Vaginal Anaplastic Lymphoma Kinase (ALK)-Positive Mesenchymal Tumor in a Young Patient: Expanding the Spectrum of Rare Genitourinary Neoplasms.

Primary vaginal tumors are uncommon, and mesenchymal neoplasms in this location are even rarer, often resembling benign lesions such as fibroids or cysts. We present the case of a 20-year-old woman with a steadily enlarging anterior vaginal wall mass, initially suspected to be a fibroid based on clinical and radiological findings. Surgical excision revealed a spindle-cell proliferation with inflammatory infiltrates, and immunohistochemistry confirmed an anaplastic lymphoma kinase (ALK)-positive mesenchymal tumor. Postoperative imaging showed no residual disease, and a multidisciplinary team recommended surveillance given the complete excision and proximity of the lesion to the bladder trigone. This case emphasizes three clinical considerations: the importance of including rare mesenchymal tumors in the differential diagnosis of vaginal wall masses, the indispensable role of histopathology and immunohistochemistry in establishing a definitive diagnosis, and the need for tailored management strategies that balance oncologic control with preservation of function.