Increased serum levels of type IV collagen and laminin in a patient with a giant retroperitoneal schwannoma.

A 63 year old woman presented with a giant abdominal tumor. Ultrasonography, computerized tomography and drop-infused pyelography revealed a suspected retroperitoneal tumor. The tumor was removed surgically and weighted 2800 g. The pathological diagnosis of the tumor was schwannoma. Strong immunohistochemical staining specific for type IV collagen and laminin was observed in the tumor, and these components were localized in the pericellular region of Schwann cells. The serum levels of these antigens, as determined by radio-immunoassay, were very high before the operation but decreased rapidly thereafter.