Clinical Features

As mentioned, ectopic breast tissue can undergo the same pathologic changes as normal breasts. Cases of ectopic breast with benign cystic changes,[10] benign tumors (adenomas and fibroadenomas),[11,12] and carcinoma are documented.[13] When a mass is located along the milk line, the possibility of the presence of breast tissue should be considered. Such masses, for instance in the axilla, may on initial inspection be mistaken for an enlarged lymph node. A handful of cases of breast carcinoma arising in ectopic vulvar breast tissue have been reported.[14] Such cases can present a challenge for both the clinician and the pathologist in making the correct diagnosis. Supernumerary breasts and nipples for the most part present only a cosmetic problem and may be surgically removed. They also may be removed when causing discomfort due to tenderness or when secreting milk. In cases of carcinoma, wide surgical excisions are recommended, with appropriate follow-up treatment.[15]

Polythelia is linked with abnormalities of the urinary tract. Such abnormalities include supernumerary kidneys, failure of renal formation, and carcinoma of the kidney.[16,17,18] The association of polythelia and renal anomalies is not ironclad but is supported by some studies. A study from Israel[19] reported 40% of children with polythelia had obstructive renal anomalies or duplications of the excretory system. The presence of extra nipples in children should heighten the clinician's suspicion of possible renal anomalies. Nonrenal anomalies can involve the cardiovascular, central nervous, and gastrointestinal systems, in addition to chromosomal abnormalities and genetic syndromes.[20] Cardiovascular problems associated with polythelia include congenital heart anomalies, high blood pressure, and conduction or rhythm disturbances.[18] An association with testicular tumors has been cited.[21] Polythelia associated with familial alcoholism has also been suggested.[22]

Commonly, polymastia and polythelia occur sporadically, but familial cases are reported.[23,24] In families, supernumerary breast tissue can be seen in siblings or across generations. Toumbis-Ioannou and Cohen[24] describe a woman with left-sided polythelia and an ectopic right kidney. Her older sister had left-sided polythelia, and her brother had a complete supernumerary breast on his left side. Klinkerfuss[25] reported on polymastia in four generations of a family.

Most cases of supernumerary breasts and nipples occur within the milk line running from the axilla to the groin. However, there are rare, unusual cases in which they occur elsewhere. Such breasts have been referred to as "mammae erraticae."[3,8] Unusual locations include the buttock, back of neck, face, flank, upper arm, hip, shoulders, and midline of the back and chest.[8,26] A highly unusual case[3] reported in 1980 involved a well-formed mass resembling a female breast on the back thigh in a 74-year-old man (Fig 3). A quote from that article: "He stated that he had this 'fatty tumor' almost all of his life and that it never caused a problem (ie, secreted)."[3] The patient refused removal of the breast. Hollywood has not overlooked breast anomalies. The villain in the James Bond movie The Man with the Golden Gun had a third nipple. A mutant in the Arnold Schwarzenagger movie Total Recall had a third breast mid-sternum.

(Enlarge Image) Figure 3. Supernumerary breast on posterior thigh of 74-year-old man. (Reprinted with permission from Camisa.[3])

Individual cases of polymastia and polythelia are exceptional. The highest number of supernumerary breasts, reported by Neugebauer in 1886,[8(p72)] was eight in addition to the two normal breasts. A report in 1675 described the presence of five nipples on the left breast and two on the right.[8(pp 96,97)] There are numerous reports of infants nursed from supernumerary breasts.[8] An often cited case[8] from 1827 refers to Therese Ventre of Marseilles, France. Her mother had a supernumerary breast beneath her normally positioned right breast. Ventre had a supernumerary breast on the side of her left thigh. This breast enlarged during puberty, and when she became pregnant, it produced milk. It was offered to her infant who took it willingly. She apparently nursed five children during her life from all three of her breasts. Although the woodcut showing children nursing from both her right breast and thigh breast did not accompany the original papers describing this woman's case, it has often been used in reference to her (Fig 4).[27] In a disputed case,[8] a woman who had breasts on her shoulders was said to have drawn them forward beneath her arms to let her children nurse. Other cases[8(p73)] include nursing from breasts located in the groin and nursing from a third breast located in the midline of the chest.