Malignant melanoma metastatic to the endometrium. Cytologic findings in a direct endometrial sample.

A 38-year-old woman was hospitalized with uterine bleeding and a history of malignant melanoma. Endometrial biopsy had already documented the presence of rare uterine metastases from a cutaneous lesion surgically removed from the back 1.5 years previously. While a cervicovaginal smear was negative, smears of a sample obtained from the uterine cavity by the Mi-Mark endometrial helix showed the cytomorphologic features of melanoma, corresponding to those seen in the primary lesion. The finely granular cytoplasmic pigment seen in the smears was proven to be melanin by the use of potassium permanganate oxidation. The patient then underwent hysterectomy. This case demonstrates the potential utility of direct endometrial sampling in diagnosing difficult cases.