Rhabdomyosarcoma usually occur in the extremities. A paratesticular localization is rare; the tumor develops from mesenchymal tissues of the spermatic cord, and epididymis.
There are two frequency peaks found for the development of rhabdomyosarcoma, the first at the age of 4 years and the second at the age of 18 years, as in our case. There is no predilection for race
The consensus is that this tumor derives from mesenchymal elements of the testis envelope, epididymis and spermatic cord. The tumor manifests as a hard painless inguinoscrotal swelling, the size and duration of development are varied and it rarely invades the scrotal skin. The mass might evolve within the external inguinal ring away from the scrotal contents
[2, 3]. A clinical examination should be complemented by an examination of the lymph nodes and a general examination to investigate metastases. Differential diagnoses include testicular torsion, orchiepididymitis, scrotal abscess and, rarely, testicular tuberculosis.
A testicular ultrasound is routinely performed for a scrotal mass. This imaging modality shows a mass with heterogeneous echogenicity and inguinoscrotal extension in 80% of cases
. This allows the nature of the intrascrotal tissue mass to be determined and specifies the exact topography. Ultrasound is used to establish the differential diagnosis and eliminate diagnoses of simple cyst and varicocele.
A thoraco-abdomino-pelvic CT scan allows for any deep invasion of the lymph nodes to be investigated, especially lombo-aortic and pelvic metastases as well as possible metastases to the liver or lung. Most authors prefer the use of thoraco-abdomino-pelvic CT compared to ultrasound for lymphomas.
Magnetic resonance imaging is an efficient imaging modality when using surface coils. The tumor appears homogeneous in T1-weighted images and heterogeneous in T2-weighted images with signal intensity similar to that in a normal testis. The low signal intensity of the tunica albuginea in T2-wieghted images allows the visualization of a clear separation of the mass from the testis
[1, 5, 6].
In rhabdomyosarcoma, tumoral markers including alpha-fetoprotein, beta-human chorionic gonadotropin and carcinoembryonic antigen are usually normal. This was the case with our patient.
A malignant tumor might be suspected in masses sitting in the distal cord with a hard and irregular form adhering to surrounding structures; a rapid increase in tumor volume might be noted. But the diagnosis is mainly made using histology. The macroscopic features include a lobed tumor surrounded by whitish pseudocapsules, hemorrhagic array are sometimes revealed
There are four histological types of rhabdomyosarcoma: pleomorphic, alveolar, botryoidal, and embryonal, such as found in our patient. The characteristic cell is rhabdomyoblast, which is not necessary for the diagnosis. Whenever rhabdomyoblasts are not present, immunohistochemical investigations are conducted using a panel of antibodies including myosin and desmin
[6, 8, 9].
Rhabdomyosarcoma may be included in the differential diagnosis for other paratesticular sarcomas such leiomyosarcoma, liposarcoma and fibrosarcoma. However, these pathologies occur more often in adults. Imaging cannot discriminate between these tumors. The final diagnosis can be established by histological study after surgical excision of the tumoral mass
Radical orchidectomy by the inguinal route with first cord ligation remains the essential act for histological diagnosis and constitutes the first step of treatment regardless of the stage of the disease. Hemiscrotectomy associating inguinal treatment is indicated first in scrotal cases whenever local invasion or presence of lymph are clinically evidenced
[6, 7]. An inguinal lymphadenectomy should not be performed without first obtaining imaging, including a CT scan or lymphography.
Chemotherapy should be routinely administered since rhabdomyosarcoma is chemosensitive. This therapeutic approach consists of administrating actinomycin D, vincristine and cyclophosphamide
[5–7, 10]. Radiotherapy is a complementary treatment of chemotherapy and surgery to eliminate residual foci and retroperitoneal lymph nodes.
Our patient benefited from an inguinal orchiectomy. Three sessions of chemotherapy were performed, resulting in no signs of metastasis or residual foci.