Image of the Month (2011-2)
Metaplastic carcinoma with heterologous elements
Clinical cancer in a 45 year old female - macroscopically approx 25mm - low power view (x4) of core biopsy
Detail - from above. Extensive spindle cell differentiation with atypia. 'Mouse over' for further detail and note occasional mitoses.
Further view of widespread spindle cell pattern. Note focus osteoid in top left corner ('Mouse over')
Closer view of osteoid focus (heterologous element).('Mouse over') for a further view of more of the spindle cell area with another mitosis.
Detail showing focal epithelial differentiation with the poly cytokeratin AE1/3. As is common in these tumours the epithelioid areas stain with basal-type markers - in this case CK14 - 'Mouse-over'.
This case raises four important points:
- The differential diagnosis of an atypical spindle cell lesion of the breast includes fibromatosis, phyllodes tumour and spindle cell or metaplastic carcinoma (see links below). Metaplastic carcinoma is the most common.
- There are good morphological pointers in this case away from the first two diagnoses and the heterologous focus helps lead you towards a diagnosis of metaplastic carcinoma.
- The diagnosis of metaplastic carcinoma must be excluded in this scenario. Examine extra levels, put more tissue through if available and look for epithelial differentiation using immunohistochemistry.
- This case is unusual in that the foci of epithelial differentiation were identified ONLY by immuno - there were no epithelioid areas
on H & E morphology - even when going back to the H & E sections having seen the immuno.