Bone Marrow Metastasis of Solid Tumors: A Study of 174 Cases Over 2 Decades from a Single Institution in India.

To analyze the pathological findings in patients with marrow metastasis from solid tumors and to compare the accuracy of the bone marrow aspirate, trephine imprint and trephine biopsy in detecting metastasis. A total number of 174 cases diagnosed on bone marrow aspiration and/or bone marrow biopsy from January 2000 to December 2018 were included in the study. In addition to clinical and demographic data, we evaluated peripheral blood findings, and pattern as well as morphology of the tumor cells in bone marrow aspirate, imprint cytology and biopsy. The changes in the bony trabeculae were classified according to the classification of carcinomatous osteodysplasia. The most common laboratory findings included cytopenias and leucoerythroblastic blood picture. Trephine biopsy was found to be the most sensitive technique for detection of marrow metastases with a sensitivity of 99.4%. Trephine imprint cytology (89.9%) showed a significantly better detection rate than bone marrow aspiration (58.5%). Metastatic adenocarcinomas and undifferentiated carcinomas were more common than non-epithelial tumors. Metastatic carcinomas with known primary were mostly from breast, prostate and lung. Ewings/PNET and neuroblastoma were the commonest among metastatic non-epithelial tumors. Fibrosis (53.4%) was the most frequent stromal change and abnormalities in bony trabeculae were noted in 61.2% cases. Trephine biopsy has the highest sensitivity in detection of marrow metastasis followed by trephine imprint cytology. Immunohistochemistry on trephine section will help in confirming and or suggesting the primary tumor in unknown cases.