Nevoid basal cell carcinoma syndrome (NBCC) is an inherited syndrome characterized by multiple skin tumors and specific abnormalities associated with different body systems. The syndrome is caused by a defect in genes responsible for the Hedgehog signaling pathway, which leads to excessive proliferation of basal cell cells in the skin. The main manifestation of the syndrome is basal cell carcinomas, which can occur anywhere on the skin, but are especially common on the face, neck, and ear. In addition, patients may have other congenital anomalies, including bone malformations, eye abnormalities, and neurological disorders. Over time, the number and aggressiveness of tumors may increase, requiring a multidisciplinary approach to diagnosis and treatment.
History of the disease and interesting historical facts
Nevoid basal cell carcinoma syndrome was first described in the scientific literature in 1894, when dermatologists began investigating cases of multiple basal cell carcinomas. Since then, significant strides have been made in understanding its genetic basis and clinical manifestations. In the 1960s, the syndrome was named for its characteristic features, and in the 1980s, progress was made in identifying its genetic basis, particularly with the discovery of the role of the PTCH1 gene. This gene encodes a protein that is a key regulator of the Hedgehog pathway. Understanding the mechanism of this disease has led to the development of new diagnostic and therapeutic methods.
Epidemiology
Nevoid basal cell carcinoma syndrome occurs with a frequency of approximately 1 in 56,000 live births. However, this number may vary depending on the region and population. The disease has an autosomal dominant pattern of inheritance, which means that one copy of the mutated gene from one of the parents is enough for the syndrome to manifest. The prevalence of the syndrome is more pronounced in people with a family history of the disease, which confirms its hereditary component. According to studies, the diagnosis often appears in adolescence or young adulthood, but can also be found in middle-aged people.
Genetic predisposition to this disease
Nevoid basal cell carcinoma syndrome is associated with mutations in genes responsible for regulating the Hedgehog pathway. The most well-known of these are:
- PTCH1 (patch 1) is the main gene involved in the pathogenesis of the syndrome, encoding a receptor that inhibits signaling in the Hedgehog pathway.
- SUFU (suspended fungal unit) – is responsible for controlling the body's signals associated with PTCH1.
- SMO (smoothened) – encodes a protein that transmits a signal within the cell that activates the Hedgehog pathway.
It is known that about 80% cases of the syndrome are associated with mutations in the PTCH1 gene. Mutations can be either spontaneous or inherited, which contributes to the occurrence of multiple carcinomas in carriers. Familial cases of the disease are often reported in association with mutations in these genes, confirming their importance in genetic predisposition.
Risk factors for the development of this disease
Risk factors for the development of nevoid basal cell carcinoma syndrome can be divided into genetic and exogenous. Genetic factors include:
- Inheritance of a mutant gene from one of the parents.
- Having relatives diagnosed with the syndrome.
Exogenous factors may include:
- Ultraviolet radiation - increases the likelihood of developing skin tumors in patients with the syndrome.
- Systemic inflammatory skin diseases.
In addition, some studies suggest a possible role for chemical carcinogens such as arsenicum in increasing the risk of developing carcinomas in predisposed patients.
Diagnosis of this disease
Diagnosis of nevoid basal cell carcinoma syndrome is based on a combination of clinical observations, family history, and laboratory tests. The main symptoms include:
- Multiple basal cell carcinomas of the skin.
- Dental dysplasia and bone tissue lesions.
- Anomalies in the development of limbs.
Laboratory tests may include genetic testing for mutations in the PTCH1, SUFU, and SMO genes. Radiological examinations are performed to evaluate the skull and facial bones, as well as to detect possible cystic lesions in other organs.
Differential diagnosis includes exclusion of other dermatological diseases such as psoriasis, eczema and other forms of carcinoma.
Treatment
Treatment for nevoid basal cell carcinoma syndrome is multifaceted and depends on the severity and extent of the disease. Common treatment approaches include:
- Surgical removal of tumors is the standard treatment for removing skin carcinomas, especially when localized lesions are present.
- Pharmacological treatment – includes topical therapy using Hedgehog inhibitors such as vismodegib and immunotherapy.
- Laser therapy and cryotherapy – can be used for small and superficial lesions.
For advanced carcinomas, more aggressive approaches, including chemotherapy, may be recommended.
List of medications used to treat this disease
- Vizmed (vismodegib) is a Hedgehog pathway inhibitor.
- Squamous cell antibacterial antibiotic (eg, topical forms of mucopolysaccharides).
A combination of local agents can also be used to reduce the manifestations of the disease.
Disease monitoring
Monitoring of patients with nevoid basal cell carcinoma syndrome requires regular skin monitoring and early detection of relapses or new lesions. The prognosis is favorable in most cases with timely medical attention and proper treatment.
It is important to ensure adequate monitoring of the patient's condition, which includes:
- Regular check-ups with a dermatologist.
- Genetic counseling for patients and their families.
- Monitoring for potential complications such as metastatic disease.
Age-related features of the disease
Nevoid basal cell carcinoma syndrome can manifest at any age, but the first clinical symptoms usually occur in childhood or adolescence. In children, early skin manifestations may be observed, while in older patients, symptoms may be less pronounced. Older patients have an increased risk of developing more aggressive forms of carcinoma.
Questions and Answers
- What is nevoid basal cell carcinoma syndrome? Nevoid basal cell carcinoma syndrome is an inherited disorder characterized by multiple skin tumors and abnormalities associated with various body systems.
- What are the signs and symptoms of the syndrome? The main features of the syndrome are multiple basal cell carcinomas of the skin, as well as possible dental and bone abnormalities.
- How is the disease diagnosed? Diagnosis of the syndrome includes clinical examination, genetic testing, and radiological studies.
- What treatment is used for the syndrome? Treatment includes surgical removal of tumors, pharmacological therapy and intensive monitoring of the patient's condition.
- What is the outlook for a patient with this syndrome? With timely diagnosis and treatment, the prognosis can be favorable, but regular monitoring of the patient's condition is necessary.
