Apocrine cystadenoma, apocrine hidrocystoma, and eccrine hidrocystoma: three distinct tumors defined by expression of keratins and human milk fat globulin 1

Abstract

Eccrine hidrocystomas and apocrine cystadenomas are morphologically related cystic sweat gland tumors. To elucidate their cellular differentiation we examined by immunohistochemistry the expression of keratins and of human milk fat globulin 1 in 12 of each of these tumors, diagnosed using established conventional histological criteria. All tumors diagnosed as apocrine cystadenomas by these criteria were characterized by a keratin pattern of secretory type. In addition, they expressed human milk fat globulin 1. Tumors diagnosed as eccrine hidrocystomas expressed a keratin pattern of excretory type. A part of the tumors with an excretory keratin pattern expressed human milk fat globulin, while others did not. Some presumed eccrine hidrocystomas expressed the very same antigens as apocrine cystadenomas. Thus, our study reveals three distinct types of tumors, in contrast to the conventional distinction of only eccrine hidrocystomas and apocrine cystadenomas. Apocrine cystadenomas differentiate towards the secretory coil of apocrine sweat glands. Presumed eccrine hidrocystomas may represent cystic tumors of the eccrine sweat duct, or they may represent cystic tumors of the apocrine duct. Thus, the name hidrocystoma should be used without further specification of an eccrine or apocrine nature, unless certainty is reached by immunohistochemical characterization. Also, hidrocystomas often prove to be histologically misdiagnosed apocrine cystadenomas because of a flattened cyst wall secondary to increased intraluminal pressure.

Apocrine Hidrocystoma of the Lower Lip: A Case Report and Literature Review

“…(2) Morphologically, apocrine -HCs have a double lining of epithelium (inner layer, tall columnar or cuboidal cells) with decapitation secretion and an outer side consisting of myoepithelial cells, whereas eccrine -HCs are lined by flat epithelium without myoepithelial cells [3,12]. (3) Immunohistochemically, apocrine -HCs are positive for human milk fat globules, GCDFP-15, CK7 and CK18 in the inner layer of epithelium, and also positive for a-SMA in the outer myoepithelial cells, whereas eccrine -HCs are negative for all of these [3,4,14,15]. Therefore, the most compatible pathological diagnosis in the present case was apocrine -HC.…”

“…Histologically, apocrine -HC can be differentiated from eccrine -HC by the presence of secretory cells showing decapitation secretion. Immunohistochemically, apocrine -HC is positive for human milk fat globules, GCDFP-15, CK 7 and a-SMA, whereas eccrine -HC is negative for all of them [3,4]. Apocrine -HC expresses a secretory-type keratin pattern, whereas eccrine -HC expresses an excretory-type keratin pattern [3].…”

“…Immunohistochemically, apocrine -HC is positive for human milk fat globules, GCDFP-15, CK 7 and a-SMA, whereas eccrine -HC is negative for all of them [3,4]. Apocrine -HC expresses a secretory-type keratin pattern, whereas eccrine -HC expresses an excretory-type keratin pattern [3]. These lesions are usually located on the face and neck, mainly the periorbital area.…”

“…However, apocrine -HC developing on the lower lip is very rare, and clinico-pathologically problem point is differential diagnosis between dermal sweet gland lesion and minor salivary gland lesion in this site. Previous reports of apocrine-and eccrine -HCs affecting the lip are listed in Table 1 [3,5,6]. In fact, the English literature contains very little information on HCs of the lip [3,5,6].…”

“…Previous reports of apocrine-and eccrine -HCs affecting the lip are listed in Table 1 [3,5,6]. In fact, the English literature contains very little information on HCs of the lip [3,5,6]. …”