Primary bone metastasis as initial presentation of endometrial cancer (stage IVb)

Abstract

Endometrial cancer is the most common malignancy among females in developed countries. Abnormal uterine bleeding is the leading symptom in approximately 90% of cases. The incidence of stage IV disease is approximately 5-10% with a 5-year overall survival of less than 10%. A rare case presented with femoral pathological fracture and underlying endometrial cancer. We discuss the diagnosis, management and literature review for this extremely rare entity which can be present even in the absence of vaginal bleeding. Literature search revealed 28 cases with primary bone metastasis and all were symptomatic at the time of diagnosis. Eighty percent of them had tumour on the lower limb and the majority did not have vaginal bleeding. The predominant histopathological type was endometrioid (72.4%) and grade 1-2 (59%). Treatment had been individualised and 57% of the cases underwent surgery with removal of uterus and adnexa and only three patients (10.7%) received pelvic radiotherapy. Bone tumour was treated with radiotherapy in 80% of the cases, alone (28%), or combined with primary surgery (12%) or chemotherapy (40%). Overall, 54% of patients received chemotherapy and 46% received hormone therapy. The mean survival of patients who presented with single-bone metastasis was significantly better than those with multiple extrauterine metastatic sites: mean 85.7months (SE: 9.2) versus 22.9months (SE: 5.2), p<0.003, CI 95%. These two different survival patterns are more likely to reflect two different biological disease behaviours. Those with advanced local and widespread disease progress quicker, in contrast to those with a single-bone extrauterine metastatic site and local disease limited to the uterus, which continues to behave as early stage endometrial cancer. Although extremely rare, endometrial cancer can present as initial bone pathology. Endometrial biopsy should be included in the patient's workup when investigating for metastatic bone adenocarcinoma of unknown origin, even when gynaecological symptoms are lacking, as this rare presentation of stage IVb endometrial cancer appears to have good survival outcomes.