Three cases to date, 3 female patients aged 24, 63, and 85 years (Möller et al., 2008).

There was one atypical, one poroid, and one solid hidradenoma.

Prognosis is good in this benign disease.

The t(6;22)(p21;q12) was the sole anomaly in the only case with karyotypic studies; the 2 other cases were detected by the presence of the fusion transcript.

POU5F1 (POU class 5 homeobox 1)

6p21.33

Homeobox protein (homeodomain in amino acids 230-289 in the 360 aa isoform) with a POU domain (in aa 138-212). Binds the sequence 5-ATTTGCAT-3. Transcription factor.

EWSR1 (Ewing sarcoma breakpoint region 1)

22q12.2

From N-term to C-term: a transactivation domain (TAD) containing multiple degenerate hexapeptide repeats, 3 arginine/glycine rich domains (RGG regions), a RNA recognition motif, and a RanBP2 type Zinc finger. Role in transcriptional regulation for specific genes and in mRNA splicing.

5 EWSR1 - 3 POU5F1. EWSR1 exon 6 is fused in frame to POU5F1 exon 2.

Fusion of the N terminal transactivation domain of EWSR1 to the POU and the homeobox (DNA binding domain) of POU5F1.