MIB-1 immunohistometry of follicular adenoma and follicular carcinoma of the thyroid gland.
OBJECTIVE
To analyze cellular proliferative activity, MIB-1 immunopositivity of normal tissue (n = 20), follicular adenoma (n = 30) and follicular carcinoma (n = 32) of the thyroid gland was analyzed by means of immunohistometry.


METHODS
Immunohistochemical reactions were performed on 3-micron sections from routinely formalin fixed and paraffin embedded surgical specimens using an indirect peroxidase method. The rate of immunostained cells was determined using the CM-2 TV image analysis system (Hund, Wetzlar, Federal Republic of Germany). Forty viewing fields (1.94 mm2) were measured with 20:1 objective magnification. An average of 5,965 cells were assessed in each case.


RESULTS
Mean MIB-1 immunopositivity was higher in follicular carcinoma (average, 2.30%) and follicular adenoma (0.58%) than in normal thyroid tissue (0.14%). The distribution of single values differed significantly between groups (P < .001). To test the suitability of MIB-1 immunohistometry for the differential diagnosis of follicular adenoma and follicular carcinoma, different four-field tables with varying thresholds were calculated. Using a threshold of 0.9%, follicular carcinoma could be detected with a sensitivity of 75% (24/32) and a specificity of 83% (25/30). If a specificity of 90% is required (27/30), the sensitivity of the test decreases to 69% (22/32), based on a threshold of 1.1%.


CONCLUSIONS
As some overlap of single values has to be considered, MIB-1 immunohistometry, although presenting new insights into the proliferative potential of thyroid lesions, is of only limited value for the differential diagnosis of follicular lesions in routine surgical pathology.
Rickert
D
D
Department of Otorhinolaryngology, Technical University of Aachen, Federal Republic of Germany.
Mittermayer
C
C
Lindenfelser
R
R
Biesterfeld
S
S
D018263:Adenocarcinoma, Follicular / Q000737:chemistry / Q000175:diagnosis*; D000236:Adenoma / Q000737:chemistry / Q000175:diagnosis*; D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D019394:Ki-67 Antigen; D009687:Nuclear Proteins / Q000032:analysis*; D011230:Precancerous Conditions / Q000737:chemistry / Q000175:diagnosis*; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000175:diagnosis*
D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D009687:Nuclear Proteins