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Basosquamous Carcinoma of Skin

Last updated May 11, 2018

Approved by: Maulik P. Purohit MD, MPH

Basosquamous Carcinoma (BSC) of Skin is an uncommon, but very aggressive type of BCC that has squamous differentiation, when examined under the microscope.

What are the other Names for this Condition? (Also known as/Synonyms)

  • BSC of Skin
  • Metatypical Basal Cell Carcinoma of Skin
  • Metatypical Carcinoma

What is Basosquamous Carcinoma of Skin? (Definition/Background Information)

  • Basal Cell Carcinoma (BCC) of Skin is a malignant cancer affecting the skin. It is a slow-growing tumor generally observed in older individuals, in both men and women
  • This malignant carcinoma, which may be present as a lesion on the sun-exposed areas of the body, has the potential to metastasize (spread) to the lymph nodes
  • Basosquamous Carcinoma (BSC) of Skin is an uncommon, but very aggressive type of BCC that has squamous differentiation, when examined under the microscope. It is also known as Metatypical Basal Cell Carcinoma of Skin
  • BSC of Skin has a higher tendency to infiltrate into the adjoining soft tissues and nerves. They also depict a greater tendency to metastasize to distant regions compared to other types of Basal Cell Carcinomas
  • The cause of Basosquamous Carcinoma of Skin is unknown, but factors such as chronic sun exposure, smoking, and ionizing radiation, etc., are known to contribute towards its development. Also, fair-skinned Caucasians have a greater risk than dark-skinned Africans and Asians
  • Any combination of chemotherapy, radiation therapy, and invasive procedures (surgery) are used to treat Basosquamous Carcinoma of Skin. Small-sized tumors and tumors that have not metastasized can be cured through appropriate skin surgery
  • The prognosis for metastatic tumors depends upon many factors including the stage of the tumor, health status of the individual, and treatment response. The prognosis may be guarded

Who gets Basosquamous Carcinoma of Skin? (Age and Sex Distribution)

  • Basosquamous Carcinoma of Skin is an uncommon skin cancer that generally affects elderly or older adults; some cases may rarely develop in children too
  • It can occur in both males and females; however;
    • Among the older age group, males are affected more than females
    • In the younger age group, females are affected more than males, which may be attributed to their tendency to acquire sun-tanned bodies or visit skin tanning parlors more
  • This condition is observed worldwide across all racial and ethnic groups; however, lighter-skinned individuals (especially Caucasians) are more prone to BSC of Skin than darker-skinned individuals (such as Asians, Africans, etc.)

What are the Risk Factors for Basosquamous Carcinoma of Skin? (Predisposing Factors)

The risk factors that contribute to Basosquamous Carcinoma of Skin formation include:

  • Prolonged sun exposure, exposure to ultraviolet (UV) light
  • Use of tanning beds, tanning parlors
  • Arsenic exposure
  • Ionizing radiation
  • Smoking
  • The presence of certain genetic syndromes such as basal cell nevus syndrome (a rare autosomal dominant disorder) increases the risk
  • Caucasians are more vulnerable compared to other darker-toned individuals

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Basosquamous Carcinoma of Skin? (Etiology)

  • The exact cause of development of Basosquamous Carcinoma of Skin is not completely known, in a majority of cases
  • Although, genetic mutations have been detected in Basal Cell Carcinomas, which are currently being characterized
  • Most BCCs are sporadic in origin i.e., they occur in a random fashion

What are the Signs and Symptoms of Basosquamous Carcinoma of Skin?

Basosquamous Carcinoma of Skin signs and symptoms may include:

  • Basosquamous Carcinoma of Skin is a slow-growing, and generally an aggressive tumor. The tumor is a typical skin lesion, which has a papular and nodular appearance
  • The surface of the papule may be red, if intact. Else, it may appear as an ulcer, if the surface is eroded
  • It is typically observed on sun-exposed areas of the body; common sites include the head and neck region, arms and legs, etc.
  • The tumor may be solitary or many in number. In children, if it is associated with basal cell nevus syndrome, then multiple lesions may be observed
  • Some BSC of Skin may have pigmented appearance and may resemble a melanoma
  • Most lesions are less than 1-2 cm, but some may grow to larger sizes of even 10 cm
  • The lesion may grow and there may be itching sensation, ulceration, and bleeding

How is Basosquamous Carcinoma of Skin Diagnosed?

Some of the tests that may help in diagnosing Basosquamous Carcinoma of Skin include:

  • Complete physical examination with detailed medical history evaluation
  • Examination by a dermatologist using a dermoscopy, a special device to examine the skin
  • Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
  • Skin or tissue biopsy: A skin or tissue biopsy is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis
  • Differential diagnosis of other tumors should be ruled out; hence, biopsy is an important diagnostic tool

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Basosquamous Carcinoma of Skin?

The complications of Basosquamous Carcinoma of Skin could include:

  • If the tumor becomes big, develops into a firm mass and ulcerates, it can get secondarily infected with bacteria or fungus
  • This variety of BCC is more aggressive and shows a higher frequency of distant and regional metastasis. The tumor can also infiltrate into surrounding structures
  • BSC of Skin can cause cosmetic issues, since these skin tumors can cause large ulceration (termed rodent ulceration)
  • Recurrence of the tumor after a period of time; recurrence is frequently common with large tumors
  • Side effects of chemotherapy (such as toxicity) and radiation

How is Basosquamous Carcinoma of Skin Treated?

In general, the treatment of Basal Cell Carcinoma of Skin depends upon a variety of factors including:

  • The subtype of BCC
  • The location of the tumor
  • The number of tumors
  • The size of the tumor
  • Whether the tumor has metastasized

A combination of treatment methods may be used to treat Basosquamous Carcinoma of Skin. The type of surgery may include:

  • Shave biopsy of skin: This procedure is used for small tumors. There is no requirement of sutures (stitches) after the surgery
  • Excision of tumor: In this procedure, the tumor and surrounding tissue are removed with clear margins. Depending upon the amount of skin removed, surgical sutures may be necessary
  • Mohs surgery: In this procedure, the tumor is removed layer by layer precisely, until clear margins are achieved. Each layer removed is examined under a microscope through a ‘frozen section’ procedure, for the presence of residual tumor

In most cases, a surgical removal of the entire tumor is the preferred treatment option. This can result in a cure.

  • If the tumor has metastasized (in rare cases), then a combination of chemotherapy, radiation therapy, and invasive procedures may be used to treat the tumor
  • Targeted therapy medications are generally used for locally infiltrated or metastatic BCCs. This therapy destroys the tumor cells by acting against the proteins that are responsible for tumor growth
  • Large tumors that have infiltrated surrounding structures can be treated with radiation therapy (the use of high-energy beams to kill cancer cells)
  • Large tumors after complete skin excision may need skin grafting
  • Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals

Other techniques to treat this skin cancer (sometimes, when surgery may not be an option) may include:

  • Photodynamic therapy: In this procedure, a chemical cream is applied onto the tumor, which sensitizes the tumor to light (photosensitization). After the cream application, the tumor is exposed to light. This combination of chemical therapy and light therapy kills the tumor. Usually this technique results in good cosmetic outcomes
  • Cryotherapy: Here the tumor tissue is destroyed through a freezing technique. Typically liquid nitrogen is used to freeze the tumor
  • Topical creams, such as 5-fluorouracil cream and imiquimod cream, are two examples that can be used for topical treatment. These creams may be applied for several weeks, which slowly destroys the tumor

Note: If multiple lesions occur in children, then the possibility of basal cell nevus syndrome should be eliminated.

Generally, proper follow-up care with regular screening and check-ups are important and encouraged. In the case of large lesions, close follow-up and periodic observation is essential, since they have a tendency to recur.

How can Basosquamous Carcinoma of Skin be Prevented?

Currently, Basosquamous Carcinoma of Skin is a malignant skin cancer that has no preventive measures. However, the following factors may help reduce the risk for the condition:

  • Avoid or minimize sun exposure
  • Limit the use of tanning beds, tanning parlors
  • Smoking cessation
  • If it is caused by certain underlying disorders, then treating the underlying condition may help in the treatment and early cure of BSC of Skin
  • Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory, due to its metastasizing potential and high possibility of recurrence. Often several years of active vigilance is necessary

What is the Prognosis of Basosquamous Carcinoma of Skin? (Outcomes/Resolutions)

  • In general, the prognosis of Basosquamous Carcinoma is excellent, if it is detected and treated early. However, if it metastasizes to the local lymph nodes, the prognosis is guarded or unpredictable. Also, this subtype is the most aggressive form of Basal Cell Carcinoma
  • In such cases of metastatic BCC, its prognosis depends upon a set of several factors that include:
    • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
    • The surgical resectability of the tumor (meaning, if the tumor can be removed completely) 
    • Overall health of the individual: Individuals with overall excellent health have better prognosis compared to those with poor health
    • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
    • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have a poorer prognosis compared to tumors that do not recur
    • Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond so well to treatment
  • Without treatment (or with delayed treatment), Basosquamous Cell Carcinoma of Skin can metastasize and this may result in a poor prognosis
  • Close and regular follow-up and long-term monitor for recurrence of BCC has to be maintained

Additional and Relevant Useful Information for Basosquamous Carcinoma of Skin:

There are multiple types of Basal Cell Carcinoma of Skin:

  • Superficial Basal Cell Carcinoma of Skin
  • Nodular Basal Cell Carcinoma of Skin
  • Infiltrating Basal Cell Carcinoma of Skin
  • Micronodular Basal Cell Carcinoma of Skin
  • Fibroepithelial Basal Cell Carcinoma of Skin
  • Basal Cell Carcinoma of Skin with Adnexal Differentiation
  • Basosquamous Carcinoma of Skin
  • Keratotic Basal Cell Carcinoma of Skin

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Nov. 28, 2015
Last updated: May 11, 2018