Malignant adenomyoepithelioma of the breast: seven cases illustrating morphological diversity and diagnostic challenges.
Sompon Apornvirat, Edward Jaya Hadi, Mihir Gudi et al.
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Case in brief
This retrospective clinicopathological review describes seven women aged 45–74 years with malignant adenomyoepithelioma (M-AME) of the breast. The tumours showed varied combinations of classic and malignant components, including metaplastic spindle or squamous cell carcinoma, invasive patterns, and in situ disease. One atypical adenomyoepithelioma was associated with late lung metastasis and HRAS p.G13R and an in-frame PIK3R1 deletion. The cases illustrate diagnostic overlap with infiltrative-like classic adenomyoepithelioma and metaplastic breast carcinoma. The authors conclude that architectural assessment, supported by immunohistochemical and molecular findings and clinical and radiological correlation, helps classify these lesions.
What made this case unusual
The cases span markedly different morphologies, including in situ M-AME and an atypical adenomyoepithelioma associated with late lung metastasis, highlighting how malignant disease can be difficult to distinguish from classic adenomyoepithelioma and metaplastic carcinoma.
Diagnostic / clinical pearl
Assess the underlying adenomyoepithelioma architecture alongside immunohistochemical and molecular findings; this can help distinguish in situ or invasive M-AME from conventional breast carcinoma arising in an adenomyoepithelioma.
Why it matters
Because these entities overlap morphologically, clinicoradiological and pathological correlation can support classification and help guide appropriate management.