Eccrine Porocarcinoma with Bowenoid Changes: Epithelial Membrane Antigen is Not a Useful Marker for Malignant Tumours Arising from Eccrine Gland Structures

Abstract

A case of eccrine porocarcinoma with Bowenoid changes is reported. We compared the results of immunohistochemical staining for epithelial membrane antigen in the present case with results in Bowen's disease to determine whether the presence of epithelial membrane antigen (EMA) enabled us to differentiate between Bowen's disease and eccrine porocarcinoma with Bowenoid changes. Histologically, the present tumour was characterized by atypical clear cells with Bowenoid changes as well as uniform small cells and intradermal nests with ductal structures. The membrane and cytoplasm of uniform small cells and ductal luminal surfaces were positive for EMA. However, the atypical cells with Bowenoid changes were negative for this. In contrast, tumour cells in Bowen's disease were positive for EMA. Although EMA is known to be a useful marker for some benign tumours derived from eccrine ducts, we found it difficult to distinguish eccrine porocarcinoma with Bowenoid changes from Bowen's disease using immunohistochemical staining for EMA.

Eccrine porocarcinoma and Bowen's disease arising in a seborrhoeic keratosis

“…2f). Eccrine porocarcinoma is characterized by epidermotropism and pagetoid diffusion in the epidermis, and may show bowenoid changes 4 . However, in this patient, the BD and eccrine porocarcinoma lesions were separated completely by the SK lesion with sufficient distance to allow each lesion to be clearly identified.…”

Distinct regulations driving YAP1 expression loss in poroma, porocarcinoma and RB1‐deficient skin carcinoma

“…3,5 Although immunohistochemical detection of carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) to highlight the ductal structures support the diagnosis of porocarcinoma, their diagnostic performance has not been evaluated for molecularly confirmed cases. 3,6 In 2019, Sekine et al reported in eccrine poroma and porocarcinoma the detection of recurrent rearrangements of YAP1, a gene encoding for a downstream effector of the Hippo pathway, either with MAML2 or NUTM1. 7 Furthermore, the authors demonstrated that fusion of YAP1 resulted in the loss of expression of the C-terminal part of the YAP1 protein (C-ter YAP1), a phenomenon that can be detected by immunohistochemistry.…”

“…The distinction between porocarcinoma and poorly differentiated squamous cell carcinoma (SCC) on morphological and immunohistochemical grounds can be challenging in current practice and based on reported criteria 3,5 . Although immunohistochemical detection of carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) to highlight the ductal structures support the diagnosis of porocarcinoma, their diagnostic performance has not been evaluated for molecularly confirmed cases 3,6 …”