Unraveling the Complexities of Proximal-Type Epithelioid Sarcoma of the Vulva

Purpose: To present a rare case of proximal-type epithelioid sarcoma (PES) of the vulva and highlight the importance of a multidisciplinary approach in its diagnosis and treatment, especially in the context of SMARCB1 loss. Methods: A 41-year-old woman presented with a painless mass in the right labia majora. An MRI, PET/CT, histopathology, and immunohistochemistry confirmed the diagnosis of PES with loss of SMARCB1 expression. The patient underwent wide local excision followed by re-excision and inguinal lymphadenectomy. Adjuvant radiotherapy was initiated but discontinued at 46 Gy due to grade 2 skin reactions and wound dehiscence. Results: Posttreatment PET/CT imaging posed challenges in distinguishing between recurrence and radiation-induced changes. Despite these challenges, the patient remained disease free during the 2-year follow-up period. This case underscores the diagnostic and therapeutic complexities involved in treating PES, particularly in sensitive anatomical regions such as the vulva. The loss of SMARCB1 served as a key molecular marker guiding diagnosis and therapeutic decisions. Conclusion: The case underscores the importance of a comprehensive, individualized treatment approach, including surgery, radiotherapy, and advanced imaging, for managing rare malignancies such as vulvar PES.