Nodular fasciitis of the breast: report of a case initially diagnosed by fine needle aspiration cytology

BACKGROUND: Nodular fasciitis is a rare benign pseudosarcomatous proliferation of fibroblasts in the breast, in which the clinical examination and mammographic findings may closely mimic mammary carcinoma. CASE: A case of nodular fasciitis was diagnosed by fine needle aspiration. A 15-year-old girl was admitted to our hospital with a recently noticed, rapidly growing mass in the right breast. The aspirate contained cohesive groups of fusiform cells with elongated and oval nuclei, regular nuclear membranes and inconspicuous nucleoli, intermingled with scattered lymphocytes, red blood cells and characteristic granular background substance. A cytologic diagnosis of nodular fasciitis was made and confirmed histologically. CONCLUSION: Mammary nodular fasciitis is often clinically suspicious for carcinoma and rarely diagnosed by fine needle aspiration cytology. A literature search yielded only five reported cases. The cytologic diagnosis of this entity helps to choose the correct surgical procedure, preventing psychological trauma to the patient.