Observer variability in the histopathological reporting of core biopsies of papillary breast lesions is reduced by the use of immunohistochemistry for CK5/6, calponin and p63.
OBJECTIVE
To investigate agreement on core biopsy diagnosis of papillary breast lesions, which is acknowledged as a difficult area, and to determine the effect of the use of immunohistochemistry (IHC) to assist diagnosis.


METHODS
Haematoxylin and eosin (H&E) sections of 129 core biopsies of papillary breast lesions were circulated to four observers who categorized each case as: B2 (benign), B3a (epithelial proliferation, probably benign but requiring biopsy), B3b (epithelial proliferation with cytological or architectural atypia), B4 (probably malignant but insufficient material or artefact to allow diagnosis), B5 (malignant papillary lesion). In all cases (n = 127) IHC was performed for cytokeratin (CK) 5/6, calponin, p63 (myoepithelial markers), and slides recirculated.


RESULTS
There was unanimous agreement in 44% of cases on H&E only which rose to 91% after the use of IHC. Overall, unweighted kappa (Ku; five categories) rose from 0.54 to 0.91. The main effect of IHC was to reduce the use of intermediate categories (B3a, B3b and B4) and allow definitive diagnosis (B2 or B5).


CONCLUSIONS
Agreement on H&E sections alone in papillary core biopsies of breast is only 44% (Ku = 0.54) but is significantly increased to 91% (Ku = 0.91) by the use of IHC for CK5/6, calponin and p63.
Douglas-Jones
A
A
School of Medicine, Cardiff University and Department of Pathology, University Hospital of Wales, Cardiff, UK. douglas-jones@cf.ac.uk
Shah
V
V
Morgan
J
J
Dallimore
N
N
Rashid
M
M
D014408:Biomarkers, Tumor / Q000032:analysis*; D001707:Biopsy, Needle; D001940:Breast / Q000737:chemistry / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002135:Calcium-Binding Proteins / Q000032:analysis; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology*; D004268:DNA-Binding Proteins; D003937:Diagnosis, Differential; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D053555:Keratin-5; D007633:Keratins / Q000032:analysis; D008840:Microfilament Proteins; D015588:Observer Variation; D010750:Phosphoproteins / Q000032:analysis; D015534:Trans-Activators / Q000032:analysis; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000096985:Calponins
D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D053555:Keratin-5; D007633:Keratins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000096985:Calponins; C503940:KRT5 protein, human; C115051:TP63 protein, human