Recurrent Myopericytoma of the Breast Mimicking Phyllodes Tumour: A Diagnostic and Management Challenge.
Purnima Paliwal, Sai Jyoti, Neha A Singh et al.
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Case in brief
A 37-year-old woman presented with a recurrent left breast mass whose clinical and radiological features suggested phyllodes tumour. Histology showed a spindle cell neoplasm with concentric perivascular growth, focal necrosis, brisk mitotic activity, and infiltration into adjacent breast tissue. Smooth muscle actin and vimentin positivity supported myopericytoma; the Ki-67 index was 15%-20%. The short-interval recurrence and invasive, mitotically active features raised concern for malignant myopericytoma. The report emphasizes that careful histologic and immunophenotypic assessment was needed to establish the diagnosis and inform surgical management.
What made this case unusual
Myopericytoma is typically found in the extremities, and this report describes a breast lesion that clinically and radiologically mimicked phyllodes tumour, with recurrence and invasive, mitotically active features raising concern for malignancy.
Diagnostic / clinical pearl
In a breast spindle cell neoplasm, concentric perivascular growth and supportive immunophenotyping can help distinguish myopericytoma from more common spindle cell tumours, including phyllodes tumour.