Discussion: tuberous breast: revised classification and a new hypothesis for its development.

The stimulating article and proposed hypothesis by Costagliola et al. [1] represent another step forward in our attempts to understand and better classify the clinical entity known most commonly as tuberous breast deformity. Since the original description of this entity by Rees and Aston [2] in 1976, a diverse descriptive nomenclature has arisen within the literature [3]. Concomitant with this has been the proposal of numerous surgical approaches for correction of this deformity [3]. In this article, the authors present their evidence for an expansion of the Grolleau et al. [4] classification system initially described in 1999. In addition to Grolleau types 1, 2, and 3 breast, Costagliola et al. [1] newly describe the type 0 tuberous breast typified by a normal base volume but with herniation of breast tissue through the nipple-areolar complex (NAC). Although this is not the first time this minor form of tuberous breast has been suggested, in this article, the authors clearly expound on their hypothesis for the basic pathophysiology behind this entity [1, 5]. With the publication of this study, we currently have two major theories for the development of the tuberous breast deformity in the literature, namely, the constricted ring theory described by Mandrekas et al. [6] and the theory of weakened peri-NAC skin and fascia, as described in this article [1, 5]. Although these two theories may seem to be in apparent opposition, they both provide explanations for features of tuberous breast deformity commonly seen clinically. The constricted ring theory suggests that abnormal development of the superficial thoracic fascia, which invests the nascent mammary tissue, leads to restricted growth of the breast in one or more directions at the time of puberty. Histologic support for this theory, showing aberrant fibrosis in breast tissue taken from operative specimens, has been offered for only two patients [6, 7]. One obvious criticism of this theory is that this ‘‘constricted ring’’ is not always apparent clinically, and whether its absence represents a fundamental flaw in this theory or a milder form of the deformity is unclear. In contrast to this is the ‘‘weakened NAC skin and fascia’’ theory, supported by Costagliola and others [1, 5]. According to this theory, the causative aberrancy is a weakening within the NAC fascia, which leads to herniation of tissue through the NAC as the breast develops. Theoretically, this may be able to explain the relative loss of breast volume in the lower pole of the tuberous breast seen in more severe forms as well as the isolated milder form of the deformity (i.e., Costagliola type 0) described in this article. Again, limited histologic evidence has been presented in support of this theory [1, 5]. One apparent issue with the authors’ claim that NAC herniation is the sine qua non of the tuberous breast deformity is that it is not seen in all patients presenting with this entity. This has been previously shown by Meara and others [2, 3, 8]. For this reason, Meara et al. [8] excluded concerns with the NAC from their proposed classification system. The authors explain this T. A. Imahiyerobo J. A. Ascherman (&) Division of Plastic Surgery, Columbia University Medical Center, 161 Fort Washington Ave., Suite 509, New York, NY 10032, USA e-mail: jaa7@columbia.edu