6-12,15) Our patient was diagnosed with concurrent mammary carcinoma and MALT lymphoma, presenting as
collision tumor, infiltrating each other and occupying a single tumor in the same breast.
31,32) Several reports have described GCTs in the breast to occur either in close proximity to an invasive adenocarcinoma (33,34) (within 2 cm) or as a component of a
collision tumor with adenocarcinoma invading into the GCT component.
Based on previous reports on the positive staining of the clear cell type of RCC for CA IX, (18) we performed immunostains for this carbonic anhydrase on our
collision tumor.
Subsequently, we used the staining properties of the urothelial and prostate carcinomas to verify a
collision tumor in the lymph node.
A Case Report of Unusual
Collision Tumors With Review of the Literature
The distribution of immunostaining correlated completely with the histologic distinction between the prostatic and mammary carcinoma components in the
collision tumor.
Gliosarcoma is a mixed tumor containing both malignant glial and mesenchymal tissues intermixed, unlike in the
collision tumor.
All of the theories seem to point to 2 basic mechanisms, which were initially proposed by Meyer in 1919:
collision tumor or combination tumor.
double dagger]) One case was a
collision tumor with malignant lymphoma.
The term basosquamous carcinoma has been used by some to describe BCC with squamous metaplasia as well as a prominent stromal proliferation, (17,18) although others apply the same name to
collision tumors in which a typical BCC is identified adjacent to SCC.
7), (8) Meyer (1920) classified carcinosarcomas into three histogenetic groups: 1)
collision tumors in which carcinoma and sarcoma arise simultaneously in proximity and subsequently invade each other, 2) combination tumors in which both tumors derive from pluripotent cells, and 3) composition tumors in which the components arise from the same tissue.
)