| disease | Basal Cell Carcinoma |
| alias | Erosive Ulcer, Basal Cell Carcinoma |
Basal cell carcinoma, also known as rodent ulcer, is the most common type of skin cancer, with a very high incidence rate, ranking first among malignant tumors of the eyelid (accounting for over 50%). It is slightly more prevalent in males than females and more common in the elderly than in young people, with the peak age of occurrence between 50 and 60 years. Typically, it grows invasively only locally and rarely metastasizes. However, if improperly managed or left untreated, it can severely damage ocular tissues and even invade the paranasal sinuses and cranial cavity, leading to death.
bubble_chart Clinical Manifestations
The inner canthus is a common site of occurrence. In the early stages, the lesion often appears as a small, grade I raised translucent nodule. Flat lesions may resemble red patches or eczema, while pigmented ones resemble nevi, and raised surfaces may look like papillomas. The nodule is often surrounded by dilated blood vessels and covered with scabs or scales. It grows slowly and is prone to ulceration and bleeding when injured. The typical presentation is a shallow ulcer with a hard base and an irregular, undermined border, resembling a moth-eaten appearance, hence the name "rodent ulcer." The ulcer's edge becomes hard, raised, and rolled inward due to the downward proliferation of squamous epithelium in the skin at the ulcer margin. Reactive fibrous tissue proliferation is the histological basis for the hardening of the ulcer. The cancerous tissue infiltrates downward relatively slowly, and the infiltrating tumor nests typically stop at the same level, making the ulcer generally shallow. However, if the ulcer gradually spreads to surrounding tissues, it can cause extensive destruction, though it usually does not metastasize to distant sites. Injury or improper management can lead to cancer spread, accelerating progression, expanding the lesion, and causing it to lose its rodent ulcer appearance, potentially being mistaken for squamous cell carcinoma or melanoma. Early cases often have no subjective symptoms, but with injury or concurrent infection, they may cause recurrent bleeding, severe pain, and inflammatory enlargement of local lymph nodes. In severe cases, the lesion can destroy the eyelid, conjunctiva, and intraorbital tissues, invading the paranasal sinuses or cranial cavity.
Most patients are elderly individuals over the age of 50. The typical clinical presentation includes slow progression, an ulcer with a hard base and rolled edges, often accompanied by pigmentation at the margins. Diagnosis is not difficult for typical cases, but early-stage cases where an ulcer has not yet formed can be challenging. For elderly individuals, any transparent nodules near the eyelid margin, nevus-like, macula and papule-like, or papilloma-like small masses, surrounded by dilated blood vessels and with visible surface fissures, should raise suspicion.
bubble_chart Treatment Measures
Basal cell carcinoma is a low-grade malignant tumor. Early diagnosis and timely treatment can not only save the patient's life but also potentially preserve eyelid function and vision. Treatment options: Since basal cell carcinoma is sensitive to radiation therapy, deep X-ray radiation therapy should be administered. For basal cell carcinomas located far from the eyelid margin and involving a small area, radiation therapy alone may be sufficient for a cure. If the tumor is large, local excision combined with radiotherapy can yield good results. However, the excision area must be appropriately expanded to ensure complete removal of the cancerous tissue, as this cancer lacks a capsule and grows invasively beneath the skin, often extending beyond the visible surface. For advanced cases involving the eyeball and orbital tissues, orbital exenteration combined with radiation therapy is necessary. If the cancer has invaded the cranial cavity, chemotherapy should be performed.
Currently, due to advancements in treatment, the mortality rate of timely treated basal cell carcinoma has dropped to below 2%, with a favorable prognosis.
bubble_chart Differentiation
Differential diagnosis requires close attention to the combination of diseases and the characteristics of lesions at each developmental stage. For difficult cases, a biopsy is necessary to confirm the final diagnosis.
1. Differentiation from squamous cell carcinoma can be considered based on the following points:
⑴ Squamous cell carcinoma is more malignant and progresses faster than basal cell carcinoma. For lesions with a slow course, basal cell carcinoma should be considered first; conversely, for lesions with a short duration, rapid development, and cauliflower-like growth, squamous cell carcinoma should be prioritized.
⑵ In cases where both tumors present with ulcer formation, basal cell carcinoma ulcers are visually striking: they have a hard base, a shallow and flat ulcer bed, and irregular, rolled edges. In contrast, squamous cell carcinoma ulcers often vary in depth, have an uneven base, and exhibit fuller edges, sometimes even everted.
⑶ Basal cell carcinoma has a higher incidence of pigmentation compared to squamous cell carcinoma. For pigmented lesions, aside from melanoma, basal cell carcinoma should be considered first. The nodular surface of squamous cell carcinoma typically does not appear black due to the presence of large amounts of keratinized material.
⑷ Basal cell carcinoma rarely metastasizes, whereas squamous cell carcinoma can metastasize via lymphatic vessels to the preauricular and submandibular lymph nodes. Therefore, the presence of lymph node metastasis suggests squamous cell carcinoma.
2. Differentiation from malignant melanoma: Malignant melanoma has a shorter disease course and progresses more rapidly. Pigmentation is diffuse around the lesion, with vascular engorgement, and it can develop into a massive tumor within a short time. Fine cracks appear on the surface, and bloody discharge occurs even when the lesion is very small.
