Primary malignant amelanotic melanoma in the female genital tract: A report of six cases and a review of the literature

Objective To analyze the clinical characteristics, pathologic diagnosis, treatment and prognosis of amelanotic melanoma in the female genital tract (AMFGT). Methods The medical records of 6 patients with AMFGT between 1991 and 2006 in our hospital were reviewed. Results Of these cases, 4 were preliminarily misdiagnosed as chorioepithelioma, sarcoma, adenocarcinoma or lymphoma. Two patients were determined to have AMFGT preoperatively after positive immunohistochemical staining for both S-100 protein and HMB-45. Specimens removed from all 6 cases were tested for immunohistochemical staining, as well as H&E histochemical stains. S-100 and vimentin were both positive in all patients, and HMB-45 was positive in 3 out of 5 patients. Four patients recurred (at 6, 6, 12 and 19 months) after primary treatments. Three patients died (at 13, 18 and 19 months) after the initial diagnosis. Conclusion Because of an absence of pigmentation AMFGT is extremely difficult to diagnose. Combined immunohistochemical staining, such as the S-100 protein, HMB-45 and vimentin etc, is important in the evaluation of AMFGT. Correct diagnosis plays a crucial role in the treatment of this disease.