Key points for diagnosing skin cancer

The key points in diagnosing skin cancer are as follows:

1. Basal cell carcinoma

(1) It usually occurs after middle age.

(2) It is common in the head and face, including around the eye sockets, nose wings, nasolabial grooves, and cheeks.

(3) Based on clinical morphology, it is divided into five types: nodular ulcerative type, pigmented type, localized scleroderma, superficial type, and fibroepithelioma.

(4) Histopathological examination showed that the tumor parenchyma was mainly composed of basaloid cells. The tumor cells at the edge were arranged in a palisade pattern. There was a basement membrane zone between the tumor parenchyma and the stroma that was positive for PAS staining.

(5) It grows slowly but can be locally destroyed over time and rarely metastasizes.

2. Squamous cell carcinoma

(1) More common in men over 50 years old.

(2) It often occurs in exposed areas such as the head and face and the glans mucosa.

(3) The lesions initially appear as warty keratotic patches or light red or yellowish nodules, which break out after a few weeks or months to form ulcers with a hard base, raised borders, and a nipple- or cauliflower-like surface.

(4) It develops rapidly, is highly destructive, and often metastasizes.

(5) Histopathology shows epidermal acanthocytoma hyperplasia, with keratinized cells in the early stage and frequent nuclear division. The malignancy of the tumor is often estimated based on the depth of tumor cell infiltration, the number of keratinized cells and the number of atypical cells.

(6) Verrucous is a well-differentiated squamous cell carcinoma. It can be transformed from giant condyloma acuminatum or oral hyperplastic lesions, or it can spontaneously occur on the feet. It presents as pseudo-epithelioma-like hyperplasia with "sinus tracts" between the proliferating cells.

3. Bowen's disease

(1) The incidence rate in men and women is similar, and most cases occur after the age of 40.

(2) Mostly occurs on the trunk and buttocks.

(3) The lesions initially appear as light red or dark red papules with brown or skin-colored scabs on the surface. They gradually expand and often merge into plaques with clear edges. The scabs on the surface are not easy to peel off. If they are peeled off forcibly, a granular or nipple-like moist surface is exposed. Most lesions are single, and a few are multiple.

(4) 20%-30% may develop into invasive cancer, 2% may metastasize to local lymph nodes, and about half may develop concurrent cancers in other organs and parts of the body, with a poor prognosis.

(5) Histopathology showed that the epidermis lost its normal morphology and was replaced by atypical cell proliferation. The latter were larger and arranged in disorder. Giant tumor cells, heteronuclear division and individual dyskeratotic cells were also seen.

4. Paget's disease

(1) This disease is more common in middle-aged and elderly people.

(2) Breast Paget's disease is almost exclusively seen in the breasts of middle-aged and elderly women, with an average age of onset of 55 years. A small number of cases occur in the breasts of men. Extramammary Paget's disease can occur in both sexes, but is still more common in women, with an average age of onset later than that of breast Paget's disease.

(3) Paget's disease of the nipple occurs in the nipple and areola. Extramammary Paget's disease is common in areas where apocrine sweat glands are distributed, such as the vulva, male genitals, perianal area, and axilla.

(4) Eczematous patches occur on one side of the breast or in the apocrine gland distribution area, with clear borders and infiltration at the base. The course of the disease is slow and long-lasting, and the treatment for eczema is ineffective. This disease is suspected and can be confirmed by pathological biopsy.