What Is A Leiomyosarcoma?

What is a Leiomyosarcoma?

Leiomyosarcoma is a type of soft tissue sarcoma, which usually develops in blood vessels, muscle, and fat. Leiomyosarcoma is one of the common types of soft tissue sarcoma. Among superficial soft tissue neoplasms, sarcomas constitute less than 1% and, among them, leiomyosarcomas represent between 3 and 6.5%, according to different experts, which means that they are rare or infrequent tumors.

These neoplasms are derived from the muscular fibers of the hair erector muscle, from the muscle fibers located around the sweat glands or from the muscle fibers of the vascular tissue located at the junction between the dermis and the hypodermis. They tend to have a greater incidence in the average age of life, between 50 and 65 years of age, without prevalence by a particular gender.

From a clinical point of view, in the majority of cases the most frequent symptom is the presence of a painful nodular lesion that can be single or multiple. In the case of primary forms of leiomyosarcoma, the lesion is characteristically solitary or single, while the existence of multiple nodules must make consider the probability that it is a metastatic form or secondary to an internal leiomyosarcoma, a rare form, likewise, of manifesting itself as an internal neoplasia, and that in these cases almost 70% are located in the retroperitoneal and/or mesenteric zone. Thus, in some cases, and in a generic way, cutaneous metastases, even within the rarity, may constitute the first symptom or manifestation of the existence of a silent internal neoplasm.

These lesions are usually located in the lower limbs (50-70%), upper limbs (20-30%), and between these locations, they usually do so on the surfaces of extension and the proximal region of the limb, trunk (10-15%) and head (1-5%).

The diagnosis by the clinical examination of this type of lesion is exceptional, although there are differences in the clinical exploration between the cutaneous and subcutaneous nodules, being in almost all cases histopathological and immunohistochemical.

Clinically, cutaneous leiomyosarcomas usually present as nodules adhered to the skin in some cases ulcerated and with changes in coloration ranging from reddish, brown or even grayish-black, for example, and with slow growth. The subcutaneous leiomyosarcomas do not adhere, they are mobile and the skin is intact and without changes in color. The most frequent symptom of these tumors is pain (85 to 95% of cases), with less frequent symptoms such as pruritus (itching), burning or bleeding from the lesion. The differential diagnosis of leiomyosarcomas includes all those processes or conditions that manifest as soft tissue tumors and, as it is easy to assume, it basically goes through confirmation by histopathological study and includes, for example, fibrosarcomas, malignant histiocytomas, rhabdomyosarcomas, atypical or malignant fibroxanthomas, dermatofibromas, schwannomas, melanomas, neurofibromas, synovial sarcomas or cutaneous metastases, among others.

The division of the leiomyosarcomas, with histopathological criteria, in dermal or cutaneous and hypodermic or subcutaneous, is interesting from the prognostic-evolutionary point of view for the patient. Thus, in the case of cutaneous leiomyosarcomas, the local recurrence rate is 10 to 30% and that of metastasis is non-existent for some authors. The subcutaneous ones present a recurrence rate of 50 to 70% and metastasis between 30 and 40% of cases. Thus, primary cutaneous leiomyosarcoma, in contrast to the subcutaneous leiomyosarcoma, is a relatively benign disease, in relation to the vital prognosis and tumor recurrence with adequate treatment for these forms.

The diagnosis, given the aforementioned clinical characteristics, is based above all on the histopathological and immunohistochemical study.

The treatment is fundamentally surgical, performing an excision with safety margins, which according to most authors should be about 3 to 5 cm, given that it is a tumor with a poor response to radiotherapy and/or chemotherapy. Finally, it should be noted the importance of periodic clinical follow-up of these patients, given the rate of recurrence and the incidence of metastasis, as well as the prognostic importance of early detection of them.


The elapsed time between the diagnosis of the primary tumor and the development of skin lesions varies between 3 and 16 months. Cutaneous leiomyosarcomas are very exceptional. They can be primary or metastatic. The primary can be dermal; they have a very good prognosis, or hypodermic, of poor prognosis. The metastatic leiomyosarcomas to the skin are infrequent.

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Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:August 11, 2021

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