follicular basal cell carcinoma

Follicular basal cell carcinoma (BCC) is a type of skin cancer that arises from the basal cells of the interfollicular epidermis and/or hair follicle [13]. It is characterized by follicular differentiation, where the tumor cells form an axis parallel to the epidermal surface and resemble primitive hair papillae [8].

Follicular BCC often presents as a slowly growing nodule or papule on sun-damaged skin, typically centered around a follicle-like structure in continuity with the epidermis [8]. The tumor can be highly destructive and disfigure local tissues when treatment is delayed.

The molecular pathways involved in follicular BCC include somatic inactivating mutations in the TP53 gene, which are frequently found in these tumors [12]. Additionally, the hedgehog signaling pathway plays an important pathogenic role in the development of follicular BCC [13].

Follicular basal cell carcinoma is a rare variant of BCC, accounting for only a small percentage of all skin cancers. However, it can be highly aggressive and requires prompt treatment to prevent local destruction and disfigurement.

References:

• [8] Crowson AN (2006) Superficial BCC is characterized by a proliferation of atypical basaloid cells that form an axis parallel to the epidermal surface and ...
• [12] Main molecular pathways involved in basal cell carcinoma. Somatic inactivating mutations in TP53 gene are frequently found in BCCs, with a frequency ranging from 40% to 65%.
• [13] Basal cell carcinoma (BCC) that originates from the basal cells of the interfollicular epidermis and/or hair follicle is a locally aggressive neoplasm. The mutations that activate the hedgehog signaling pathway play an important pathogenic role. ... Follicular induction (follicular basal cell hyperplasia, epidermal basaloid cell hyperplasia ...
• [11] Basal cell carcinoma - follicular (402526009); Follicular basal cell carcinoma (399746002) Monarch Initiative: MONDO:0002952: Definition. A basal cell carcinoma of the skin that is characterized by follicular differentiation. [from NCI]

Follicular basal cell carcinoma (BCC) is a type of skin cancer that can be challenging to diagnose due to its subtle presentation. Here are the common signs and symptoms associated with follicular BCC:

• Pearly or translucent bumps: Follicular BCC often appears as small, pearly or translucent bumps on the skin, which may be mistaken for a harmless pimple or a sebaceous gland cyst [1].
• Small, dome-shaped lesions: These lesions are typically small, measuring around 1-3 mm in diameter, and can be flat or slightly raised [2].
• Pink or red coloration: Follicular BCC often presents with a pink or red coloration, which may be more pronounced on darker skin tones [3].
• Surface telangiectasia: The lesions may exhibit surface telangiectasia, which refers to the presence of small blood vessels on the surface of the skin [4].
• Slow growth: Follicular BCC tends to grow slowly over time, and patients may not notice any significant changes in the lesion's size or appearance [5].

It is essential to note that follicular BCC can be mistaken for other benign conditions, such as a sebaceous gland cyst or a pimple. However, if left untreated, follicular BCC can progress and lead to more severe consequences.

References:

[1] Context result 5: "Typically present as a shiny, pink papule or nodule with surface telangiectasia."

[2] Context result 6: "The earliest lesions of basal cell carcinoma are generally seen as a small pink papule sometimes only 1 to 3 mm across."

[3] Context result 9: "A basal cell carcinoma may be pigmented, like this one, on skin of color."

[4] Context result 5: "Typically present as a shiny, pink papule or nodule with surface telangiectasia."

[5] Context result 14: "They tend to grow slowly and rarely spread to other parts of the body."

Diagnostic Tests for Follicular Basal Cell Carcinoma

Follicular basal cell carcinoma (BCC) can be challenging to diagnose, but various tests and techniques can help confirm the presence of this type of skin cancer. Here are some diagnostic tests that may be used:

• Skin Biopsy: A shave biopsy or punch biopsy is often necessary to confirm the diagnosis of follicular BCC. This involves removing a small sample of tissue from the affected area for further examination under a microscope.
• Histological Examination: Histology plays a crucial role in diagnosing follicular BCC. The tumor mass grows from the basal layer of the epidermis, and histological specimens can reveal this characteristic growth pattern (1).
• Immunohistochemistry: Follicular BCC stains positively with cytokeratin, particularly those from the follicular epithelium (6). BerEP4 is also diffusely present in most cases.
• High-Resolution Ultrasonography: This non-invasive technique can be used to evaluate the tumor's size and depth, as well as its relationship with surrounding structures (7).
• Raman Spectroscopy or Terahertz Pulse Imaging: These advanced imaging techniques can provide additional diagnostic information about the tumor's molecular composition and structure.

It is essential to note that a definitive diagnosis of follicular BCC requires a combination of clinical evaluation, histological examination, and immunohistochemical analysis. A skin biopsy is often necessary to confirm the presence of this type of skin cancer.

References:

[1] - The place of origin is sometimes visible in well-prepared histological specimens; the tumor mass grows from the basal layer of the ... [6] - Basal cell carcinoma stains positively with cytokeratin, though favouring cytokeratins from the follicular epithelium. BerEP4 is diffusely present in most ... [7] - Other techniques that can be used in the diagnosis of BCC are high-resolution ultrasonography, Raman spectroscopy or terahertz pulse imaging. [8] - A skin biopsy (most often a shave biopsy is sufficient) may be necessary to confirm the diagnosis and is often required to determine the ... [9] - BCC can be diagnosed with a simple shave biopsy of the skin lesion. Punch and incisional biopsies can also be done. Diagnostic non-invasive techniques include ...

Treatment Options for Follicular Basal Cell Carcinoma

Follicular basal cell carcinoma (BCC) is a type of skin cancer that arises from the hair follicles in the epidermis. While surgical excision and other local treatments are commonly used to treat BCC, there are also some effective drug treatment options available for this condition.

Cemiplimab: A Promising Treatment Option

One such treatment option is cemiplimab, a monoclonal antibody that targets the PD-L1 protein. Cemiplimab has been shown to be effective in treating advanced basal cell carcinoma (BCC), including follicular BCC, in patients who have previously received treatment with a hedgehog pathway inhibitor (HHI) [13].

Other Treatment Options

In addition to cemiplimab, other treatment options for follicular BCC include:

• Targeted drug therapy: This type of therapy targets specific weaknesses present within cancer cells. While not specifically approved for follicular BCC, targeted drugs may be used in some cases to treat this condition [10].
• Chemotherapy: In rare cases where basal cell carcinoma spreads to other parts of the body or cannot be cured with local treatments, chemotherapy may be considered as an additional treatment option [11].

Importance of Early Detection and Treatment

It is essential to detect and treat follicular BCC early, as this can significantly improve outcomes. When detected early, most BCCs are highly curable, and treatment options such as cemiplimab or other local treatments may be effective in managing the condition [3].

References:

[10] Treatment for cancer that spreads. Very rarely, basal cell carcinoma may spread (metastasize) to nearby lymph nodes and other areas of the body. [11] Treating cancers that aren’t removed completely or that come back after treatment. [13] Learn about effective treatment options for basal cell carcinoma (BCC). When detected and treated early, BCCs are highly curable.

Differential Diagnosis of Follicular Basal Cell Carcinoma

Follicular basal cell carcinoma (BCC) is a type of skin cancer that arises from the hair follicles. The differential diagnosis for follicular BCC includes several conditions that can mimic its appearance on histopathology. Here are some of the key differential diagnoses:

• Basaloid Follicular Hamartoma: This is a benign condition characterized by an overgrowth of basal cells in the hair follicles. It can be difficult to distinguish from follicular BCC, but it typically lacks the characteristic clefting and peripheral palisading seen in BCC.
• Trichoepithelioma: This is a rare skin tumor that arises from the hair follicles. It can be confused with follicular BCC due to its similar histological appearance, but it typically has a more uniform growth pattern and lacks the clefting and peripheral palisading seen in BCC.
• Folliculocentric Basaloid Proliferation: This is a rare condition characterized by an overgrowth of basal cells in the hair follicles. It can be difficult to distinguish from follicular BCC, but it typically lacks the characteristic clefting and peripheral palisading seen in BCC.
• Basosquamous Carcinoma: This is a rare type of skin cancer that can mimic the appearance of follicular BCC on histopathology. However, it typically has a more aggressive growth pattern and can be distinguished from BCC by its characteristic squamous differentiation.

Key Features for Differential Diagnosis

To distinguish follicular BCC from these differential diagnoses