Granular cell tumor of the breast

A granular cell tumor (GrCT) of the breast is an uncommon, usually benign tumor which is possibly of neural origin.

Epidemiology

They tend to occur at a younger age than other types of breast cancer ⁴. The age range of presentation, however, can be very variable although they occur more commonly in pre-menopausal women.

Clinical presentation

Clinically they can mimic carcinoma because of their fibrous consistency and their hardness, thus presenting as a palpable mass.

Pathology

GrCTs can occur in a variety of visceral and cutaneous sites. Most authors favor a Schwann cell origin, based on histochemical, immunohistochemical, and ultrastructural findings and on occurrence of typical lesions, within nerves.

The breast accounts of ~5-8% of all granular cell tumors ². Cells with eosinophilic granules with abundant cytoplasm are characteristic. Positive immunohistochemical staining of the cells for S-100 protein, CD68 (KP-1) NSE, and CEA is indicative of this tumor ¹. There is a negative reaction against cytokeratin.

Location

GCTs tend to occur most commonly in the upper inner quadrant corresponding to the cutaneous sensory territory of the supraclavicular nerve.

Radiographic features

Imaging features on both ultrasound and mammography can mimic that of more sinister breast malignancy.

Mammography

On mammography, these tumors can present as an ill-defined or spiculated lesions, similar to primary carcinoma.

Breast ultrasound

On ultrasound, this tumor can appear as a solid, hypoechoic, ill-defined mass, associated with a posterior shadowing, or as a well-circumscribed oval mass, associated with a posterior enhancement, depending on the extent of infiltration and degree of reactive fibrosis.

History and etymology

Granular cell tumors, in general, were first described by A I Abrikosoff in 1926 as a “myoblastic myoma” ⁸.

Treatment and prognosis

Usually, a wide local surgical excision is performed. While less than 1% of tumors are malignant, local recurrences have been reported with incomplete excision.

Differential diagnosis

Considerations include:

• other forms breast malignancy