A rare case of inguinal metastatic malignant melanoma with unknown primary

Background: Metastatic melanoma with unknown primary (MUP) accounts for approximately 2-9% of cases of metastatic melanoma [1]. This case report highlights the importance of detailed history taking and physical examination to look for a primary lesion. Case presentation: This is a case report of a 55 years old female with right inguinal region mass. Histopathologically proven to be metastatic malignant melanoma, primary lesion is unknown. Positron Emitted Tomography/Computed Tomography revealed involvement of right external iliac lymph nodes. The patient underwent Right Ilio-inguinal Block Dissection. Post-operatively, she was started on Adjuvant Immunotherapy. Conclusion: ■ This clinical scenario signifies that occult metastatic melanoma should be considered in the differential diagnosis for any patient presenting with a malignancy of unknown origin. ■ Patient education regarding self examination to look out for new symptoms and signs and regular follow-up is of utmost importance. ■ Regional lymph node dissection followed by adjuvant immunotherapy approach is found to improve recurrence-free survival.