Collision tumor of the kidney composed of clear cell carcinoma and collecting duct carcinoma: report of a case with unusual morphology and clinical follow up

Abstract

We report the case of a 67-year-old female who presented with a large renal mass. Gross examination of the nephrectomy specimen demonstrated a 6-cm renal mass that invaded into the renal sinus and perinephric fat. Histologic examination revealed two distinct tumor types. The first type was a conventional (clear cell) renal cell carcinoma that was of low nuclear grade and comprised the minority of the overall tumor. The second type was a high-grade collecting duct carcinoma with glandular/tubular differentiation and composed the majority of the tumor. Immunohistochemical studies demonstrated distinctive patterns of the two tumor types, thus confirming two distinct lineages. Five months postoperatively, the patient developed metastasis to the lungs and right hilar lymph node region. A fine needle aspiration of a lung nodule demonstrated a metastatic, poorly differentiated carcinoma, similar to the collecting duct carcinoma component in the kidney. Collision tumors of the kidney are rare with fewer than 10 cases reported in the literature. Our report further expands the spectrum of this rare phenomenon.

Collision Carcinoma Involving Small Cell Neuroendocrine Carcinoma and Squamous Cell Carcinoma of the Ureter: A Case Report and Review of the Literature

“…Collision tumours are a rare tumour phenomenon in which two or more types of tumour occur simultaneously in the same organ, and there is no mixing between the different types of tumour components ( 17 ). The pathogenesis of ureteral collision carcinoma is unclear.…”

Intravascular Large B-Cell Lymphoma and Renal Clear Cell Carcinoma as Collision Tumor: A Case Report and Review of the Literature

“…There have been a few reports of collision tumors in the kidney, including RCC coexisting with collecting duct carcinoma, urothelial carcinoma and a Burkitt’s lymphoma. 24-26…”

Open partial nephrectomy for a collision renal cell carcinoma in a transplant kidney: A case report

“… 1 Collision tumours are very rare in the kidney, but have been reported to comprise of variants of primary RCC and metastases. 2 Renal cell carcinomas demonstrate histopathological differentiation according to the tumour epithelium of origin. Tumour variants display distinct immunohistochemical staining patterns.…”