Axillary apocrine carcinoma with benign apocrine tumours: a case report involving a pathological and immunohistochemical study and review of the literature

Abstract

Background: Apocrine carcinoma is rare and often occurs in the axilla. This is the second apocrine carcinoma arising in bilateral axillae with associated apocrine hyperplasia to be reported.

Aims/methods: Because benign apocrine tumours may be precursors of cancer, this case was investigated immunohistochemically and histologically, and a literature (English and Japanese) review undertaken of cases with coexistent malignant and benign apocrine tumours in the axilla to elucidate the relation between apocrine carcinoma and benign apocrine tumours.

Results: Only four cases of axillary apocrine carcinoma with benign apocrine tumours were identified in the literature. In each case, benign apocrine hyperplasia was situated within and surrounding the adenocarcinomatous nests. Staining for epithelial membrane antigen revealed three patterns: (1) poorly differentiated tumour cells showing strong cytoplasmic staining; (2) combined luminal surface and cytoplasmic staining of glandular cells; and (3) a strongly positive lineal staining pattern at the luminal membrane surface, comprising one or two apocrine hyperplastic secretory cells. The basal lesions of apocrine hyperplasia were strongly positive for alpha smooth muscle actin, whereas the periphery of adenomatous lesions showed weaker positive staining, even though the periphery of adenocarcinomatous lesions was negative.

Conclusions: All five apocrine carcinomas with benign apocrine tumours occurred in elderly Japanese men who had bilateral benign apocrine tumours even if affected by unilateral axillary apocrine carcinoma. The immunohistochemical results support the notion that apocrine hyperplasia is a precursor of cancer and that apocrine carcinoma, adenoma, and hyperplasia may be successive steps in the linear progression to carcinoma.

Figure 1

Gross view of the right axillary tumour resected in December 2002. (A, B) Tumour nests are gathered in the centres and show variation from solid coalescent nests within and surrounding the centre. Some lobular masses are within and spread around the centre.

Figure 2

(A) The tumour cells of the centre exhibit papillary adenocarcinoma with varying degrees of differentiation, contain abundant eosinophilic cytoplasm, and show apocrine-like decapitation. (B) In poorly differentiated areas, the tumour cells form strands or solid nests within a hyalinised fibrous stroma in the upper dermis. (C) The cells within and surrounding the centre contain gland forming regions with several layers of lining epithelial cells, indicating the presence of apocrine adenoma. (D) The luminal layers of the lobular masses are composed of cuboidal or columnar secretory cells without atypicality and a dilated lumen, which contain eosinophilic secreted material with occasional calcification. Haematoxylin and eosin stain; original magnification, ×33.

Figure 3

(A, B) The adenocarcinomatous lesions are negative for α smooth muscle actin (αSMA), although (C) the peripheral areas of the adenomatous lesions are weakly or moderately positive. (D) The basal lesions of apocrine hyperplasia show strong positive staining for αSMA.

Figure 4

(A, B) The cytoplasm of the papillary adenocarcinoma cells and the poorly differentiated tumour cells was strongly positive for epithelial membrane antigen (EMA). (C) The luminal surface and the cytoplasm of the glandular cells showed the same degree of positive staining for EMA. (D) The luminal membrane surface, composed of one or two secretory cells, also showed strong positive staining for EMA.