Metastatic Tonsillar Malignant Melanoma Presenting as an Ovarian Mass

Background Metastasis of malignant melanoma to the ovary is exceedingly rare, poses significant diagnostic challenges, and carries an unfavorable prognosis. It most commonly presents in women of reproductive age as a unilateral or bilateral adnexal mass and who have a history of cutaneous melanoma. For most patients, widespread metastases tend to occur, making it a poor prognosis. The cornerstone of therapy for these patients involves surgical intervention, mainly salpingo‐oophorectomy, with chemotherapy and immunotherapy for disseminated disease. Case Presentation This case report highlights a 38‐year‐old female who was diagnosed with malignant melanoma revealed during a tonsillectomy, which later spread to the brain. She then presented with left flank pain, which on imaging showed a 3.5 cm cystic left adnexal mass, which eventually resolved, and an incidentally found hypermetabolic 6.7 cm pelvic mass in the right adnexa. Despite normal initial CA‐125 levels, her persistent right pelvic mass was confirmed to be metastatic melanoma in the right ovary and fallopian tube during a laparoscopic right salpingo‐oophorectomy. The patient is now postoperative and undergoing immunotherapy. Conclusion While metastatic melanoma to the ovary is rare, it is important to include it as a differential diagnosis in women of reproductive age who have a history of melanoma. Diagnosing it accurately requires a balance of clinical history, appropriate imaging, and also immunohistochemical analysis such as S‐100, HMB‐45, and MART‐1 to help distinguish it from other primary ovarian cancers. Accurate and early recognition is essential to guide management while optimizing systemic therapy and strategies for surveillance.