PMC7691944_01
Invasive pleomorphic lobular carcinoma (ILC) with extracellular mucin. (A)
The mucinous component comprised approximately 10% of the core needle biopsy
(CNB) (hematoxylin-eosin, original magnification x100). (B) High-grade
nuclei and increased mitotic activity consistent with pleomorphic ILC in an
area of the CNB with intra- and extracellular mucin (hematoxylin-eosin,
original magnification x400). (C) There were foci with a linear pattern of
infiltration in the non-mucinous component in the CNB (hematoxylin-eosin,
original magnification x400). (D) Negative E-cadherin stain with positive
internal control in the CNB (E-cadherin, original magnification x400). (E)
Strong, diffuse staining for ER in the CNB (ER, original magnification
x400). (F) Equivocal staining for HER2 in the CNB (FISH was amplified)
(HER2, original magnification x400). (G) The residual tumor in the
mastectomy did not show a mucinous component (hematoxylin-eosin, original
magnification x400). (H) Negative E-cadherin stain with positive internal
control in the mastectomy (E-cadherin, original magnification x400).
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PMC7691944_01_10.1177_1178223420976383-fig1.jpg
fig1-1178223420976383
Histologic examination of the core needle biopsy of the 15-mm mass demonstrated pleomorphic ILC with extracellular mucin (Figure 1). Histologic examination confirmed pleomorphic ILC with a high combined histologic grade, similar to the prior core needle biopsy (Figure 1).