What’s the relationship between a mole and skin cancer? How many types of skin cancer are there, and how does a doctor make a diagnosis?
很多時候皮膚癌的表徵，跟一般的墨痣分別不會很大。但是在經驗醫生的眼中就可以分辨到良性與惡性。有臨床研究顯示，身體上的黑色墨痣越多，患上黑色素瘤的機會就越大。這和遺傳，及基因都有關係。
香港常見的皮膚癌有三種。最常見的是（1）基底細胞皮膚癌。 第二常見的是（2）鱗狀細胞皮膚癌第三種最常見（即是三個之中最罕見的），就是（3）黑色素瘤。大家最常聽到的「A B C D E」口訣去辨認皮膚癌，只能辨認出最罕見的黑色瘤。
（1）基底細胞皮膚癌症狀：腫瘤外表的圓潤光亮半透明，以及有細小的微血管。在白種人的皮膚裡，腫塊可能呈現珍珠白或粉紅色。在黃種人或深色皮膚的人種，這半透明的腫塊可能呈現棕色或亮黑色。在任何顏色的皮膚都可見細微血管，但這些血管在棕色和黑色皮膚上可能很難察覺。這種腫塊可能引發出血和結疤。有時候腫塊邊界略微凸起且為半透明狀。
（以下五幅照片就是基底細胞皮膚癌案例，在香港非常常見）（在普通人的眼裏這些癌症的外表跟普通墨痣的外觀沒有很大分別，容易混淆）
Very often, early stage skin cancers don’t look very different from ordinary moles. But a trained doctor can distinguish between benign and malignant lesions. Clinical studies show that the more moles you have, the higher the risk of you developing melanoma—a risk influenced by both genetics and heredity.
There are three main types of skin cancer commonly seen in Hong Kong:
1. Basal cell carcinoma (BCC) – the most common.
2. Squamous cell carcinoma (SCC) – the second most common.
3. Melanoma – the rarest among the three, but the most deadly.
Many people have heard of the “ABCDE” rule for diagnosing skin cancer, but it’s mainly used to identify melanoma, the rarest form.
(1) Basal Cell Carcinoma – Symptoms: These tumors tend to be round, shiny, and translucent, often with fine blood vessels visible on the surface. In fair-skinned individuals, the growth may appear pearly white or pink. On darker skin, the same lesion may appear brown or glossy black. Although visible blood vessels can occur in all skin tones, they may be harder to detect on darker skin. These growths can also bleed or scab, and sometimes have raised, translucent edges.
(The five images that follow are cases of basal cell carcinoma, which is very common in Hong Kong. To an untrained eye, these cancers can look remarkably similar to ordinary moles, making them easy to overlook.)
（2）鱗狀細胞皮膚癌的症狀：紅色硬結節伴有鱗狀痂的扁平瘡，舊疤或潰瘍上的新生瘡或突起區域，若沒有出血，可能會呈咖啡色的突起結痂。嘴唇上的不平鱗狀斑塊，可能發展為開放性瘡口，口內紅色瘡或不平斑塊，肛門上或肛門內或生殖器上的紅色突起斑塊或肉疣樣瘡。
（以下照片就是鍾經略醫生鱗狀細胞皮膚癌案例）
(2) Squamous Cell Carcinoma – Signs and Symptoms:
A firm, red nodule or bump that doesn’t go away
A flat sore with a scaly crust, often mistaken for a non-healing wound
A new sore or raised area on an old scar or chronic sore
A rough, scaly patch on the lip that may become an open sore
A sore or rough patch inside the mouth
A raised, wart-like lesion on or near the genitals or anus
A brown spot that resembles an age spot
A horn-like growth (called a cutaneous horn) in rare cases
These lesions may itch, bleed, or feel tender, but sometimes they’re completely painless. SCC most often appears on areas frequently exposed to UV radiation—like the face, ears, neck, scalp, hands, and lips—but it can also develop in less obvious places, including the mouth, genitals, and under the nails
（3）黑色素瘤皮膚癌：使用「A B C D E」口訣，去幫助自己快速初步診斷。A 代表形狀不對稱。例如兩半看起來截然不同。B 代表邊界不規則。呈不規則、鋸齒形或扇形邊界。C 代表顏色變化。多色或顏色不均的生長。D 代表直徑。大於約 6 毫米的痣的新生長。E 代表演化。隨著時間而發生的變化，例如痣的大小或顏色或形狀的變化。痣也可能演化出新的徵兆和症狀，包括發癢或出血。當然，還有其他比較少見的皮膚癌，例如T淋巴細胞皮膚癌， B淋巴細胞皮膚癌，轉移性皮膚癌等等，此處就不詳細討論了。總括來說，所有皮膚癌的初期症狀甚至乎後期症狀，有時候跟一粒普通的墨痣是沒有分別的。所以如果不肯定，務必找一位有經驗的醫生去做一個詳細的檢查，有需要的時候做一個皮膚切片化驗，以確定有沒有癌細胞。
（以下圖片就是黑色素瘤皮膚癌）
(3) Malignant Melanoma: signs and symptoms:
The ABCDE Rule
A – Asymmetry: One half of the mole doesn’t match the other.
B – Border: Edges are irregular, ragged, notched, or blurred.
C – Color: Uneven color with shades of brown, black, pink, red, white, or blue.
D – Diameter: Larger than 6 mm (about the size of a pencil eraser), though melanomas can be smaller.
E – Evolving: Any change in size, shape, color, or symptoms like itching or bleeding.
Other Warning Signs
A new mole or pigmented spot that looks different from others (the “ugly duckling” sign)
A sore that doesn’t heal
Spread of pigment from a mole into surrounding skin
Redness or swelling beyond the mole’s border
Changes in sensation—itching, tenderness, or pain
Changes in surface texture—scaliness, oozing, bleeding, or the appearance of a bump
Hidden Melanomas
Melanoma can also develop in less obvious places:
Under fingernails or toenails (as a dark streak)
On the palms, soles, or scalp
Inside the mouth, nose, genitals, or anus
總結：某些墨痣實為皮膚癌前兆，誤判可能導致病情惡化。只有具病理診斷訓練的醫生可識別、切片分析；非醫護人員操作反而延誤治療。
Conclusion: Early skin cancer often looks like a harmless mole. A qualified doctor trained in clinical dermatology can spot what beauty technicians miss—and save lives through timely intervention.