Malignant neoplasm of undescended testis

This code signifies a cancerous growth originating in a testis that has not descended into the scrotum. This condition is a serious complication of cryptorchidism, where the undescended gonad undergoes malignant transformation. The neoplasm is typically a germ cell tumor.

Apply this code when documentation confirms a primary malignant tumor located within an undescended testis. This diagnosis is often made following orchiectomy or biopsy of an intra-abdominal or inguinal testis mass. Supporting documentation should clearly specify both the malignancy and the cryptorchid (undescended) nature of the affected testis.

• Ensure the documentation explicitly states "undescended testis" in conjunction with the malignancy; simply "testicular cancer" is insufficient.
• Do not confuse with malignant neoplasms of a normally descended testis; a different code would apply in that scenario.
• Code any associated cryptorchidism (e.g., congenital absence or undescended testis) as a secondary diagnosis if still present and relevant.