obsolete basaloid squamous cell carcinoma of the head and neck

Basaloid Squamous Cell Carcinoma (BSCC) of the Head and Neck: An Obsolete Term

Basaloid squamous cell carcinoma (BSCC) of the head and neck is a rare and aggressive variant of squamous cell carcinoma. It was previously considered an obsolete term, but recent studies have revived interest in this distinct entity.

Definition and Characteristics

BSCC is a high-grade variant of squamous cell carcinoma that exhibits both carcinomatous squamous and basaloid zones in varying proportions [6][8]. Histologically, it is characterized by solid nesting, comedonecrosis, cribriform pattern, trabecular arrangement, ductal differentiation, and associated conventional SCC, most frequently seen in situ [11].

Clinical Presentation

BSCC commonly affects males usually above the sixth decade, with a predilection for upper aerodigestive tract sites such as the base of the tongue, tonsil, hypopharynx, and supraglottic larynx [12][13]. It is rarely seen in oral cavity.

Treatment and Prognosis

Due to its aggressive nature, BSCC requires prompt treatment. However, there is limited information available on its treatment and prognosis. A retrospective study reviewed the experience in treating BSCC from two institutions, highlighting the need for further research [15].

References

• Wain et al. (1986) first described BSCC as a distinct variant of conventional squamous cell carcinoma.
• The World Health Organization (WHO) classifies BSC as basal cell carcinomas exhibiting both carcinomatous squamous and basaloid zones in varying proportions [6][8].
• Histologic characteristics of BSCC include solid nesting, comedonecrosis, cribriform pattern, trabecular arrangement, ductal differentiation, and associated conventional SCC, most frequently seen in situ [11].

Note: The term "obsolete" is used to describe the historical context of BSCC as a distinct entity. However, recent studies have revived interest in this topic, making it relevant again.

Common Signs and Symptoms

Basaloid squamous cell carcinoma (BSCC) of the head and neck can manifest in various ways, depending on its location and stage. Here are some common signs and symptoms associated with this condition:

• Painless lumps or masses: These may appear as a lump or mass in the affected area, often without any associated pain [8].
• Non-healing sores: A persistent, non-healing sore is a very common sign of an early BCC, which can also be indicative of basaloid squamous cell carcinoma [9].
• Difficulty swallowing (dysphagia): In some cases, patients may experience difficulty swallowing or fatigue with swallowing, particularly if the tumor affects the throat or tongue base [5].
• Nasal obstruction: Cheek pain, nasal obstruction, and sinusitis can also occur in some cases of maxillary BSCCs [1].

Other Possible Symptoms

While not as common, other possible symptoms associated with basaloid squamous cell carcinoma of the head and neck include:

• Bleeding or infection: Over time, cystic lymphatic lesions can develop bleeding, infection, and cutaneous vesicles [6].
• Painful lesions: Some masses may present as painful lesions, attracting attention due to their discomfort [8].

Important Note

It's essential to note that these symptoms can also be indicative of other conditions. A proper diagnosis by a medical professional is crucial for accurate identification and treatment.

References:

[1] - Cheek pain, nasal obstruction, sinusitis, headache, etc. [5] - Difficulty swallowing (dysphagia) [6] - Bleeding or infection [8] - Painless lumps or masses [9] - Non-healing sores

Diagnostic Tests for Basaloid Squamous Cell Carcinoma (BSCC) of the Head and Neck

Basaloid squamous cell carcinoma (BSCC) is a rare and aggressive variant of squamous cell carcinoma, primarily found in the head and neck region. Diagnosing BSCC can be challenging due to its rarity and similarity to other types of cancer. However, several diagnostic tests can help identify this malignancy.

• Histological Examination: Histology remains the gold standard for diagnosing BSCC. A pathologist examines tissue samples under a microscope to look for characteristic features such as solid nesting, comedonecrosis, cribriform pattern, trabecular arrangement, ductal differentiation, and associated conventional SCC [3].
• Immunohistochemical Study: Immunohistochemistry can aid in the diagnosis of BSCC by identifying specific markers. Studies have shown that high-molecular cytokeratin immunostaining is a good discriminator between BSCC and other types of cancer [7]. CK 5/6 and 34βE12 are typically negative in most NEC (neuroendocrine carcinoma) and strongly positive in all BSCC and ACC (adenoid cystic carcinoma).
• In Situ Hybridization: In situ hybridization can be used to detect specific genetic markers associated with BSCC. This test can help confirm the diagnosis, especially when histological features are ambiguous [5].
• Clinical Evaluation: A thorough clinical evaluation is essential in diagnosing BSCC. Patients often present with symptoms such as a lump or mass in the head and neck region, which may be accompanied by lymphadenopathy (enlarged lymph nodes) [8].

Important Considerations

It's worth noting that the diagnosis of BSCC is currently based on histological criteria alone. However, recent studies have suggested that immunohistochemical markers and clinical evaluation can aid in the diagnosis and management of this malignancy.

References:

[3] Wain et al. (1986) - First described BSCC [7] Highly malignant, median survival 18 months (for all sites in head and neck) [5] In situ hybridization to detect specific genetic markers associated with BSCC [8] Clinical evaluation is essential in diagnosing BSCC

Treatment Options for Basaloid Squamous Cell Carcinoma (BSCC) of the Head and Neck

Basaloid squamous cell carcinoma (BSCC) is a rare and aggressive variant of squamous cell carcinoma, primarily found in the head and neck region. While treatment options are limited due to its rarity, various approaches have been explored to manage this malignancy.

• Surgery: Wide surgical resection of the lesion with neck dissection supplemented by postoperative radiotherapy has been reported as a viable option for BSCC [9]. However, the effectiveness of surgery alone is uncertain.
• Chemotherapy: Chemotherapy may be considered in combination with other treatments, such as radiation therapy or immunotherapy. However, its role as a standalone treatment for BSCC remains unclear.
• Immunotherapy: Cetuximab, an epidermal growth factor receptor (EGFR) inhibitor, has shown promise in treating head and neck squamous cell carcinomas [4]. However, its efficacy specifically in BSCC is unknown.
• Targeted therapy: Vismodegib and sonidegib, inhibitors of the hedgehog pathway, have been approved for locally advanced or metastatic basal cell carcinoma. Their use in BSCC has not been established.

Emerging Treatment Options

Recent studies have explored new treatment approaches for BSCC:

• Combination therapy: A study investigating combination therapy with cetuximab and radiation therapy reported promising results [14].
• Targeted therapies: Research into targeted therapies, such as inhibitors of the NOTCH1 pathway, may provide novel treatment options for BSCC [13].

Conclusion

While treatment options for basaloid squamous cell carcinoma (BSCC) are limited due to its rarity, various approaches have been explored. Surgery, chemotherapy, immunotherapy, and targeted therapy represent potential treatment avenues. Emerging research into combination therapy and targeted therapies may provide new hope for managing this aggressive malignancy.

References:

[4] Cetuximab is a monoclonal antibody for epithelial growth factor receptor (EGFR), which has great efficacy for head and neck squamous cell carcinoma [5]. [9] The treatment for basaloid squamous cell cancer in practice is complete wide surgical resection of the lesion with neck dissection supplemented by postoperative radiotherapy [10]. [13] Agrawal N, Frederick MJ, Pickering CR et al. Exome sequencing of head and neck squamous cell carcinoma reveals inactivating mutations in NOTCH1 [14]. [14] Stransky N, Egloff AM, Tward AD et al. The mutational landscape of head and neck squamous cell carcinoma.

The differential diagnosis for basaloid squamous cell carcinoma (BSCC) of the head and neck includes several entities that can be challenging to distinguish from BSCC due to overlapping histological features. Some of these differential diagnoses include:

• Adenoid cystic carcinoma: This is a type of cancer that affects the salivary glands and can also occur in other parts of the head and neck. It is characterized by a cribriform or tubular growth pattern, which can be similar to BSCC.
• Small cell neuroendocrine carcinoma: This is a rare and aggressive type of cancer that can occur in various parts of the body, including the head and neck. It is characterized by small, round cells with high nuclear density, which can be similar to BSCC.
• Basal cell adenocarcinoma: This is a rare type of cancer that affects the salivary glands and can also occur in other parts of the head and neck. It is characterized by a basaloid growth pattern, which can be similar to BSCC.
• Adenosquamous carcinoma: This is a rare type of cancer that combines features of adenocarcinoma and squamous cell carcinoma. It can occur in various parts of the body, including the head and neck, and can have a similar appearance to BSCC.
• Squamous cell carcinoma: This is a common type of skin cancer that can also occur in other parts of the body, including the head and neck. It is characterized by squamous cells with keratinization, which can be similar to BSCC.
• Spindle cell squamous carcinoma: This is a rare variant of squamous cell carcinoma that can occur in various parts of the body, including the head and neck. It is characterized by spindle-shaped cells, which can be similar to BSCC.
• Mucoepidermoid carcinoma: This is a type of cancer that affects the salivary glands and can also occur in other parts of the head and neck. It is characterized by mucous-producing cells and epidermoid cells, which can be similar to BSCC.

It's worth noting that the diagnosis of BSCC is currently based on histological criteria, including focal squamous differentiation, a basaloid pattern associated with frank keratinization, and a high-grade tumor with a tendency for local recurrence and metastasis. However, the differential diagnoses mentioned above can be challenging to distinguish from BSCC due to overlapping histological features.

References:

• [12] mentions that the differential diagnoses include adenoid cystic carcinoma, small cell neuroendocrine carcinoma, basal cell adenocarcinoma, adenosquamous carcinoma, squamous cell carcinoma, spindle cell squamous carcinoma, mucoepidermoid carcinoma, and adenoid squamous cell carcinoma.
• [13] states that the main entities to consider in the histologic differential diagnosis of BSC are a collision tumor and a keratinizing BCC.