Question 58

Squamous cell carcinoma primarily affects the stratum spinosum.

Squamous cell carcinoma is a type of skin cancer that originates from the keratinocytes found in the stratum spinosum, which is located above the stratum basale. This region is where the cells begin to differentiate and become more flattened, making it susceptible to malignant transformations.

A) Stratum basale

The stratum basale is the deepest layer of the epidermis and contains actively dividing cells that give rise to the cells in the upper layers. While this layer is important for skin regeneration, squamous cell carcinoma specifically arises from the keratinocytes in the stratum spinosum, not from the stratum basale.

B) Stratum spinosum

The stratum spinosum is the correct answer as it contains keratinocytes that are more mature and are the primary cells affected by squamous cell carcinoma. This layer is characterized by its spiky appearance due to desmosomal connections and is the site where malignant changes typically begin.

C) Stratum lucidum

The stratum lucidum is a thin, clear layer found only in certain areas of thick skin, such as the palms and soles. It is not involved in squamous cell carcinoma, as this type of cancer arises from the keratinocytes in the stratum spinosum, rather than the stratum lucidum.

D) Stratum granulosum

The stratum granulosum is a layer where keratinocytes begin to lose their nuclei and start the process of keratinization. While it plays a role in skin barrier function, squamous cell carcinoma does not originate in this layer, reinforcing that the stratum spinosum is the correct area affected by this type of cancer.

Conclusion

Squamous cell carcinoma is definitively linked to the stratum spinosum, where the conditions for malignant transformation of keratinocytes are present. Other options, such as the stratum basale, stratum lucidum, and stratum granulosum, do not represent the primary site of this type of cancer, thus confirming the stratum spinosum as the correct answer.