Clear cell renal cell carcinoma with intratumoral and nodal extramedullary megakaryopoiesis: a potential diagnostic pitfall

• Published in: Human pathology Vol. 45; no. 6; pp. 1306 - 1309
• Main Authors: Williamson, Sean R., MD, Mast, Kelley J., MD, Cheng, Liang, MD, Idrees, Muhammad T., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-06-2014; Elsevier Limited
• Subjects: Aged, 80 and over; Bone marrow; Breast cancer; Carcinoma, Renal Cell - complications; Carcinoma, Renal Cell - pathology; Clear cell renal cell carcinoma; Extramedullary hematopoiesis; Hematopoiesis, Extramedullary; Humans; Kidney; Kidney Neoplasms - complications; Kidney Neoplasms - pathology; Lymph Nodes - pathology; Lymphatic system; Male; Megakaryocytes; Megakaryocytes - pathology; Myelofibrosis; Pathology; Polycythemia - complications; Polycythemia - pathology; Tumors; Clear cell renal cell carcinoma; Megakaryocytes; Myelofibrosis; Extramedullary hematopoiesis; Kidney
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2014.01.011

Summary Clear cell renal cell carcinoma is occasionally associated with erythrocytosis, hypothesized to result from tumoral production of erythropoietin. Rarely, intratumoral erythropoiesis has been identified, although intratumoral megakaryopoiesis has not, to our knowledge, been previously described. We report the case of an 81-year-old man with myelofibrosis who underwent resection of a 9.8-cm clear cell renal cell carcinoma. Numerous megakaryocytes were present within the renal cell carcinoma; regional lymph nodes; and, to a lesser extent, the nonneoplastic kidney, glomeruli, and renal hilar soft tissue, in some areas associated with trilineage hematopoiesis. Immunohistochemistry verified the megakaryocytic lineage of the atypical cells (CD61, CD42b, and von Willebrand factor +; cytokeratin −). Intratumoral extramedullary megakaryopoiesis is a novel finding in clear cell renal cell carcinoma with potential to mimic high-grade carcinoma and involvement of lymph nodes. Careful attention to morphology, presence of other hematopoietic elements, and immunoprofile can facilitate recognition of this rare phenomenon.