Synovial Sarcoma of Testis: a Rare Tumour at an Uncommon Site—A Case Report

Abstract

Neoplasms of testis are relatively rare with an incidence of approximately 1% of cancers in men diagnosed worldwide. Germ cell tumours form around more than 95% of testicular neoplasm. Primary synovial sarcoma of testis is exceedingly rare and soft tissue sarcoma forms around 1% of all adult malignancies. Among sarcomas, synovial sarcoma is about 5 to 10%. It is a mesenchymal tumour which affects children and young adults and mostly involves extremities. This is the second case being reported in the literature. We report the case of a 35-year-old man who presented with a left testicular mass and underwent radical high inguinal orchiectomy. Lost to follow-up, he returned with a recurrent mass in the left inguinoscrotal region. He underwent wide local excision with systemic chemotherapy (a combination of ifosfamide and doxorubicin)and radiotherapy postoperatively. He succumbed to the disease in a year. The prognosis is guarded as the optimal therapy is unknown.

Introduction

Neoplasms of testis are relatively rare with an incidence of approximately 1% of cancers in men diagnosed worldwide [1]. Germ cell tumours form around more than 95% of testicular neoplasm [2]. Primary synovial sarcoma (SS) of testis is exceedingly rare and soft tissue sarcoma forms around 1% of all adult malignancies [3]. Among sarcomas, synovial sarcoma is about 5 to 10% [1]. It is a mesenchymal tumour which affects children and young adults and mostly involves extremities [3]. Surgical extirpation with adjuvant chemotherapy (combination of ifosfamide and doxorubicin) and radiotherapy looks to be the way forward. The prognosis is guarded as the optimal therapy has yet not been found.

Case Presentation

A 35-year-old man presented with painless left testicular swelling for 6 months. He did not give any previous history of trauma or surgery and was married with one male child. He was a farmer by occupation. On examination, the swelling was around 8* 5 cm and the other testis was normal on examination with ECOG Grade 0. There was no palpable inguinal or abdominal lymphadenopathy. Ultrasonography of the scrotal and inguinal region revealed a large left testicular mass around 82* 42 mm. MRI scrotum showed a well-defined heterogeneously enhancing testicular mass lesion involving the left testis with areas of necrosis, and haemorrhage which shows diffusion restriction suggestive of malignant aetiology (Fig. 1). Beta human chorionic gonadotropin and alpha-fetoprotein were normal with serum lactate dehydrogenase being marginally raised. He underwent high inguinal radical orchidectomy and histopathology examination reported poorly differentiated malignant spindle cells suggestive of synovial sarcoma and immunohistochemistry came positive for CD-99. SMA, MYO D-1, DESMIN and INHIBIN were negative.

Fig. 1.

MRI of left testis on first visit

He was advised chemotherapy but was lost to follow-up and returned with recurrent swelling at the left inguinoscrotal region around 12*10 cm (Fig. 2) after 4 months. Contrast-enhanced CT scan of the abdomen with the pelvis (Fig. 3) showed a well-defined heterogeneously enhancing lobulated lesion involving the left scrotal sac with abutments with few prominent lymph nodes in the left inguinal region, no nodes in retroperitoneum. CT thorax was normal. He underwent wide local excision of recurrent mass (Figs. 4 and 5). Histopathology examination reaffirmed it as a poorly differentiated synovial sarcoma (Figs. 6 and 7) Immunohistochemistry showed positivity for CD 99 (Fig. 8), SS18 (Fig. 9) TLE-1, CK and EMA, and it was negative for SMA, Desmin and Myogenin [4–8].

Fig. 2.

Recurrent left inguinoscrotal mass

Fig. 3.

CECT (A + P) of left inguino scrotal mass

Fig. 4.

Resected recurrent mass

Fig. 5.

Immediate postoperative period

Fig. 6.

Few areas show tumour necrosis

Fig. 7.

Sections show cellular neoplastic spindle cells in interlacing fascicles

Fig. 8.

Immunohistochemistry (CD 99) with histopathology of tumour

Fig. 9.

Neoplastic cells show diffuse and strong nuclear SS18 immunoexpression

According to the National Federation of Centre Agency Cancer, it was classified as grade III and molecular analysis showed t(X;18). He underwent Chemotherapy with Radiation at the local site (Fig. 10).

Fig. 10.

Post-chemotherapy and radiotherapy status

After 6 months of follow-up which included three monthly physical examinations, basic blood investigations (complete blood count, liver function test, renal function test, tumour markers like serum lactate dehydrogenase) with contrast-enhanced computerised tomography of the abdomen with the pelvis (CECT (A + P)) with the thorax, he was lost to follow-up. He returned with local site recurrence and metastasis to the lungs and deteriorated and he eventually succumbed to the aggressive nature of synovial sarcoma.

Discussion

Synovial sarcoma is a slow-growing neoplasm which affects age groups between 15 and 40 years and involves extremities. Synovial sarcoma involving the penis, prostate, etc. has been reported and this is the second case to be reported in the literature [5–7, 9]. With over 100 identified histological types of soft tissue sarcomas (STS), accurate diagnosis can be challenging for pathologists without extensive sarcoma experience [10, 11].

The SS18::SSX fusion oncogene is likely to be the driving oncogenic event in SS [12].

Typically, SS metastasises to the lungs, lymph nodes and bone (in ∼ 80%, 7–20% and 2–5% of patients, respectively) [13, 14].

For soft tissue sarcomas, 5-year and 10-year overall survival rates have been between 24–68% and 11–56%, respectively [5].

Treatment guidelines recommend surgical resection with wide excision and negative margins when possible in cases of localised STS. This should be combined with radiotherapy (neoadjuvant or adjuvant) for intermediate to high-grade (grades 2–3), deep lesions larger than 5 cm [15]. Radiotherapy reduced local recurrence reduction. It is also recommended when the margins are positive [14, 16]. ESMO guidelines recommend three cycles of neoadjuvant full-dose anthracycline plus ifosfamide chemotherapy, with non-inferior overall survival (OS) compared to five cycles, treatment recommendations for patients with rarer STS histological types should be made on an individual basis [15, 17].

Chemotherapy is administered in metastatic cases, or if surgery is incomplete, it can be given in recurrent cases. A combination of ifosfamide and doxorubicin is being used in the first-line therapy. A combination of gemcitabine and docetaxel is another therapeutic option [7]. Prognosis used to be poor with a survival period of only two months, but with aggressive chemotherapy, a survival rate of 14 years has been reported [5]. Recent clinical trials which used genetically modified T-cells expressing a T-cell receptor targeting NY-ESO-1 showed the success of immunotherapy in synovial sarcoma with a response of 45 to 67% and low toxicity as no normal tissue expresses this antigen [7].

Many clinical trials are going on in the treatment of metastatic soft tissue tumours (including synovial sarcoma) which include drugs like Anlotilib, Tazemetostat, etc [7, 8].

Declarations

Conflict of Interest

The authors declare no competing interests.