Case 3 Clinical history A female of 54 years presented to the Breast Clinic with an ill defined lump in the upper outer quadrant of the right breast. No abnormality was seen on imaging and there was a palpable mass, suspicious of malignancy. Fine needle aspiration cytology (FNAC) revealed a benign sample - C2. A diagnostic excision biopsy was therefore performed. Histological appearances - A-C Sections from the biopsy reveal a diffuse collection of small, rounded tubular structures infiltrating into stromal and adipose tissue, together with some essentially normal lobular structures. Nuclei are small and regular, with no discernible difference between the two elements. Immunostaining with anti-smooth muscle actin shows that the tubules lack a myoepithelial layer. Differential diagnosis Microglandular adenosis Tubular carcinoma The features which favour a diagnosis of microglandular adenosis are as follows: · Diffuse pattern - no stellate structure (NB, care needs to be taken in interpreting the sclerosing type of tubular carcinoma). · Lack of desmoplastic and elastotic stroma. · Lack of angulation of tubules. · Regularity of nuclei and similarity to those in adjacent normal nuclei. NB Demonstration of the absence of a myoepithelial layer is unhelpful since this is a feature of both entities. Final Diagnosis Microglandular adenosis Learning points · Microglandular adenosis may mimic tubular carcinoma. · Overall architectural pattern is the most useful distinguishing feature. · Immunostaining with anti-smooth muscle actin is usually unhelpful. |
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| Organisation: FORPATH asbl  |
Coordination: Dr Bernard Van den Heule |
Host: Labo CMP |