TRPS1 Is Differentially Expressed in a Variety of Malignant and Benign Cutaneous Sweat Gland Neoplasms

Abstract

Neoplasms of sweat glands and the breast may be morphologically and immunophenotypically similar. A recent study showed that TRPS1 staining is a highly sensitive and specific marker for breast carcinoma. In this study, we analyzed TRPS1 expression in a spectrum of cutaneous sweat gland tumors. We stained five microcystic adnexal carcinomas (MACs), three eccrine adenocarcinomas, two syringoid eccrine carcinomas, four hidradenocarcinomas, six porocarcinomas, one eccrine carcinoma-NOS, 11 hidradenomas, nine poromas, seven cylindromas, three spiradenomas, and 10 syringomas with TRPS1 antibodies. All of the MACs and syringomas were negative. Every cylindroma and two of the three spiradenomas demonstrated intense staining in cells lining the ductular spaces, with negative to relatively weak expression in surrounding cells. Of the 16 remaining malignant entities, 13 were intermediate to high positive, one was low positive, and two were negative. From the 20 hidradenomas and poromas, intermediate to high positivity was revealed in 14 cases, low positivity in three cases, and negative staining in three cases. Our study demonstrates a very high (86%) expression of TRPS1 in malignant and benign adnexal tumors that are mainly composed of islands or nodules with polygonal cells, e.g., hidradenomas. On the other hand, tumors with small ducts or strands of cells, such as MACs, appear to be completely negative. This differential staining among types of sweat gland tumors may represent either differential cells of origin or divergent differentiation and has the potential to be used as a diagnostic tool in the future.

Keywords: TRPS1; eccrine gland; sweat gland tumors.

Figure 1

Eccrine adenocarcinoma with glandular architecture (a) and high positive TRPS1 expression (b).

Figure 2

Hidradenocarcinoma with dermal tumor nodule composed of eosinophilic cells and mitoses (a) and high positive TRPS1 expression (b).

Figure 3

Porocarcinoma with back-to-back tumor nodules comprising occasional ducts and eosinophilic tumor cells (a) that stained positive for TRPS1 (b).

Figure 4

Hidradenoma with solid and cystic areas composed of eosinophilic cells and focal clear cells (a) and TRPS1 expression with accentuated staining in cells lining cystic spaces (b).

Figure 5

Poroma with proliferation of monotonous basophilic cells (a) and high positive TRPS1 expression (b).

Figure 6

Infiltrative growth pattern of MAC with cords of small cuboidal cells and occasional duct formation (a). Negative TRPS1 staining in malignant cells and dermal mesenchymal cells, with positive staining (b). Well-circumscribed syringoma with tadpole-shaped ducts (c). Lack of TRPS1 expression in neoplastic cells (d).

Figure 7

Cylindroma with islands of basaloid cells arranged in a jigsaw puzzle pattern (a). Strongest TRPS1 staining in luminal cells, weaker staining in surrounding neoplastic cells, and foci of negative staining with predilection for palisading cells (b,c).

Figure 8

More intense TRPS1 expression in the two eccrine gland sweat duct cell layers (arrow) compared to the inner cell layer of the secretory coil (arrow-head) (a). Negative TRPS1 staining in acrosyringium (b). Benign apocrine and eccrine glands (c) with negative and positive TRPS1 expression, respectively (d). TRPS1 positivity in hair follicle bulb with papillary mesenchymal body (arrow) and sebaceous gland (arrow-head) (e).