Objective: Cancer of unknown primary in pregnancy is scarcely reported in literature. The mortality is very high and less than 25% survive beyond 1 year. The non-specific symptoms of pregnancy together with limited safe diagnostic modalities delays its early diagnosis hence resulting in the advanced stage of presentation with fatal outcome. Case report:We present a case of 30-year-old G3 A2 at 27 weeks amenorrhea with non-specific complaints of weakness of both lower limbs which on MRI revealed pathological fracture of T12 vertebra and a mass in the iliac region. Biopsy from the iliac mass revealed undifferentiated adenocarcinoma which suggested metastasis. Patient underwent LSCS at 30 weeks followed by spinal fixation for the pathological fracture on post-operative day 9. After two days of spinal fixation patient succumbed to cardiac arrest. Conclusion:Due to its rarity with acute deadly outcome, the previous literature related to the patients of cancer of unknown primary in pregnancy was reviewed and their final outcomes were studied.