Histopathology of squamous-cell carcinoma

Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the lining of the respiratory and digestive tracts. Common types include: *

Squamous-cell skin cancer Squamous-cell skin cancer, also known as cutaneous squamous-cell carcinoma (cSCC), is one of the main types of skin cancer along with basal cell cancer and melanoma. It usually presents as a hard lump with a scaly top but can also form an ulcer. O ...

: A type of skin cancer * Squamous-cell carcinoma of the lung: A type of lung cancer *

Squamous-cell thyroid carcinoma Squamous-cell thyroid carcinoma is rare malignant neoplasm of thyroid gland which shows tumor cells with distinct squamous differentiation. The incidence of SCTC is less than 1% out of thyroid malignancies. Pathophysiology Squamous epithelial ...

: A type of thyroid cancer *

Esophageal squamous-cell carcinoma Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include difficulty in swallowing and weight loss. Other symptoms may include pain when swallowing, a hoarse voice ...

: A type of

esophageal cancer Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include difficulty in swallowing and weight loss. Other symptoms may include pain when swallowing, a hoarse voice ...

* Squamous-cell carcinoma of the vagina: A type of vaginal cancer Despite sharing the name "squamous-cell carcinoma", the SCCs of different body sites can show differences in their presented

symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

s, natural history,

prognosis Prognosis (Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain stabl ...

, and response to treatment.

By body location

Human papillomavirus infection has been associated with SCCs of the oropharynx, lung, fingers, and anogenital region.

Head and neck cancer

About 90% of cases of head and neck cancer (cancer of the mouth, nasal cavity, nasopharynx, throat and associated structures) are due to SCC.

Skin

Squamous cell carcinoma of the skin is the second most common skin cancer, accounting for over 1 million cases in the United States each year.

Thyroid

Primary squamous-cell thyroid carcinoma shows an aggressive biological phenotype resulting in poor prognosis for patients.

Esophagus

Esophageal cancer Esophageal cancer is cancer arising from the esophagus—the food pipe that runs between the throat and the stomach. Symptoms often include difficulty in swallowing and weight loss. Other symptoms may include pain when swallowing, a hoarse voice ...

may be due to either esophageal squamous cell carcinoma (ESCC) or

adenocarcinoma Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ) (AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or ...

(EAC). SCCs tend to occur closer to the mouth, while adenocarcinomas occur closer to the stomach. Dysphagia (difficulty swallowing, solids worse than liquids) and painful swallowing are common initial symptoms. If the disease is localized, surgical removal of the affected esophagus may offer the possibility of a cure. If the disease has spread, chemotherapy and radiotherapy are commonly used.

Lung

When associated with the lung, it is typically a centrally located large-cell cancer (nonsmall-cell lung cancer). It often has a

paraneoplastic syndrome A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of a tumor in the body (usually a cancerous one), specifically due to the production of chemical signaling molecules (such as hormones or cytokines) by ...

causing ectopic production of parathyroid hormone-related protein, resulting in

hypercalcemia Hypercalcemia, also spelled hypercalcaemia, is a high calcium (Ca2+) level in the blood serum. The normal range is 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), with levels greater than 2.6 mmol/L defined as hypercalcemi ...

, but paraneoplastic syndrome is more commonly associated with small-cell lung cancer. It is primarily due to smoking.

Penis

Human papillomavirus (HPV), primarily HPV 16 and 18, are strongly implicated in the development of SCC of the penis. Three carcinomas ''in situ'' are associated with SCCs of the penis: # Bowen's disease presents as leukoplakia on the shaft. Around a third of cases progress to SCC. #

Erythroplasia of Queyrat Squamous-cell skin cancer, also known as cutaneous squamous-cell carcinoma (cSCC), is one of the main types of skin cancer along with basal cell cancer and melanoma. It usually presents as a hard lump with a scaly top but can also form an ulcer. O ...

, a variation of Bowen's disease, presents as erythroplakia on the glans. # Bowenoid papulosis, which histologically resembles Bowen disease, presents as reddish papules.

Prostate

When associated with the prostate, squamous-cell carcinoma is very aggressive in nature. It is difficult to detect as no increase in prostate-specific antigen levels is seen, meaning that the cancer is often diagnosed at an advanced stage.

Vagina and cervix

Vaginal SCC spreads slowly and usually stays near the vagina, but may spread to the lungs and liver. This is the most common type of vaginal cancer.

Bladder

Most bladder cancer is transitional cell, but bladder cancer associated with

schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody s ...

is often SCC.

Diagnosis

Oral cancer (1) squamous cell carcinoma histopathology

Cytopathology of nonkeratinizing squamous cell carcinoma

Medical history, physical examination and

medical imaging Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to rev ...

may suggest a squamous cell carcinoma, but a biopsy for

histopathology Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία '' -logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Spe ...

generally establishes the diagnosis. TP63 staining is the main histological marker for Squamous cell carcinoma. In addition, TP63 is an essential transcription factor to establish squamous cell identity. File:Squamous Cell Carcinoma well differentiated Left upper paraspinal back with adjacent actinic keratosis.jpg, Squamous cell carcinoma, well differentiated, left upper paraspinal back marked for biopsy with adjacent actinic keratosis File:Squamous Cell Carcinoma Left Lateral Canthus.jpg, Squamous cell carcinoma, left lateral canthus marked for biopsy File:Squamous Cell Carcinoma Left Ventral Forearm.jpg, Squamous cell carcinoma, left ventral forearm

Classification

Cancer can be considered a very large and exceptionally heterogeneous family of malignant diseases, with squamous cell carcinomas comprising one of the largest subsets. All SCC lesions are thought to begin via the repeated, uncontrolled division of cancer stem cells of epithelial lineage or characteristics. SCCs arise from squamous cells, which are flat cells that line many areas of the body. Some of which are keratinocytes. Accumulation of these cancer cells causes a microscopic focus of abnormal cells that are, at least initially, locally confined within the specific tissue in which the progenitor cell resided. This condition is called squamous cell carcinoma ''in situ'', and it is diagnosed when the tumor has not yet penetrated the

basement membrane The basement membrane is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between Epithelium, epithelial tissues including mesot ...

or other delimiting structure to invade adjacent tissues. Once the lesion has grown and progressed to the point where it has breached, penetrated, and infiltrated adjacent structures, it is referred to as "

invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer ...

" squamous cell carcinoma. Once a carcinoma becomes invasive, it is able to spread to other organs and cause the formation of a metastasis, or "secondary tumor".

Tissue of origin

The International Classification of Diseases for Oncology (ICD-O) system lists a number of morphological subtypes and variants of malignant squamous cell neoplasms, including: * Papillary thyroid carcinoma (code 8050/3) * Verrucous squamous cell carcinoma (code 8051/3) * Papillary squamous cell carcinoma (code 8052/3) * Squamous cell carcinoma (code 8070/3) * Large-cell keratinizing squamous cell carcinoma (code 8071/3) * Large-cell nonkeratinizing squamous cell carcinoma (code 8072/3) * Small-cell keratinizing squamous cell carcinoma (code 8073/3) * Spindle-cell squamous cell carcinoma (code 8074/3) It is also known as spindle-cell carcinoma, and is a subtype characterized by spindle-shaped atypical cells. * Adenoid/pseudoglandular squamous cell carcinoma (code 8075/3) * Intraepidermal squamous cell carcinoma (code 8081/3) * Lymphoepithelial carcinoma (code 8082/3) Other variants of SCCs are recognized under other systems, such as keratoacanthoma.

Other histopathologic subtypes

Marjolin's ulcer Marjolin's ulcer refers to an aggressive ulcerating squamous cell carcinoma presenting in an area of previously traumatized, chronically inflamed, or scarred skin.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed ...

is a type of SCC that arises from a nonhealing ulcer or burn wound. More recent evidence, however, suggests that genetic differences exist between SCC and

, which were previously underappreciated. One method of classifying squamous cell carcinomas is by their appearance under microscope. Subtypes may include: * Adenoid squamous cell carcinoma (also known as pseudoglandular squamous cell carcinoma) is characterized by a tubular microscopic pattern and keratinocyte acantholysis. * Basaloid squamous cell carcinoma is characterized by a predilection for the tongue base. * Clear-cell squamous cell carcinoma (also known as clear-cell carcinoma of the skin) is characterized by keratinocytes that appear clear as a result of hydropic swelling. * Signet ring-cell squamous cell carcinoma (occasionally rendered as signet ring-cell squamous cell carcinoma) is a histological variant characterized by concentric rings composed of keratin and large vacuoles corresponding to markedly dilated

endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...

. These vacuoles grow to such an extent that they radically displace the cell nucleus toward the cell membrane, giving the cell a distinctive superficial resemblance to a "signet ring" when viewed under a microscope. File:SkinTumors-P6070232.JPG, Adenoid squamous-cell carcinoma File:SkinTumors-P6020140.JPG, Basaloid squamous-cell carcinoma File:SkinTumors-P5290109.JPG, Clear-cell squamous-cell carcinoma File:SkinTumors-P5300131.JPG, Spindle-cell squamous-cell carcinoma

Prevention

Studies have found evidences for an association between diet and skin cancers, including SCC. The consumption of high-fat dairy foods increases SCC tumor risk in people with previous skin cancer. Green leafy vegetables may help prevent development of subsequent SCC and multiple studies found that raw vegetables and fruits are significantly protective against SCC risk. On the other hand, consumption of whole milk, yogurt, and cheese may increase SCC risk in susceptible people. In addition, meat and fat dietary pattern can increase the risk of SCC in people without a history of SCC, but the association is again more prominent in people with a history of skin cancer. Tobacco smoking and a dietary pattern characterized by high beer and liquor intake also increase the risk of SCC significantly.

References

{{Authority control Cancer Oncology Epithelium