Nodular Mucinosis of the Breast in a Male: Reassessment of Diagnostic Criteria and Proposal for Its Classification as a Soft Tissue Tumor in the Myofibroblastoma and Spindle Cell Lipoma Spectrum

Abstract

Nodular mucinosis of the breast (NMB) is a rare entity with only a few cases described in the literature, most of them in young girls. All cases are located in the nipple and areolar area and microscopically consist of a multinodular myxoid mesenchymal proliferation. Bands of sclerotic collagen containing preexisting breast ducts and abundant vascularization are other features typical of NMB. No relation to Carney complex has been reported, and an indolent behavior is the rule in all patients. We present a case of NMB occurring in the nipple of a 46-year-old man and analyze the clinicopathological features of the other cases of NMB reported in the English literature, concluding that two of them most likely correspond to trauma-induced cutaneous focal mucinosis of the mammary areola. Finally, we review diagnostic criteria for NMB and elaborate an ontogenetic hypothesis based on both its morphological resemblance to myofibroblastoma and its immunohistochemical profile. © 2014 S. Karger AG, Basel

Nodular mucinosis of the breast: A rare entity

“…In terms of treatment, surgical excision is the treatment of choice for NMB. Among the previously reported cases, no recurrence was reported during a follow-up period of 6 months to 6 years [5]. Similarly, our patient also remained recurrence-free during six months of follow-up despite the positive surgical margin.…”

“…Dermatological examination of our patient revealed a 2 cm sized nodule with a firm, rubbery consistency. On clinical grounds alone, it may resemble lipoma, neurofibroma, fibroadenoma, nipple adenoma or epidermal cyst as in the present case [3,5]. Except for the characteristic location, there is no distinctive clinical feature for NMB.…”

“…Nodular mucinosis of the breast (NMB) is an extremely rare condition affecting the nipple-areolar region. It was first defined in 1998 by Michal et al, and few cases have been reported since then [1][2][3][4][5].…”

Nodular Mucinosis of Breast: A Case Report

“…Another proposal is that NM is a soft tissue tumor within the spectrum of myofibroblastoma and spindle cell lipoma, since both myofibroblastoma and spindle cell lipoma share many histologic features, including genetic aberrations [9]. This hypothesis emanates from the immunohistochemical findings of diffuse CD34 and weak but noticeable S-100 immunopositivity of the case.…”

“…It is distinct from myxomas developed in Carney complex. There are 13 reported cases in the English literature [1][2][3][4][5][6][7][8][9]. All the reported cases involve around the nipple of young women, as well as men.…”