INTRODUCTION:Collision tumor is the meeting and eventual intermingling of two malignant neoplasms arising from independent topographical sites.
Collision metastases of carcinomas in lymph nodes are a rare event. A current literature search revealed three cases of such a collision metastasis of prostatic and urothelial carcinoma, and only one of those cases had used immunohistochemical stains to distinguish the two tumors.
CASE PRESENTATION: We encountered a case of this rare entity in an 83-year-old African-American man who presented with increasing pelvic pain after a transurethral resection [TUR] of a high-grade bladder tumor and a negative metastatic computed tomography [CT]-chest, abdomen and pelvic scan work-up. A radical cystoprostatectomy was subsequently performed revealing a multicentric, high-grade, ill-defined infiltrating urothelial carcinoma infiltrating the right pericystic soft tissue. Histopathological examination of the prostate revealed a multicentric adenocarcinoma [Gleason 4 + 4] involving two pelvic lymph nodes. Interestingly, while the right pelvic lymph node was positive for metastatic prostatic adenocarcinoma alone, immunohistochemical studies of the left pelvic lymph node revealed a dual metastatic urothelial [cytokeratin[CK]-7 and pan-CK positive, prostate specific antigen [PSA] and CK20 negative] and prostatic [PSA and pan-CK positive, CK7 and CK20 negative] carcinoma.
CONCLUSIONS: The collision of metastatic urothelial carcinoma and prostatic adenocarcinoma is unusual, and their biological behavior remains uncertain. A high index of suspicion along with thorough clinical examination, and immunohistochemical stains are an integral part of differentiating collision of urothelial carcinoma from prostate carcinoma, particularly when the two tumors are in close proximity with overlapping histological features.
Written by:
Bhavsar T, Liu J, Huang Y. Are you the author?
Reference: J Med Case Rep. 2012 May 14;6(1):124.
doi: 10.1186/1752-1947-6-124
PubMed Abstract
PMID: 22583918
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