A Rare Sweat Gland Tumour- Immunohistochemical Features

MIHAELA-CRISTINA PRODEA1, FLORICA SANDRU2*, ECATERINA CARPENCO3, PUSA NELA GAJE4, IOANA DELIA HORHAT1, AMALIA RALUCA CEAUSU4, NARCISA MEDERLE5, OVIDIU ALEXANDRU MEDERLE4,6 1Victor Babes University of Medicine and Pharmacy, Department of ENT, 2 EftimieMurgu Sq., 300041, Timisoara, Romania 2Carol Davila University of Medicine and Pharmacy, Department of Dermatovenerology, Elias Emergency University Hospital, 8 Eroii Sanitari Blvd., 050471, Bucharest, Romania 3N. Testemitanu University of Medicine and Pharmacy, Department of Histology, 165 Stefan cel Mare si Sfant Blvd., MD-2004, Chisinau, Republica Moldova 4Victor Babes University of Medicine and Pharmacy, Department of Microscopic Morphology/ Histology, Angiogenesis Research Center Timisoara, 2 Eftimie Murgu Sq., 300041, Timisoara, Romania 5Banat’s University of Agricultural Sciences and Veterinary Medicine King Michael I of Romania, Parasitology/Mycology Department, 119, CaleaAradului, 300645, Timisoara, Romania. 6Municipal County Hospital, Emergency Department, 24 Gh. Dima Str., 300079, Timisoara, Romania

The main types of normal sweat glands are eccrine and apocrine. The papillary eccrine adenoma is a rare, benign, sweat gland tumor. The clinical aspect is a slow growing solitary dermal nodule on the extremities, less frequently involving the trunk or face. Here it was described a case of papillary eccrine adenoma developed in the scapular-humeral region in a 72 years old man. The K5+/K7+/K8/18+/ K19+/ SMA+/ S100+ immunohistochemical profile and the morphological aspects support the diagnostic of papillary eccrine adenoma. The immunohistochemical profile is useful for the differential diagnostic and may increase the diagnosis accuracy.
Two types of normal sweat glands can be identified: eccrine and apocrine. The first type is distributed over the entire skin surface and open to the epidermis. Apocrine glands are found in the axilla, mons pubis, perianal and periareolar regions, and open to the follicular infundibulum. The sweat glands are composed of 3 segments: the intraepidermal(eccrine)/intrainfundibular (apocrine) duct, the intradermal duct, and the secretory portion. The secretory portion of eccrine glands has a narrow tubular structure composed of pale inner secretory cells and outer myoepithelial cells, whereas apocrine glands shows large tubules composed of eosinophilic secretory cells and peripheral myoepithelial cells [1].
Rulon and Helwig [3,4] described for the first time, in 1977, the papillary eccrine adenoma as a rare, benign, sweat gland tumor. The commonly clinical aspect is a slow growing solitary dermal nodule on the extremities, less frequently involving the trunk or face.
We described here a case of papillary eccrine adenoma that developed in the scapular-humeral region in a 72years oldman.

Experimental part
A 72-year-old manpresented with an ulcerated nodular tumor on the left scapular-humeral region. The lesion measured 2-3 cm in diameter. The patient had a simple excision of the nodule.
Morphological staining showed nodular proliferation with uniform cells. Minor atypia was noticed. The papillary projections were found in the inner part of the nodules. A slightly acidophilic secretion, which in some areas suggests aberrant sebum storage was noticed. Focal hyalinized zones were present. Some of the morphological features are showed in the figures 1 and 2. Immunohistochemical staining revealed the following cytokeratin profile: K5+/ K7+/ K8/18+/K19+/ K20-. Keratin 5 was expressed in the basal cells with granular cytoplasmic pattern. Keratin 7 was intense positive, with luminal profile (fig. 3). K8/18 was intensely expressed in the glandular proliferation ( fig. 4, 5). Keratin 19 had a homogeneous distribution pattern, with moderate intensity ( fig. 6).
Chromogranin A was negative. Ki 67 nuclear expression indicate a proliferative rate between 5-6%. The immunohistochemical features are showed in the figure 3,4.
A high number of mast cells in the interlobular stroma of the tumor and few cells in the intralobular stromawas found ( fig. 7, 8). The immunohistochemical pattern was granular cytoplasmic. S100 was positive in the proliferative and periglandular cells ( fig. 11). Smooth muscle actin expression was noticed intralobular, around glandular structure. Myoepithelial cells were positive, with cytoplasmic expression ( fig. 7, 8).A high number of mast cells in the interlobular stroma of the tumor and few cells in the intralobular stroma was found

Results and discussions
The term tubulopapillaryhidradenoma describes benign sweat gland tumors, characterized by combining ductal as well as apocrine and eccrine glandular differentiation which include both papillary eccrine adenoma and tubular apocrine adenoma [5]. Tubular apocrine adenoma usually presents on the scalp as superficial dermal nodule and shares the histological features of papillary eccrine adenoma, except that the latter has a peripheral myoepithelial cell layer. The S100+/ CEA+/ EMA+ phenotype indicated eccrine origin of papillary eccrine adenoma. In our case, the K5+/K7+/K8/18+/ K19+/ SMA+/ S100+ immunohistochemical profile together with the morphological aspects support the diagnostic of papillary eccrine adenoma.
Around 50 cases of papillary eccrine adenoma were reported in the English Literature so far [6]. It was showed that papillary eccrine adenoma occurs between 9-78 years [7]. Our case, 72 years old man falls within this age range, but doesn't respect the preferred occurrence in women, with a ratio male to female 7:27.
The differential diagnostic can be made with other benign tumours or with aggressive types of neoplasm. In the first category, the immunohistochemical profile (K5+/ K7-/K8/18+/ K19-/K20-/ S100-) may indicates a sebaceous origin of adenoma. The tubular apocrine adenoma is characterized by: localization frequently on the scalp, decapitation secretion, shorter papillary projections into the lumen, lack connections with epidermis, the presence of plasma cells and tendence to co-occur with syringocystadenomapapilliferum [8].
For the second category, the differential diagnosis may include the adenocarcinomas and basal cell carcinoma of eccrine differentiation. The main characteristics of adenocarcinomas are: atypical mitosis, pleomorphism, vascular and perineural invasion, tendency for local recurrence [9]. The similarities between papillary eccrine adenoma and basal cell carcinoma of eccrine differentiation are: tubules consisting of one or two layers of cuboidal cells, surrounded by fibrous stroma, intraluminally eosinophilic granular material. These carcinomas consist cystic, alveolar and cribriform zones and had an aggressive potential. Unlike the papillary eccrine adenomas, the carcinomas didn't contain intracysticpapillations [10].

Conclusions
Despite of typical histological features of this slow growing benign tumour, it can resemble other cutaneous neoplasms. It can be associated with diagnostic challenges and immunohistochemistry profile-K5+/ K7+/K8/18+/ K19+/SMA+/ S100+ may increase the diagnosis accuracy.