Immunophenotypic characteristics of brain metastases

Abstract

Up to 15% of patients with secondary brain tumors of unknown primary are admitted to a neurosurgery department. Identification of a primary tumor site on the basis of surgical material immunophenotyping in routine clinical practice has a significant potential; however, this requires systematization.Objective: to detect the primary focus of brain carcinoma. Patients and methods.Surgical specimens from 7 patients with brain tumor of unknown primary were investigated using light optical microscopy and an immunohistochemical (IHC) panel including EMA, CK AE1/3, CK7, CK5/6, GFAP, S-100, Vimentin, p63, TTF-1, Uroplakin III (UPIII), CDX2, and Her2/neu.Results and discussion. A study using the IHC panel made it possible to obtain the following tumor phenotypes in the patients: CK5/6+, p63+, CK7+, UPIII+ (urothelial cancer) (n=3); CK5/6-, CK7+, TTF-1+, CDX2- (lung adenocarcinoma) (n=2); CK5/6+, p63+, CK7-, UPIII, TTF-1- (squamous cell carcinoma) (n=1), and CK5/6-, CK7+, TTF-1-, CDX2-, Her2/neu+ (breast cancer) (n=1). Evidence of the primary focus of the tumors was subsequently confirmed by instrumental techniques in all cases when cancer of the breast, lung and urinary system was directly sought. The findings were used to elaborate an algorithm for the differential diagnostic immunophenotyping of brain metastases.Conclusion. The primary focus of brain carcinoma was detected in all cases on the proposed IHC panel. The systematized algorithm for differential diagnostic immunophenotyping can be used in clinical practice.

Keywords

• metastases of unknown primary
• secondary tumor
• brain
• immunophenotyping