Case of the month - March 2007 - discussion

Diagnosis - DCIS with possible pseudoinvasion

• The focus of possible invasion is difficult to interpret because of its close proximity to the core biopsy needle track



• Favouring true invasion is the absence of a myoepithelial population in the suspicious areas



• Features against true invasion include the small size of the whole lesion (5mm) and the obvious proximity of a biopsy track which is healing and shows a foreign body giant cell reaction



• Ultimately it was not possible to resolve this diagnostic problem with certainty



• The case was discussed at a multidisciplinary meeting and a diagnosis of 'possible microinvasion' was made