Synovial Sarcoma of the Vulva and Vagina: A Clinicopathologic and Molecular Genetic Study of 4 Cases

Poorly differentiated biphasic synovial sarcoma of the vulva, displaying SS18::SSX1 fusion and weak to absent (mosaic) INI1/SMARCB1 immunostaining: A rare case with literature review

ABSTRACT

Synovial sarcoma (SS) is rarely documented in the female genital tract, especially confirmed by molecular testing for SYT::SSX translocation and TLE1 immunostaining. A 62-year-old lady presented with a progressively increasing lump and pain over her right groin, for 6-month duration. Radiologically, a well-defined, solid-cystic mass was seen involving the right labia with necrotic areas, sparing the underlying muscles and the overlying skin. She underwent a biopsy followed by a surgical excision. Histopathologic examination revealed a spindle cell sarcoma, including tumor cells exhibiting a prominent hemangiopericytomatous pattern. There were focal areas of epithelial differentiation (pseudoglandular) along with areas of round cell morphology and increased mitoses (poor differentiation) in the resected specimen. Immunohistochemically, the tumor cells were diffusely positive for TLE1, patchily positive for pan keratin (AE1/AE3) and EMA, the latter more in the areas of epithelial differentiation, while negative for CD34, SMA, desmin, S100P, and SOX10. INI1/SMARCB1 showed a characteristic weak to absent (mosaic) staining pattern. Furthermore, the tumor displayed SS18::SSX 1 fusion by RT-PCR. This constitutes one of the few reported cases of vulvar SS, confirmed by molecular testing and the first documented vulvar SS showing a mosaic pattern of INI1/SMARCB1 immunostaining. A review of the literature and diagnostic implications are presented herewith.

Synovial sarcoma of female urethra: a case report and review of the literature

Synovial sarcoma (SS) is a rare malignant soft tissue sarcoma that originates from primitive mesenchymal cells with epithelial differentiation potential. It is most commonly found in the limbs and trunk. In the urinary system, it is mostly found in the kidneys. However, synovial sarcomas originating from the external urethra are extremely rare. Only one case of synovial sarcoma arising from the vulvar urethral orifice has been reported previously, and we report a second case of synovial sarcoma of the urethral orifice. In addition, a total of 16 vulvar synovial sarcomas were identified and the literature are analyzed in this report reviews from 1966 to the present.

Synovial sarcoma of the vulva: A case report and literature review with discussion on fertility sparing approaches

•Vulvar synovial sarcoma is a rare malignancy with unclear treatment guidelines but usually includes surgical resection.•Our literature review demonstrates additional survival benefit from addition of radiotherapy to surgical resection.•There is no specific guidance in the literature for the addition of systemic agents to treat vulvovaginal disease.•Our patient received wide surgical excision and IMRT radiotherapy with no signs of recurrence 2 years from treatment.•She conceived after treatment. This has only been documented once before with different, less accessible treatments.

Synovial Sarcoma of the Female Genital Tract: A Protean Mimic of Müllerian Neoplasia

Synovial sarcoma most commonly occurs in the extremities but has rarely been described in the female genital tract. In this series, we describe the clinical, morphologic, immunohistochemical, and molecular features of 7 cases of vulvovaginal synovial sarcoma (vulva, n=6; vagina, n=1). We emphasize their wide morphologic spectrum, which can overlap significantly with other more common tumors at these sites, as highlighted by 2 cases initially diagnosed as other entities (endometrioid carcinoma and malignant peripheral nerve sheath tumor). The average patient age was 41 (range: 23 to 62) years and tumor size ranged from 0.8 to 7 cm. Histologically, the tumors were biphasic (n=6) and monophasic (n=1). All cases were confirmed with fluorescence in situ hybridization or sequencing, and 5/5 cases were positive for the novel immunohistochemical markers SSX and SS18-SSX. In 3 cases with follow-up, 2 patients died of disease and 1 was alive with no evidence of disease. Previously described cases arising in the female genital tract are also reviewed. Vulvovaginal monophasic synovial sarcoma raises a broad differential diagnosis, including smooth muscle tumors, spindled carcinomas, and melanoma. Biphasic synovial sarcoma may mimic Müllerian carcinosarcoma, endometrioid carcinoma with spindled, corded, and hyalinized elements, and mesonephric-like adenocarcinoma. Awareness that synovial sarcoma can occur in the female genital tract with a wide variety of histologic appearances is critical for correctly diagnosing this rare entity. In particular, synovial sarcoma should be considered for any deeply situated "adenocarcinoma" in the vulva, with attention to subtle spindle cell differentiation.

Mesenchymal lesions of the vulva

Mesenchymal lesions of the vulva include site-specific entities limited to the lower genital tract, as well as a range of non-site-specific tumors that are more common at extragenital sites. Site-specific lesions include fibroepithelial stromal polyp, cellular angiofibroma, angiomyofibroblastoma, and aggressive angiomyxoma. Non-site-specific tumors that may occur in the vulva include those of smooth muscle, skeletal muscle, vascular, neural, adipocytic, and uncertain differentiation. This review discusses both site-specific and non-site-specific vulvar mesenchymal lesions including non-neoplastic proliferations, benign neoplasms, locally aggressive neoplasms with a predilection for local recurrence, neoplasms of indeterminate biologic potential, and frankly malignant neoplasms with a high risk of distant metastasis and death. Accurate diagnosis is essential for proper management, and is facilitated by correlation with clinical findings and targeted application of immunohistochemical and molecular studies.

Vulvar sarcoma outcomes by histologic subtype: a Surveillance, Epidemiology, and End Results (SEER) database review

OBJECTIVE

Vulvar cancers account for 5% of all gynecologic malignancies; only 1%-3% of those vulvar cancers are primary vulvar sarcomas. Given the rarity of vulvar sarcomas, outcome data specific to histopathologic subtypes are sparse. The aim of this study was to identify clinical and pathologic factors of primary vulvar sarcomas that are associated with survival and may inform treatment decisions.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was searched for women diagnosed with vulvar sarcoma between 1973 and 2018. We identified 315 patients and reviewed their demographic, clinicopathologic, surgical, and survival information. Statistical analyses included χ2 and t-tests, Kaplan-Meier survival, and Cox regression analyses.

RESULTS

The most common histopathologies of vulvar sarcomas were dermatofibrosarcomas (85/315, 27%) and leiomyosarcomas (72/315, 22.9%). Rhabdomyosarcomas (18/315, 5.7%), liposarcomas (16/315, 5.1%), and malignant fibrous histiocytomas (16/315, 5.1%) were less frequent. The majority of patients underwent surgery (292/315, 92.7%), which included lymph node dissections in 21.6% (63/292). Survival and lymph node involvement varied significantly with histologic subtype. The 5-year disease-specific survival for dermatofibrosarcomas, liposarcomas, and fibrosarcomas was 100% and only 60.3% and 62.5% for malignant fibrous histiocytomas and rhabdomyosarcomas, respectively. None of the patients with (dermato)fibrosarcomas, liposarcomas, or leiomyosarcomas had positive lymph nodes, in contrast to rhabdomyosarcomas and malignant fibrous histiocytomas with 77.8% and 40% positive lymph nodes, respectively. The 5-year disease-specific survival for women with positive lymph nodes was 0%.

CONCLUSIONS

Vulvar sarcomas are heterogeneous with survival highly dependent on the histopathologic subtype. While surgical excision is the mainstay of treatment for all vulvar sarcomas, staging lymphadenectomy should be deferred for (dermato)fibrosarcomas, liposarcomas, and leiomyosarcomas as there were no cases of lymph nodes metastases.

Vulvar sarcomas: Short guideline for histopathological recognition and clinical management. Part 2

Malignant tumors of the female reproductive system are a serious health and social problem, as they are the second most common cause of death among women, after breast cancer. Vulvar tumors represent only 4% of all gynecological neoplasms, and they are fourth in frequency after tumors of the cervix, uterus, and ovary. Ninety-eight percent of all vulvar tumors are benign and only 2% are malignant. Sarcomas of the vulva comprise approximately 1–3% of all vulvar cancers. They are characterized by rapid growth, high metastatic potential, frequent recurrences, aggressive behavior, and high mortality rate. In Part 1 of this paper, we presented the most common forms of sarcoma of the vulva: leiomyosarcoma, epithelioid sarcoma, malignant rhabdoid tumor, and rhabdomyosarcoma. The second part of this review will focus mainly on the rarest variants of vulvar sarcoma: low-grade fibromyxoid sarcoma, synovial sarcoma, monophasic synovial sarcoma, carcinosarcoma, Ewing sarcoma, myeloid sarcoma, dermatofibrosarcoma protuberans, malignant fibrous histiocytoma, angiomatoid fibrous histiocytoma, liposarcoma, malignant peripheral nerve sheath tumor, and malignant mesothelioma.

Synovial sarcoma: defining features and diagnostic evolution

Synovial sarcoma (SS) is a malignant mesenchymal neoplasm with variable epithelial differentiation, with a propensity to occur in young adults and which can arise at almost any site. It is generally viewed and treated as a high-grade sarcoma. As one of the first sarcomas to be defined by the presence of a specific chromosomal translocation leading to the production of the SS18-SSX fusion oncogene, it is perhaps the archetypal "translocation-associated sarcoma," and its translocation remains unique to this tumor type. Synovial sarcoma has a variety of morphologic patterns, but its chief forms are the classic biphasic pattern, of glandular or solid epithelial structures with monomorphic spindle cells and the monophasic pattern, of fascicles of spindle cells with only immunohistochemical or ultrastructural evidence of epithelial differentiation. However, there is significant morphologic heterogeneity and overlap with a variety of other neoplasms, which can cause diagnostic challenge, particularly as the immunoprofile is varied, SS18-SSX is not detected in 100% of SSs, and they may occur at unusual sites. Correct diagnosis is clinically important, due to the relative chemosensitivity of SS in relation to other sarcomas, for prognostication and because of the potential for treatment with specific targeted therapies in the near future. We review SS, with emphasis on the diagnostic spectrum, recent immunohistochemical and genetic findings, and the differential diagnosis.

Synovial sarcoma arising in the vulva cytogenetically confirmed by SYT break-apart rearrangement fluorescence in situ hybridization: A case report and discussion of diagnostic methods

Synovial sarcoma (SS) is a soft tissue sarcoma of unknown histogenesis that rarely occurs in the female genital tract. We report a case of SS occurring in the right vulva of a young Japanese female. The tumor was composed of poorly differentiated rounded cell areas, surrounded by fibroblastic spindle-shaped cell areas. Immunohistochemically, the tumor cells were focally positive for cytokeratin, vimentin, CD99, Bcl-2 and neuron-specific enolase. The tumor was suspected, but was difficult to confirm as it was an SS based solely on light-microscopic and immunohistochemical findings. Although reverse transcription polymerase chain reaction (RT-PCR) failed to detect SS-specific SYT-SSX fusion gene transcripts using an RNA sample extracted from the formalin-fixed paraffin-embedded tumor tissue, SYT break-apart rearrangement fluorescence in situ hybridization (SYT bar-FISH) successfully confirmed our diagnosis of SS for the tumor. Thus, SYT bar-FISH may be more suitable for the purpose of the molecular diagnosis of SS than conventional RT-PCR when using archival formalin-fixed paraffin-embedded tissue specimens.