鼻咽癌皮膚轉移：一案例報告與文獻探討

Skin Metastases Due to Nasopharyngeal Carcinoma: A Case Report and Literature Review

雖然85%以上鼻咽癌病患的原發部位腫瘤治療成功，但是15–30%的病患會發生遠處轉移，尤其以骨頭、肺部和肝臟的轉移最常見，極少有皮膚轉移的報導。我們報告一位鼻咽癌病患於治療成功4年半之後發生皮膚轉移的案例，一位55歲男性於2017年2月診斷罹患第4期（T1N3M0）非角質化無分化鼻咽癌，於2017年4月接受完整的化學放射治療後，腫瘤完全緩解消失。2021年追蹤的磁振造影發現胸骨上方凹陷處有一1.5 cm的皮下結節。該結節在6個月內逐漸變大為T1等信號，T2稍高信號，且顯影增強的不規則皮下病灶，上方皮膚增厚且呈T2高信號。手術切片的病理診斷為非角質化無分化鼻咽癌。在鼻咽癌遠處轉移的診斷下，病患接受每周一次Cisplatin和23次共7050cGy的化學放射治療三個月後，皮膚轉移病灶完全緩解消失。鼻咽癌發生遠處皮膚轉移的機率大約是0.25%。自1998年迄今，文獻總共有16個案例。此報告是首次呈現磁振造影的鼻咽癌皮膚轉移的案例報告，同時顯示此病灶在正子造影並未有預期的高代謝活性。絕大多數發生皮膚轉移的鼻咽癌患者的初始診斷皆為3期或4期，發生時間距初始診斷在0–54個月之間，大都小於12個月。這些皮膚轉移病灶通常為0.5–3 cm的皮下結節，可能無症狀或造成疼痛。極少數皮膚病灶表現類似帶狀皰疹樣的水泡，或呈紅斑樣灶。絕大多數案例皆同時有骨頭、肺部或肝臟的轉移。目前無有效治療鼻咽癌皮膚轉移的方法，文獻報告的案例都在發生皮膚轉移後的1個月內到10個月死亡，其中半數存活短於6個月。由於鼻咽癌皮膚轉移可能在治癒之後甚至4年半才發生，因此建議詳細的理學檢查與磁振造影追蹤至少5年。正子造影對於鼻咽癌皮膚轉移偵測的敏感性不佳。

More than 85% of patients with nasopharyngeal carcinoma (NPC) have successful locoregional control but 15–30% of these patients experience distant failure. Distant metastases in NPC most frequently occur in bones, lungs and liver. NPC with skin metastasis is rarely reported. This study presents a case of advanced NPC with skin metastases at the suprasternal notch, which occurred more than 4 years after complete remission from the initial malignancy. A 55-year-old male was diagnosed with nonkeratinizing undifferentiated NPC of T1N3M0 (stage IVA) in February 2017. The disease was in complete remission after a full course of concurrent chemoradiotherapy (CCRT) in April 2017.
A 1.5-cm subcutaneous nodule at the suprasternal notch was identified in follow-up magnetic resonance imaging (MRI) scans in August 2021. The lesion enlarged gradually as an irregular-shaped subcutaneous mass with T1-isointensity, mild T2-hyperintensity and vivid enhancement within six months. A MRI scan also identified thickening of the overlying skin with infiltrative T2-hyperintensity, indicating cutaneous lymphedema. An excisional biopsy was performed and metastatic non-keratinizing undifferentiated NPC was confirmed.
CCRT involved weekly Cisplatin and a total of 7050cGy in 23 fractions to control the cutaneous tumor. Complete remission from the skin metastases and edema was achieved about three months after CCRT. The incidence of skin metastases due to NPC is about 0.25%. Only 16 cases have been recorded in the past two decades. This study presents the MRI results for skin metastases that originate from a non-keratinizing undifferentiated NPC, which did not show hypermetabolic activity in 18F-FDG-PET. Most NPC patients with skin metastases initially present at stage III or IV. The interval between initial diagnosis and the development of skin metastases is 0–54 months and mostly within 12 months. These skin lesions usually appear as single or multiple 0.5–3 cm painless or painful subcutaneous nodules. They rarely occur as zosteriform papules or erythematous patches. Concomitant distant metastases in bones, lungs or liver are observed in most NPC patients with skin metastases.
There is no standardized effective treatment for these cutaneous metastases. The survival time ranges from less than one to 10 months after diagnosis of skin metastases. Half of alle patients die within six months. In terms of the possibility of late occurrence of skin metastases in NPC patients, regular surveillance using a detailed physical examination and MRI study for at least five years is required. 18F-FDG-PET alone may be not adequate for the detection of skin metastases due to NPC.