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Primary Cutaneous Leiomyosarcoma

Last updated Jan. 1, 2019

Approved by: Maulik P. Purohit MD, MPH

Primary Cutaneous Leiomyosarcoma (PCL) is a highly-infrequent malignant tumor affecting the skin. Tumors with an origin in the dermis (of skin) are described as PCL tumors.

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

  • Dermal Leiomyosarcoma
  • Leiomyosarcoma of Skin
  • PCL (Primary Cutaneous Leiomyosarcoma)

What is Primary Cutaneous Leiomyosarcoma? (Definition/Background Information)

  • Leiomyosarcoma (LMS) is a rare type of connective tissue cancer, accounting for 5-10% of all soft tissue sarcomas (a type of cancer). It was once believed that leiomyosarcomas originated from small, benign, smooth muscle tumors, known as leiomyomas. The occurrence of a malignant tumor from a leiomyoma is now believed to be extremely rare
  • Primary Cutaneous Leiomyosarcoma (PCL) is a highly-infrequent malignant tumor affecting the skin. Tumors with an origin in the dermis (of skin) are described as PCL tumors
  • Normal skin is composed of 3 layers - the epidermis, the dermis, and the subcutis. When these malignancies arise from the subcutaneous skin tissues, they are called soft tissue leiomyosarcomas
  • Leiomyosarcoma occurs in the muscles that are not voluntarily controlled, known as smooth muscles. Due to the bounty of smooth muscle throughout the body, any individual is susceptible to LMS; although, the middle-aged and elderly adults are more prone to Primary Cutaneous Leiomyosarcoma
  • The signs and symptoms for Primary Cutaneous Leiomyosarcoma include the presence of a solitary tumor that may present pain and tenderness. Skin leiomyosarcomas are not frequently known to metastasize, although they may recur following surgery
  • Treatment for the condition is mainly through a wide surgical excision and tumor removal; supplementary therapies may be provided, if required. The prognosis of Primary Cutaneous Leiomyosarcoma depends a set of several factors, but in general, the prognosis is good with appropriate timely treatment

Who gets Primary Cutaneous Leiomyosarcoma? (Age and Sex Distribution)

  • Primary Cutaneous Leiomyosarcoma is an extremely rare malignancy; only around 150 cases have been reported in the medical literature
  • Typically, the tumor appears in adults (middle-age and older), with a peak incidence seen between the ages 50-60 years. PCL in children is an even rarer occurrence
  • In general, men are twice more likely to be affected than women
  • Individuals of all races and ethnicities are prone to Leiomyosarcoma of Skin, and there are no known geographical localizations

What are the Risk Factors for Primary Cutaneous Leiomyosarcoma? (Predisposing Factors)

While there are no well-established risk factors for Primary Cutaneous Leiomyosarcoma, there are a few leading theories behind LMS formation:

  • Trauma to the affected region
  • High-dose radiation exposure is believed to increase the risk for leiomyosarcoma formation
  • Certain inherited genetic traits are believed to increase the risk
  • Exposure to certain chemical agents, such as vinyl chloride, certain herbicides, and/or dioxins, may increase the risk
  • Immunocompromised patients infected by Epstein-Barr virus seem to be predisposed to LMS. The reason for this is not understood, yet there seems to be a definite correlation between the viral infection and the arising of multiple, synchronized leiomyosarcomas

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones 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 Primary Cutaneous Leiomyosarcoma? (Etiology)

Currently, there are no known causes for Primary Cutaneous Leiomyosarcoma.

  • As smooth muscles are found widely throughout the body, any individual is susceptible to LMS. However, due to the rarity of the cancer, it is difficult to determine what exactly leads to the formation of Cutaneous Leiomyosarcoma
  • Soft tissue leiomyosarcomas have exhibited certain genetic abnormalities

What are the Signs and Symptoms of Primary Cutaneous Leiomyosarcoma?

The signs and symptoms of Primary Cutaneous Leiomyosarcoma include:

  • It appears as a growing, usually painless nodule on skin; around 95% of the cases show the presence of a solitary tumor
  • Pain and tenderness may be present in some cases; pain may be felt on application of pressure on the tumor
  • The average tumor size is around 2 cm; the size range is mostly between 0.5-3.0 cm
  • LMS of Skin are poorly-circumscribed and firm tumors
  • Tumors generally form on hair-bearing skin surfaces
  • Most tumors are seen on the arms and legs; some have been described on the head (scalp), back, chest, and abdomen too

How is Primary Cutaneous Leiomyosarcoma Diagnosed?

A diagnosis of Primary Cutaneous Leiomyosarcoma may be undertaken using the following tools:

  • Complete physical examination and evaluation of medical (and family) history
  • Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
  • 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
  • Plain radiographs of the suspected skin area
  • An MRI scan of LMS can provide a view of the tumor’s effect on adjacent structures such as the nerves, bones, and other vascular structures
  • CT scans can help the physicians check for the presence of any metastasis to the adjacent regions
  • A biopsy may be necessary to determine, if the tumor present is a leiomyosarcoma, or a different soft tissue sarcoma. In the tissue biopsy procedure, the physician removes a sample of the tissue and sends it to the laboratory for a histopathological examination. The pathologist examines the biopsy under a microscope and arrives at a definitive diagnosis after a thorough evaluation of the clinical and microscopic findings, as well as by correlating the results of special studies on the tissues (if required)

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 possible Complications of Primary Cutaneous Leiomyosarcoma?

The complications of Primary Cutaneous Leiomyosarcoma may occur for a variety of reasons. These may include:

  • Metastasis of PCL: It is very rarely observed; much less than 1 in 10 cases are known to spread to other body regions, since these are superficial (on the skin surface) tumors
  • Local recurrence following surgery to remove the tumor

How is Primary Cutaneous Leiomyosarcoma Treated?

The treatment of Primary Cutaneous Leiomyosarcoma may differ from one individual to another. It depends on the tumor stage, tumor size, location, histological grade, and presence or absence of metastasis. Tumors are staged from I to IV, with IV being the most progressed, which has spread throughout the body.

  • Surgery is the most common treatment for leiomyosarcoma. Surgery aims to remove the tumor along with a portion of the tissue surrounding it (wide surgical excision). The surrounding tissue is removed to increase the likelihood of complete tumor removal, since some tumor cells may have drifted locally
  • Additional therapies: Other than surgery, LMS provides a treatment challenge due to the observed resistance to chemotherapy and radiation therapy

Once treatment is complete, it is recommended that the patient schedule regular check-ups, based on the recommendation of the specialist treating them. 

How can Primary Cutaneous Leiomyosarcoma be Prevented?

There are currently no known methods of preventing Primary Cutaneous Leiomyosarcoma.

What is the Prognosis of Primary Cutaneous Leiomyosarcoma? (Outcomes/Resolutions)

  • The prognosis of Primary Cutaneous Leiomyosarcoma depends on the stage of the malignancy upon diagnosis. However, in general, the prognosis with early detection/diagnosis and adequate surgical treatment is good
  • Spread of the tumor to other local and distant sites is very uncommon (some studies report a tumor metastasis rate between 1-10%). The tumor recurrence rate can be high; it varies between 5-50% according to some reports
  • Factors that may adversely affect the outcome include the following:
    • Tumors on toes and fingers
    • Size over 5 cm
    • Involvement of the subcutaneous tissues
    • Higher histological grade of the tumor
  • In general, the prognosis for leiomyosarcoma may depend upon a set of several factors that include:
    • The size of the tumor and the extent of its invasion: Individuals with small-sized tumors fare better than those with large-sized tumors
    • Stage of cancer: 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
    • Cell growth rate of the cancer (its ki-67 value): The ki-67 value is based on a protein found in cells that is a good indicator of how fast the tumor cells are growing. The ki-67 value is determined by a pathologist and is usually mentioned in the pathology report. Generally, much higher Ki-67 levels are seen in leiomyosarcomas than leiomyomas
    • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
    • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
    • Individuals with bulky disease have a poorer prognosis
    • Involvement of the regional lymph nodes, which can adversely affect the prognosis
    • Involvement of vital organs may complicate the condition
    • The surgical respectability of the tumor (meaning, if the tumor can be removed completely)
    • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse 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 to treatment
    • Progression of the condition makes the outcome worse
  • An early diagnosis and prompt treatment of the tumor generally yields better outcomes than a late diagnosis and delayed treatment

Additional and Relevant Useful Information for Primary Cutaneous Leiomyosarcoma:

Although leiomyosarcomas are rare cancer forms, there are many online discussion groups, local groups, and sarcoma centers available to provide help and support.

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: Feb. 7, 2017
Last updated: Jan. 1, 2019