Clear cell renal cell carcinoma with intratumoral and nodal extramedullary megakaryopoiesis: a potential diagnostic pitfall.
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.
Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI 48202. Electronic address: swilli25@hfhs.org.
Sean R
SR
Williamson
Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232.
Kelley J
KJ
Mast
Departments of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202; Department of Urology, Indiana University School of Medicine, Indianapolis, IN 46202.
Liang
L
Cheng
Departments of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202.
Muhammad T
MT
Idrees
D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000150:complications / Q000473:pathology*; D006411:Hematopoiesis, Extramedullary; D006801:Humans; D007680:Kidney Neoplasms / Q000150:complications / Q000473:pathology*; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008533:Megakaryocytes / Q000473:pathology*; D011086:Polycythemia / Q000150:complications / Q000473:pathology*
Clear cell renal cell carcinoma; Extramedullary hematopoiesis; Kidney; Megakaryocytes; Myelofibrosis