is predominantly a disease of the elderly with slight male preponderance. Exposure to radiation therapy for head and neck malignancies, especially nasopharyngeal carcinoma, is a risk factor. The tumor is locally aggressive with a relatively lower tendency to metastasize.
Patients typically present with otorrhea, otalgia, and bloody discharge from the ear. Visible necrotic mass, swelling, tinnitus, hearing loss, facial palsy, otitis externa and otitis media are other presenting features.
Extent, description and staging of the tumor is based primarily on imaging as the region is inaccessible to a complete and satisfactory clinical examination. CT scan of the temporal bone is a routine investigation, and is done to look for bony erosion. Small tumor extent and more outer location of ear malignancy such as the auricle or external ear canal has better prognosis with a higher 5-year survival rate.
Surgical excision is the mainstay of management. There is no consensus over the surgical procedure and approaches vary from enbloc resection to piecemeal removal of the tumor. Invasion of the carotid, middle or posterior fossa renders the tumor inoperable. Any nodal involvement is regarded as advanced disease (stage III and IV) and changes the stage irrespective of the T status of the University of Pittsburgh TNM Classification.
In early stages the tumor is treated by en bloc resection, confirming negative margins, with post operative radiotherapy not offering a documented survival advantage over surgery alone. On the other hand, in advanced stages surgery is routinely followed by radiation and topical chemotherapy (5-FU mostly).
在早期肿瘤在确定为受累的边界后，采取整体切除，术后的放疗并不会比单纯的手术有更高的生存率。另一方面，在晚期，手术通常是在放疗或化疗后才进行。(参考来源:,ACR Friday, December 11, 2009,作者:freemanpyw )