Mammary myofibroblastoma, abbreviated MMFB, is a rare, benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 tumour of the breast

Breast

The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

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Diagnosis

The diagnosis is based on examination under a microscope, by a pathologist. Radiologic

Medical imaging

Medical imaging is the technique and process used to create images of the human body for clinical purposes or medical science...

 findings may be suggestive, as these tumours are well-circumscribed and devoid of calcification

Calcification

Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...

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Pathology

MMFBs consist of bland spindle cells arranged in fascicles with interspersed thick bundles of collagen

Collagen

Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

. They typically stain with CD34

CD34

CD34 molecule is a cluster of differentiation molecule present on certain cells within the human body. It is a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells...

 and desmin

Desmin

Desmin is a protein that in humans is encoded by the DES gene.Desmin is a type III intermediate filament found near the Z line in sarcomeres. It was first described in 1976, first purified in 1977, the gene was cloned in 1989, and the first knock-out mouse was created in 1996. Desmin is only...

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In extra-mammary sites the tumour is known as a mammary-type myofibroblastoma, and may immunohistochemically and histomorphologically overlap with spindle cell lipoma.