Image of the Quarter (2015-1)
A good example of a tubulo-lobular carcinoma
50 year old woman - core biopsy-confirmed carcinoma - excision.
The tumour shows a low power pattern typical of lobular carcinoma however in some areas (a minority) there is evidence of tubular differentiation and the cytological detail of the tubular cells is also 'lobular'. 'Mouse-over' for closer view.
These further H&Es show areas of tubular differentiation. The 'Mouse-over' shows a focus of LCIS.
These views are of E cadherin immunostaining showing negative staining of the classical pattern lobular carcinoma and weak membrane staining of the tubular foci ('Mouse-over'). Contrast this with the strong crisp membrane staining of the cluster of ducts on the right of the image.
These final views are of beta catenin immunostaining of the two patterns of lobular carcinoma and the focus of LCIS ('Mouse-over'). The staining in the lobular areas is one of granular cytoplasmic staining. Again contrast this with the strong crisp membrane staining of the cluster of ducts top right and at the top of the mouse-over image.
The distinction between tubulo-lobular carcinoma and the mixed special type tubular and lobular causes difficulties for practitioners. In a truly mixed carcinoma the lobular & tubular elements will be true to their types morphologically and phenotypically i.e. the tubular element will be strongly membrane positive for e cadherin while the lobular element will be negative.
Tubulo-lobular carcinoma, in contrast will show a uniform (if aberrant sometimes) staining pattern with E cadherin (negative of only weakly positive)and also with beta catenin (cytoplasmic dot positivity). Tragically, there will always be imperfect examples!