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Leiomyoma

Author: Reena Tomar, M.B.B.S., M.D.

Editorial Board Member: Julie M. Jorns, M.D.

Deputy Editor-in-Chief: Gary Tozbikian, M.D.

Last author update: 18 January 2024

Last staff update: 18 January 2024

Copyright: 2002-2024, PathologyOutlines.com, Inc.

PubMed Search: Breast leiomyoma

Table of Contents

Cite this page: Tomar R. Leiomyoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastleiomyoma.html. Accessed December 25th, 2024.

Definition / general

Benign mesenchymal tumor of smooth muscle, rare in breast (BMC Womens Health 2022;22:119, J Cutan Pathol 2019;46:343)

Essential features

Benign smooth muscle tumor
Spindle shaped cells with cigar shaped nuclei arranged in whorls and fascicles
SMA, desmin, caldesmon positive

Epidemiology

Middle aged women (BMC Womens Health 2022;22:119)
F:M = 3:1 (Case Rep Surg 2013;2013:475215)

Sites

Rare in breast (1% of breast neoplasms) (Eur J Breast Health 2017;13:156)
Superficial (nipple areola complex) or deep (breast parenchyma)
Subareolar area (Eur J Breast Health 2017;13:156)
Nipple (Case Rep Surg 2013;2013:475215)
More common in other sites such as uterus, gastrointestinal tract, skin and lower extremities (J Oral Maxillofac Pathol 2013;17:281)

Pathophysiology

Arises from smooth muscles (J Cutan Pathol 2019;46:343)
Hormonal association (J Oral Maxillofac Pathol 2013;17:281)

Etiology

Trauma (J Med Case Rep 2013;7:49)
Tamoxifen and antiobesity drug use associated with enlargement of breast leiomyoma (AJR Am J Roentgenol 2005;185:1595)

Clinical features

Typically a firm, mobile lump but can be nonmobile (Breast J 2020;26:529)
Intermittent pain (Case Rep Surg 2013;2013:475215, Breast J 2020;26:529)
No nipple discharge (Case Rep Surg 2013;2013:475215)

Diagnosis

Can be detected on mammography or ultrasound (AJR Am J Roentgenol 2005;185:1595, Korean J Radiol 2020;21:955)
Excisional biopsy is diagnostic as well as therapeutic due to risk of local recurrence (Int J Sci Stud 2015;3:210, J Med Case Rep 2013;7:49)

Radiology description

Ultrasound shows an oval, circumscribed hypoechoic mass with internal vascularity (Korean J Radiol 2020;21:955)
MRI scan reveals an intense, homogeneous enhancement (Korean J Radiol 2020;21:955)
Well defined lesion, hypoechoic on mammography (AJR Am J Roentgenol 2005;185:1595)
No calcifications (Eur J Breast Health 2017;13:156)

Radiology images

Images hosted on other servers:

Well defined, circumscribed, hypoechoic mass

Case reports

31 year old woman with enlarging hard lesion in bilateral nipple (Case Rep Surg 2013;2013:475215)
40 year old woman with mass in right nipple (Breast J 2020;26:529)
43 year old woman with bilateral breast lump with atypical features and 46 year old woman with a 3 cm lesion in left breast (BMC Womens Health 2022;22:119)
44 year old woman with painless lump in right breast (Eur J Breast Health 2017;13:156)
47 year old woman with a 2 cm mass in sonography of left breast (AJR Am J Roentgenol 2005;185:1595)
59 year old woman for routine mammography (Radiol Bras 2016;49:343)

Treatment

Excisional biopsy is therapeutic (J Med Case Rep 2013;7:49)
Calcium channel blocker, alpha adrenergic blocker may be used to reduce pain (Case Rep Surg 2013;2013:475215)

Clinical images

Images hosted on other servers:

1 cm nodule (black arrow) on left areola

Left nipple (white arrow), nodule (black arrow)

Swollen left nipple compared with the right nipple

Gross description

Circumscribed (Breast J 2020;26:529)
0.8 - 2.7 cm in size (Breast J 2020;26:529)
Fleshy, pale, whitish (Eur J Breast Health 2017;13:156)
Homogenous white cut surface (Breast J 2020;26:529)

Gross images

Images hosted on other servers:

Well circumscribed skin covered mass

Frozen section description

Frozen section has been described to evaluate margins (Case Rep Surg 2013;2013:475215)

Frozen section images

Contributed by Reena Tomar, M.B.B.S., M.D.

Scrapes

Scrapes (toluidine blue)

Microscopic (histologic) description

Proliferation of monotonous spindle cells (BMC Womens Health 2022;22:119)
Spindle cells are relatively uniform in size and shape with cigar shaped nuclei (Breast J 2020;26:529)
Interlacing bundles of smooth muscle cells separated by a small amount of well vascularized connective tissue (J Med Case Rep 2013;7:49)
Circumscribed, overlying epidermis is unremarkable (Breast J 2020;26:529)
Nipple leiomyoma shows dermal lesion, glandular components are absent
No mitosis, no necrosis, no atypia (BMC Womens Health 2022;22:119)
Atypical leiomyoma has features of nuclear atypia and up to 3 mitosis/10 high power fields (BMC Womens Health 2022;22:119)

Microscopic (histologic) images

Contributed by Reena Tomar, M.B.B.S., M.D., Mark R. Wick, M.D. and Julie M. Jorns, M.D.

Dermal circumscribed leiomyoma

Spindle shaped cells

Fascicles

Whorls and fascicles

SMA

Caldesmon

Desmin

S100

Fascicles

Breast core biopsy

Positive stains

SMA (Breast J 2020;26:529)
Desmin (Breast J 2020;26:529)
HHF35 (Breast J 2020;26:529)
Caldesmon (Breast J 2020;26:529)
Ki67 5% in atypical leiomyoma (BMC Womens Health 2022;22:119)
ER, PR (EJMED 2023;5:26)
Vimentin (Radiol Bras 2016;49:343)

Negative stains

S100 (Radiol Bras 2016;49:343)

Sample pathology report

Right breast (nipple), punch biopsy:
- Nipple leiomyoma (see comment)
- Comment: There is a circumscribed dermal proliferation of monotonous spindle cells. On immunohistochemistry, spindle cells are positive for SMA and desmin and negative for S100 and CK, supporting the diagnosis.

Differential diagnosis

Leiomyosarcoma (EJMED 2023;5:26, BMC Womens Health 2022;22:119):
- Atypical features, pleomorphism, mitosis and necrosis are seen
Phyllodes tumor (Eur J Breast Health 2017;13:156):
- Biphasic epithelial and stromal neoplasm
- Stromal cellularity and stromal overgrowth with atypia, necrosis and mitosis in borderline and malignant phyllodes
Nipple adenoma:
- Florid benign epithelial (glandular or squamous) proliferation with intact myoepithelium throughout
- May have papillary architecture
- Connected to the epidermis
Adenomyoepithelioma (Eur J Breast Health 2017;13:156):
- Biphasic with glandular and myoepithelial components
- Myoepithelial prominence
Nodular fasciitis (BMC Womens Health 2022;22:119):
- Fibrous proliferation, variably loose, tissue culture-like to more collagenized stroma
- Negative for desmin
Myoid hamartoma (J Med Case Rep 2013;7:49):
- Biphasic benign proliferation with glandular and stromal components with prominent smooth muscle
- Within stromal component, glandular components are also seen; this is absent in leiomyoma

Board review style question #1

A 35 year old woman presents with a freely mobile lump in the nipple areolar area of the left breast. Microscopy shows features in image above with no mitosis or atypia. Which of the following immunohistochemical markers is best to confirm and highlight the diagnosis?

CK72
Ki67
S100
SMA

Board review style answer #1

D. SMA highlights smooth muscle origin. Answer A is incorrect because CK72 is an epithelial marker. Answer C is incorrect because S100 is a neural marker. Answer B is incorrect because Ki67 is a proliferation marker that will be low in benign leiomyoma but will not help in diagnosis.

Comment Here

Reference: Leiomyoma

Board review style question #2

Which of the following is typically true about breast leiomyoma?

Has nipple discharge
Has no hormonal association
Is imaging occult
May be painful

Board review style answer #2

D. May be painful. Nipple adenomas may be painful, which may be alleviated by calcium channel or alpha adrenergic blockers that cause smooth muscle relaxation. Answer C is incorrect because breast leiomyoma may be seen as a mass on breast imaging modalities such as mammogram and ultrasound. Answer B is incorrect because breast leiomyomas are associated with hormonal agents. Answer A is incorrect because breast leiomyoma has not been associated with nipple discharge.

Comment Here

Reference: Leiomyoma

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