Male Breast, Stromal Tumors, and Others

Question 1

What is gynecomastia?

Answer 1

• The only benign lesion seen with any frequency in the male breast

Question 2

How does gynecomastia present?

Answer 2

• Button like subareolar enlargement (more common during puberty or very old) that may be bilateral

Question 3

What is the pathogenesis of gynecomastia?

Answer 3

• Estrogen/androgen imbalance that leads to stimulation of breast tissue

Question 4

What is the morphology of gynecomastia?

Answer 4

• Dense collagenous connective tissue and ductal epithelial hyperplasia (no lobule formation)

Question 5

What are some causes for gynecomastia?

Answer 5

• Liver disease
• Drugs
• Decreased testosterone
• Testicular neoplasms
• XXY karyotype

Question 6

What are some risk factors for male breast cancer?

Answer 6

• Similar to those seen in women

Question 7

What is the average age of someone with male breast cancer?

Answer 7

• 60-70

Question 8

What are fibroadenoma and phyllodes tumor?

Answer 8

• Arise from cells of the intralobular stroma
• Biphasic because they include a non-neoplastic epithelial component, the proliferation of which may be stimulated by growth factors elaborated by the stromal cells

Question 9

What are fibroadenomas and phyllodes tumors driven by?

Answer 9

• Somatic mutations in MED12

Question 10

What is fibroadenoma?

Answer 10

• Most common benign tumor of the female breast

- Frequently multiple and bilateral

Question 11

What drug causes a high incidence of multiple, bilateral fibroademonas?

Answer 11

• Cyclosporine A after renal transplantation

- Fibroadenomas regress after treatment cessation

Question 12

How do fibroadenomas present?

Answer 12

• As a well-circumscribed mass on radiograph

- Grossly, a rubbery, white, well-circumscribed mass is clearly demarcated from the surrounding yellow adipose tissue

Question 13

What is phyllodes tumor?

Answer 13

• Most often present as a palpable mass

Question 14

When is the peak age for phyllodes tumor?

Answer 14

• Older than fibroadenoma by 10-20 years

Question 15

How is phyllodes tumor differentiated from fibroadenoma?

Answer 15

• Basis of higher cellularity
• Higher mitotic rate
• Nuclear pleomorphism
• Stromal overgrowth
• Infiltrative borders

Question 16

What do low grade phyllodes tumors resemble?

Answer 16

• Fibroadenomas (but are more cellular and are mitotically active)

Question 17

What is a myofibroblastoma?

Answer 17

• Consists of myofibroblasts and is unusual in that it is the only breast tumor that is equally common in males

Question 18

What is a lipoma?

Answer 18

• Benign fatty tumor

Question 19

What is fibromatosis?

Answer 19

• A mix of fibroblasts and myofibroblasts
• Is an infiltrating mass that can involve the muscle
• Locally aggressive, but does not metastasize
• Due to trauma/surgery or syndromic

Question 20

What is angiosarcoma?

Answer 20

• Malignant stromal lesion
• Occurs sporadically in younger women (average age is 35)
• Prior radiation or in the setting of Stewart-Treves syndrome

Question 21

What are some other cancers that will metastasize to the breast?

Answer 21

• Non-Hodgkin lymphoma
• Burkitt lymphoma
• Malignant tumors that are identical to counterparts found in skin elsewhere
• Mets from melanomas or ovarian cancers

Question 22

What are most primary breast lymphomas?

Answer 22

• B-cell type but a rare T cell lymphoma may arise in association with breast implants (due to chronic inflammation)