Breast
Congenital anomalies
Supernumerary / accessory tissue
Author: Hind Warzecha, M.D.
Last author update: 1 February 2010
Last staff update: 29 November 2022 (update in progress)
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Supernumerary nipples or breasts / accessory glandular tissue
Table of Contents
Definition / general | Terminology | Drawings | Epidemiology | Sites | Clinical features | Case reports | Treatment | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosisCite this page: Warzecha H. Supernumerary / accessory tissue. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/breastsupernumerary.html. Accessed February 6th, 2023.
Definition / general
- Persistent epidermal thickenings along milk line from axilla to perineum / vulva, due to clusters of primordial breast cells that fail to involute
- Ectopic tissue may be combinations of breast glandular tissue and nipple
- References: eMedicine: Supernumerary Nipple [Accessed 20 August 2018]
Terminology
- Also called pseudomamma
- Polythelia (3+ nipples) is more common than polymastia (ectopic breast tissue)
Drawings
Images hosted on other servers:
Milk lines
Epidemiology
- Occurs in 2 - 6% of females and 1 - 3% of males
Sites
- Accessory nipples: thorax or abdomen (65%) and axilla (20%) are most common; back, buttock, face and neck are less common
- Accessory glandular tissue: axilla most common
- May be more common on left side in males (Eur J Pediatr 1998;157:821)
Clinical features
- Usually sporadic, can be familial (6%)
- Often not noticed until pregnancy
- Classified into 8 levels of completeness (Wikipedia: Supernumerary Nipple [Accessed 20 August 2018], eMedicine: Breast Embryology [Accessed 20 August 2018])
- May undergo same disease or physiologic processes as other breast tissue, including lactation (J Reprod Med 1994;39:657)
- Associated with renal disease in some studies (7% vs. 1% in controls, Int J Dermatol 1996;35:349, Scand J Urol Nephrol 2009;43:47 but not all, Pediatr Dermatol 2001;18:291)
- Also associated with hematologic disorders (Pediatr Hematol Oncol 2004;21:461), mitral valve prolapse (Am J Cardiol 2000;86:695)
Case reports
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Disease in supernumerary nipples or breast:
- Carcinoma in vulva (Cancer 1976;38:2570)
- Fibroadenoma (J BUON 2007;12:285)
- Hamartoma (Breast 2006;15:135)
- Metaplastic carcinoma (South Med J 2002;95:462)
- Mucinous adenocarcinoma of vulva (Arch Pathol Lab Med 2002;126:1216)
- Paget disease (Virchows Arch 1998;432:289)
- Secretory carcinoma (Arch Pathol Lab Med 2001;125:1372)
- Face (J Pediatr Surg 1997;32:1377)
- Foot (Dermatol Online J 2006;12:7, eScholarship: Pseudomamma on the Foot: An Unusual Presentation of Supernumerary Breast Tissue [Accessed 20 August 2018])
- Male perineum (Urology 1997;50:122)
- Occurrence in three generations (Eur J Pediatr 2001;160:375)
Unusual sites:
Other case reports:
Treatment
- Usually no surgery
- Surgery performed for cosmetic reasons or if a lesion has developed in the breast tissue
Clinical images
Images hosted on other servers:
Neonate
Adolescent boy
Adolescent girl (bilateral)
Nipples anterior to axilla
Nipple on shoulder
Nipple on foot
Microscopic (histologic) description
- Supernumerary nipple has same features as regular nipple, including hyperpigmentation, slight hyperkeratosis, pilosebaceous structure of Montgomery tubercles, smooth muscle, Toker cells (J Cutan Pathol 2003;30:256), possibly breast lobules and ducts
Microscopic (histologic) images
Images hosted on other servers:
12 year old girl with axillary mass
Differential diagnosis
- Lentigos and melanocytic nevi: have melanocytic nests; no pilosebaceous structure of Montgomery tubercles, no smooth muscle organized as with nipple, no Toker cells and no breast glandular tissue
