Testicular Leiomyosarcoma

Testicular leiomyosarcoma is an extremely rare cancer that develops from smooth muscle cells in or around the testicle, affecting primarily middle-aged and older men, though cases in younger individuals have been documented without any known risk factors.

Table of contents

• What is Testicular Leiomyosarcoma
• Who is Affected
• How It Presents
• Diagnosis and Testing
• Where the Tumor Develops
• Treatment Approaches
• Outlook and Behavior

What is Testicular Leiomyosarcoma

Testicular leiomyosarcoma is a rare type of cancer that develops from smooth muscle tissue in the testicular region. Leiomyosarcoma (a cancer arising from smooth muscle cells) represents one of the uncommon forms of soft tissue cancer that can affect the male reproductive system^[1]. This type of cancer belongs to a broader group called soft tissue sarcomas, which account for approximately 1% of all adult cancers^[3].

Primary testicular sarcomas are very rare growths that can arise either from a testicular teratoma or spermatocytic seminoma. These sarcomas generally behave indolently, meaning they grow slowly and have a rare potential for spreading to distant parts of the body, which typically results in a favorable outcome^[1].

Who is Affected

The average age at which people are diagnosed with primary testicular leiomyosarcoma is around 50 years^[1]. However, the disease has been reported across a wide age range. One case involved a 73-year-old patient^[2], while another affected a 27-year-old man^[1].

In younger individuals, these tumors have been reported in connection with certain risk factors including anabolic steroid use, testicular germ cell tumors, chronic inflammation of the testis, and testicular radiation therapy for treatment of leukemia^[1]. However, cases have also occurred in young men without any known predisposing factors^[1]. The disease can also develop in elderly patients without any prior exposure to these risk factors^[3].

Some patients have a history of previous procedures in the affected area, such as hydrocele repair (surgery to drain fluid around the testicle), though this connection is not clearly established^[2][3].

How It Presents

The most common way testicular leiomyosarcoma presents is as a painless, gradually enlarging mass in the scrotum. One patient experienced a painless, gradually enlarging left-sided scrotal swelling over six months^[1]. Another noticed an enlarging lump in the testicle that caused mild discomfort initially^[2].

The swelling typically appears hard and globular on examination. Patients generally do not experience constitutional symptoms such as weight loss, fatigue, or fever. There are usually no urologic symptoms or voiding complaints^[1][2].

In rare cases, testicular leiomyosarcoma can present in an unusual manner. One case was initially treated as epididymo-orchitis (inflammation of the testicle and epididymis) with antibiotics before the true diagnosis was discovered^[4].

Diagnosis and Testing

When a patient presents with a testicular mass, several tests are typically performed to determine the nature of the growth. An ultrasound examination of the scrotum is usually the first imaging test. This typically shows a hypoechoic (appearing darker on ultrasound) mass within the testicle, often with solid and cystic (fluid-filled) components^[1][3].

Blood tests are performed to measure tumor markers commonly elevated in testicular cancers. These include alpha-fetoprotein (AFP), beta human chorionic gonadotropin (β-HCG), and lactate dehydrogenase (LDH). In cases of leiomyosarcoma, these tumor markers are typically within normal ranges^[1][2][3].

Computed tomography (CT) scans of the chest, abdomen, and pelvis are performed to check for the spread of disease to other parts of the body. In early-stage cases, these scans do not reveal any evidence of metastatic deposits or enlarged lymph nodes^[1][2].

The definitive diagnosis is made after surgery by examining the tissue under a microscope and performing special staining tests. Microscopy typically shows a tumor composed of interlacing bundles and whorls of elongated spindle cells with eosinophilic (pink-staining) cytoplasm and hyperchromatic (darkly staining) nuclei. The presence of mitosis (dividing cells) is assessed, as higher numbers indicate more aggressive tumors^[4].

Immunohistochemistry (special staining to identify specific proteins) is essential for confirming the diagnosis. The tumor cells typically test positive for desmin, smooth muscle actin (SMA), and h-Caldesmon, which are markers of smooth muscle origin. They are usually negative for S-100 and CD117, which helps distinguish leiomyosarcoma from other types of tumors^[3][4].

Where the Tumor Develops

Leiomyosarcoma in the testicular region can originate from several different locations. It can arise from the testicular tunica (the covering of the testicle), the spermatic cord, the epididymis, or the dartos muscle and subcutaneous tissue of the scrotum^[5].

In the broader category of scrotal and paratesticular leiomyosarcomas, about 48% originate from the testicular tunica, 48% from the spermatic cord, 2% from the epididymis, and 2% from the dartos muscle or subcutaneous tissue of the scrotum^[5].

When leiomyosarcoma develops in the paratesticular region, it is divided into two types based on location: cutaneous leiomyosarcoma that originates from the arrector pili muscle of hair follicles or dartos muscle of genital skin, and subcutaneous leiomyosarcoma that originates from smooth muscle of genital organs or the vascular muscle layer of subcutaneous tissue^[9].

Treatment Approaches

The primary treatment for testicular leiomyosarcoma is surgical removal. When a testicular malignancy is suspected, patients undergo a procedure called high inguinal orchiectomy. This involves removing the affected testicle along with the spermatic cord through an incision in the groin. The high ligation of the spermatic cord is performed to ensure complete removal of potentially affected tissue^[1][2][3].

For paratesticular leiomyosarcomas, research analyzing 217 reported cases concluded that achieving a negative surgical margin (removing all visible tumor with a border of healthy tissue) is crucial for the best outcomes. Patients with tumors that had microscopic positive margins (cancer cells at the edge of removed tissue) had a significantly higher risk of local recurrence and distant spread compared to those with negative margins^[9].

The role of additional treatments after surgery depends on the specific circumstances. For subcutaneous leiomyosarcoma, high inguinal orchiectomy appears to be the optimal treatment strategy to achieve a negative surgical margin. For cutaneous leiomyosarcoma, the difference in outcomes between simple tumor removal and high inguinal orchiectomy may be less significant^[9].

According to available evidence, retroperitoneal lymph node removal, radiotherapy, and chemotherapy do not appear to have a clear role in the treatment of this type of cancer^[2]. Adjuvant radiation therapy (radiation given after surgery) has been suggested to reduce local recurrences in some cases^[12].

Following treatment, patients require regular surveillance with imaging scans. Leiomyosarcoma can recur many years after being in remission or showing no evidence of disease, making long-term monitoring essential^[4].

Outlook and Behavior

The behavior and outlook for testicular leiomyosarcoma vary depending on the grade and characteristics of the tumor. Low-grade tumors rarely recur or spread to other parts of the body, behave indolently, and have an overall excellent prognosis^[12].

High-grade tumors present a different picture. They can recur locally or spread to lymph nodes, lungs, or liver in about one-third of cases^[12]. One case report documented metastasis occurring eight months following high inguinal orchiectomy in a patient with high-grade disease^[4].

Research has identified several factors that influence prognosis. Patients with higher grade tumors have a significantly higher risk of distant metastasis and disease-specific mortality. Those with subcutaneous leiomyosarcoma tend to have slightly worse outcomes than those with cutaneous leiomyosarcoma^[9].

Most cases of primary testicular leiomyosarcoma reported in the literature indicate that this may be an indolent tumor with potential for cure if treated early^[4]. When leiomyosarcoma is identified early and removed by surgical excision, the prognosis can be good and full recovery quite likely. However, when the tumor is already large or has spread to other parts of the body, treatment is relatively more complex and the prognosis is poorer^[5].

Because of the rarity of this disease, there is a lack of data on the natural history, specific criteria for diagnosis, and standardized treatment recommendations. The long-term survival of men with paratesticular sarcomas is around 50%^[12].