Mucinous carcinoma of the male breast with axillary lymph node metastasis: Report of a case based on fine needle aspiration cytology.

Pure mucinous carcinoma of the male breast is an uncommon malignant breast neoplasm and extremely rare is its metastasis in axillary lymph nodes. Most of these cases have been diagnosed after surgical resection with only a few cases diagnosed on fine needle aspiration cytology (FNAC). Although FNAC is well established in the evaluation of breast masses in females there are few reports in males. We are presenting a case of pure mucinous carcinoma of the male breast with metastasis in axillary lymph nodes in a 75-year-old male diagnosed by FNAC and confirmed on histopathology.

Introduction

Male breast carcinomas are an unusual form of neoplasm representing 1% of all breast carcinomas.[12] In the literature reviewed we found only eight cases of mucinous carcinoma.[34] Other than mucinous carcinoma various special types such as medullary, tubular, apocrine, adenoid cystic and secretory carcinomas have been reported in the male breast.[3]

Pure mucinous carcinoma of the male breast is an extremely rare histological subtype of malignancy constitutes not more than 0.5% among histological variants and rarer is its metastasis in axillary lymph nodes.[5] This case is reported due to the rarity of the literature of fine needle aspiration cytology (FNAC) diagnosis of mucinous carcinoma of male breast with axillary lymph node metastasis.

Case Report

A 75-year-old male presented with a gradually enlarging right breast mass for the last two years. On clinical examination the mass measured 10 × 9 × 4 cm in size, soft to firm in consistency, with retraction of the nipple and ulceration of the areola with two palpable axillary lymph nodes. Left breast was normal. Systemic examination did not reveal any positive finding.

Patient was advised to undergo fine needle aspiration which was done from the breast mass and lymph nodes using the standard procedure. Aspirate was thick and mucoid in nature. Two slides from each aspirate were prepared and stained with Papanicolaou method. The aspirates were moderately cellular with abundant mucin in the background. Cells were monomorphic, large, with wispy cytoplasm, round to oval eccentric nuclei, regular nuclear membranes and fine chromatin. The cells were arranged in groups and cords [Figure 1].

Figure 1

Smears from breast mass showing abundant mucin and monomorphic large cells with eccentric nuclei (Pap, ×400)

Aspiration from breast lump and axillary lymph nodes revealed the same findings.

A cytological diagnosis of mucinous carcinoma with metastasis in axillary lymph nodes was made and excision of lump was recommended.

We received modified radical mastectomy specimen with axillary lymph nodes, which showed retraction of nipple with large ulcer of size 3 × 2 cm in areola region. Cut surface showed large mucoid, gelatinous mass of size 7 × 6.5 × 3.5 cm. Tumor was well circumscribed reaching up to the skin.

Two lymph nodes were received, of size 3.5 × 2.5 × 2 cm and 3.5 × 3 × 2 cm, soft to firm in consistency, shiny and translucent externally. Cut surface of each showed mucinous gelatinous appearance.

Histopathology revealed malignant cells arranged in groups and cords with pools of mucin in the background. Lymph nodes were totally replaced by tumor and showed similar morphology. Pure mucinous carcinoma of male breast with axillary lymph nodes’ metastasis was confirmed.

Discussion

Male breast carcinoma is an unusual form of neoplasm representing less than 1% of all breast cancer cases.[467] All the microscopic types identified in the female breast have been encountered in the male breast. The most common subtype diagnosed is invasive ductal carcinoma with pure mucinous carcinoma accounting for 0.5%.[68]

Pure mucinous carcinoma is associated with very low incidence (about 2-4%) of nodal metastasis in females.[8] Carcinoma in male breast is hundred times less frequent than in female breast. Radiation exposure, genetic predisposition, chronic liver diseases, and schistosomiasis have been linked to increased incidence of carcinoma in male breast. An association with Klinfelter's syndrome has been noted with 20 times higher frequency.[3-5] There are very few case reports of mucinous carcinomas of male breast with lymph node metastasis and most of them diagnosed after surgical resection.[49] The only Indian case reported on fine needle aspiration cytology is by Nayak et al.,[4] which did not reveal any lymph node metastasis.

In the present case mucinous carcinoma of male breast with axillary lymph node metastasis was reported on FNAC.

Bhagat et al.,[3] in their study of 14 cases of male breast tumors, found only one case of mucinous type which was reported as lobular carcinoma probably due to lack of mucoid background, linear arrangement of malignant cells and minimal nuclear alteration.

Histologically, infiltrating duct carcinoma is the commonest tumor of the male breast similar to the female breast. Visfelldt et al.,[10] found five cases of mucinous carcinoma out of 187 male breast carcinomas studied histologically.

Prognosis in male breast carcinoma is poor, maybe due to the smaller size of breast mass, which increases the probability of the involvement of surrounding structures. Prognosis depends on the stage at diagnosis as determined by tumor size and nodal metastasis.[4] Estrogen receptor and progesterone receptor positivity has been noted in 90% of cases.[56] Pure mucinous carcinoma is associated with a better prognosis and a low rate for axillary lymph node metastases.[11]

The presence of abundant extra-cellular mucin may act as a barrier and diminish the tumor cell burden in mucinous carcinoma at the invasive margins.[9]

In our case, although the patient was a 75-year-old man and the nuclear grade was low, lymph node metastases were already present. The standard treatment of male breast cancer is modified radical mastectomy combined with axillary lymph node dissection.

Although lymph node metastasis of pure mucinous carcinoma is rare, it is important to perform careful clinical examination when the primary breast mass is suspicious for mucinous carcinoma because the presence of lymph node metastasis defines the proper choice of therapeutic strategy.[9]