You are in: eMedicine Specialties > Dermatology > PEDIATRIC DISEASES Supernumerary NippleArticle Last Updated: Jun 26, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Aryeh Metzker, MD, Consulting Staff, Department of Pediatric Dermatology, Senior Clinical Lecturer, Department of Dermatology, Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University Editors: Mark A Crowe, MD, Assistant Clinical Instructor, Department of Medicine, Division of Dermatology, University of Washington School of Medicine; Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center; Robert A Schwartz, MD, MPH, Professor and Head of Dermatology, Professor of Medicine, Professor of Pediatrics, Professor of Pathology, Professor of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School; Glen H Crawford, MD, Assistant Clinical Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Chief, Division of Dermatology, The Pennsylvania Hospital; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center Author and Editor Disclosure Synonyms and related keywords: accessory nipples, polythelia, SN, polymastia, extra nipples INTRODUCTIONSection 2 of 10
  BackgroundSupernumerary nipples (SNs) are a common minor congenital malformation that consists of nipples and/or related tissue in addition to the 2 nipples normally appearing on the chest. SNs are located along the embryonic milk line. Ectopic SNs are found beyond the embryonic milk line. The embryonic milk line is the line of potentially appearing breast tissue as observed in many mammals. In humans, the embryonic milk line extends bilaterally from a point slightly beyond the axillae on the arms, down the chest and the abdomen toward the groin, and is generally thought to end at the proximal inner sides of the thighs, although SN has been described on the foot.1 SNs can appear complete with breast tissue and ducts and are then referred to as polymastia, or they can appear partially with either of the tissues involved. The classification established by Kajava in 1915 is still valid2:
Although this classification is clear, encountering interchangeable terms and misnomers when dealing with the SN complex is not surprising because of the variability in morphologic patterns. The paucity of descriptions of SNs in medical writings is probably due to its relatively minor clinical significance. However, the subject of SNs has been very popular in the last 2 decades because of the dilemma of possible associated malformations and diseases. The occurrence of SNs has been documented since Roman times and featured in legends and ethnic mythology prior to that time. SNs, and particularly polymastia, were attributed to increased femininity and fertility. Ancient artists depicted the goddess of Artemis of Ephesus and the Phoenician goddess of fertility, Astrate, like other ancient deities, as having row upon row of breasts on their chests.3 Anne Boleyn, the wife of King Henry VIII, was known to have a third breast. SNs in men were a sign of virility and endowed them with divine powers. Nowadays, film stars expose their SNs in the cinema with this same effect.3 The first medical report dates back to 1878 when Leichtenstern estimated the prevalence of SNs to be 1 in 500 (0.2%).4 Associations with other diseases SN features are found in a number of syndromes, but, in most cases, it is probably a chance finding. These syndromes include Turner syndrome, Fanconi anemia, and other hematologic disorders5; ectodermal dysplasia; Kaufman-McKusick syndrome; and Char syndrome. Numerous sporadic publications linked SNs to an association with anomalies or diseases, but such an association is probably only a chance finding. In 1979, Méhes drew attention to the association of SNs and other anomalies.6 The claim that 40% of SNs investigated also had renal involvement was striking. This figure was later corrected to 23-27%.7, 8 The renal involvement was infectious, a malformation, or neoplastic but mainly due to an obstructive disturbance. Other associations of SNs include the following:
Publications concerning renal involvement in the presence of SN In the following decade, numerous publications supported the claim for a close association of SNs and a renal anomaly, but many others could not find evidence to support such an association, which remains controversial.
The eMedicine Pediatrics article Disorders of the Breast may be of interest. PathophysiologySaint-Hilaire in 1836 and Darwin in 1871 advanced the concept of development of the human race from primitive animals; thus, they also considered the SN as an atavistic structure deriving from the milk line of mammals. Similarly, ectopic SN found on the vulva may express an atavistic structure because the breasts of dolphins and whales are in that location, or ectopic SN on the back, the scapula, and the shoulder29, 30, 31 is reminiscent of the nutria and hutia (rodents) with a similar location of the breasts. Between the fourth and fifth weeks of embryogenesis, an ectodermal thickening forms symmetrically along the ventral lateral sides of the embryo. This epidermal ridge extends from the axillary region to the inner side of the thigh to form the embryogenic milk (or mammary) line. During the second and third embryogenic months, the glandular elements of the breasts are formed near the fourth and fifth ribs, with regression of the rest of the thickened ectodermal streaks. In the case of failure of a complete regression, some foci may remain to result in a SN. This can develop into a supernumerary complete breast (polymastia) or into any other SN variant according to the Kajava classification. FrequencyInternationalThe prevalence of SNs varies with different reports. The prevalence is 0.22% in a Hungarian population,6 1.63% in black American neonates,18 2.5% in Israeli neonates,19 4.7% in Israeli Arabic children,32 and 5.6% in German children.27 These variabilities are attributed at least partially to differences in geographic regions, ethnic groups, and methodology, including methods of physical examination, as well as the age groups participating in the studies. SexThe male-to-female ratio differs in various studies, but, most often, the studies show a male predominance as high as 1.7:1. CLINICALSection 3 of 10
History
Physical
CausesFamilial cases were recorded as parent-child transmission, including 1 report of a family who had SNs in 4 successive generations; therefore, autosomal dominant with incomplete expressivity is the accepted transmission of inheritance.35 DIFFERENTIALSSection 4 of 10
Amniocentesis scar Dermatofibroma Hidradenitis Suppurativa Lipomas Lymphadenitis Lymphangioma Macule Monitoring scar Neurofibroma Pigmented nevus Skin tag Warts, Nongenital WORKUPSection 5 of 10
Histologic FindingsThe histologic features of a SN are identical to that of the regular nipple, including hyperpigmentation, slight hyperkeratosis with epidermal thickening, pilosebaceous structure of Montgomery areolar tubercles, smooth muscle bundles typical of the areola, and possible mammary glands and intradermal straight ducts.36 A significant increase in the number of clear cells of Toker has been found in SN tissue, indicating SN may be a precursor of extramammary Paget disease.37 TREATMENTSection 6 of 10
Surgical CareA protruding (or erectile) SN that causes the patient embarrassment can be easily removed surgically, if desired. Alternatively, a single report described removal using liquid nitrogen cryotherapy.38 The removal of polymastia or a complete ectopic SN (with breast) is more involved. ConsultationsA sporadic SN typically does not present an indication for a thorough workup for other malformations. Exceptions are a SN accompanied by additional minor malformations, a prominent ectopic SN, or an established familial SN. In these instances, consultations for ultrasonography and nephrography investigation are indicated, bearing in mind that kidney and urinary tract pathologic findings can be present but silent. FOLLOW-UPSection 7 of 10
PrognosisMost SNs can be ignored; occasionally, a cosmetic blemish occurs. A sporadic SN typically does not present an indication for a thorough workup for other malformations (see Consultations). Patient EducationOnce a SN is diagnosed, inform the parents or the patient concerning its presence and reassure them that it is an insignificant minor anomaly. However, they ought to know that an SN can go through changes like any regular nipple or breast; these changes may be physiological during puberty or pathological, such as inflammation, mastitis, abscess formation, cysts, adenomata, fibroadenoma, carcinoma, melanoma, or Paget disease. MISCELLANEOUSSection 8 of 10
Medical/Legal PitfallsFailure to diagnose an associated malformation of pathological change is a pitfall. Rarely, an SN may be associated with malformations. If an SN is accompanied by additional minor malformations, a prominent ectopic SN, or an established familial SN, then ultrasonography and nephrography investigation are indicated, bearing in mind that kidney and urinary tract pathologic findings can be present but silent. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
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