Authors: Wegner U, Juette A, Ryan AG, Daly CA.
Purpose and Objectives: Granular-cell tumor is one of the rarest breast lesions and can be mistaken for malignancy on imaging. Distinguishing it histologically from all other breast malignancy mimics, the tumour has an exceptional origin from perineural cells. We report the imaging of a premenopausal patient, illustrating the sonographic and mammographic features, in combination with a review of the literature.
Case Report: A 46- year old premenopausal female of African origin with a two month history of a painless hard breast mass was referred for further assessment, imaging evaluation and biopsy. On physical examination, the lesion was located at the 12 o’clock position, measured 2.8 cm and had an irregular surface. Ultrasound showed features consistent with malignancy i.e. the mass was taller than wide, was non-compressible and demonstrated posterior acoustic shadowing, and was therefore assigned BI-RADS 5. No associated findings such as skin thickening, hypervascularity or oedema were evident. There was no axillary lymphadenopathy. Histopathology of a core biopsy revealed a diagnosis of Granular Cell Tumor of the breast and no evidence of malignancy. Granular Cell Tumors of the breast are very rare, firm breast lesions of neural Schwann cell origin (in this case from the supraclavicular nerve). Complete excision of the tumor is recommended as there may be less than a 1% risk of malignant transformation; however, recurrence and metastases are very unlikely and thus only routine patient follow-up is required.
Conclusion: Familiarity with this rare entity prevents unnecessarily radical surgery once the diagnosis is confirmed by prompt biopsy.
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