Lemma without numbering

I want to use the lemma environment without numbering because I only have one lemma. If I use the package \newtheorem{lemma}{Lemma} I get "Lemma 1" in Italics and indented:

\documentclass[journal,transmag]{IEEEtran}
\newtheorem{lemma}{Lemma}
\begin{document}
\begin{lemma}
this is my lemma
\end{lemma}
\end{document}


And if I do

\usepackage{amsthm}
\newtheorem*{lemma}{Lemma}


I get "Lemma" but in bold and plain font. I want the Italics, indentation, but without the number. What should I do?

Update

Since the class used is IEEEtran, the amsthm approach I initially suggested is not the best option (IEEEtran handles theorem-like environments in its own way). In this case, since the class doesn't make provision for unnumbered structures, you can achieve the desired unnumbered structure in a consistent way simply redefining the associated counter to \unskip:

The code:

\documentclass[journal,transmag]{IEEEtran}
\newtheorem{lemma}{Lemma}
\renewcommand\thelemma{\unskip}
\begin{document}
Test text
\begin{lemma}
this is my lemma
\end{lemma}
Test text
\end{document}


Initial version (for a standard class)

If I understood your request correctly, you can use the remark style from amsthm:

The code:

\documentclass{article}
\usepackage{amsthm}

\theoremstyle{remark}
\newtheorem*{lemma}{Lemma}

\begin{document}

\begin{lemma}
Test lemma.
\end{lemma}

\end{document}

• with this the "Lemma" is no longer indented. – Elnaz Nov 30 '14 at 1:24
• @Elnaz What do you mean by "indented"? It is never indented, by default. Please clarify. – Gonzalo Medina Nov 30 '14 at 1:25
• When I only use \newtheorem{lemma}{Lemma}, the "Lemma" keyword appears indented. But with your code above it sits exactly below the normal text above it with no indentation. – Elnaz Nov 30 '14 at 1:27
• @Elnaz No; that is not the default behaviour. Please provide a simple document, like the one in my answer illustrating the indentation you mention. – Gonzalo Medina Nov 30 '14 at 1:28
• I'll edit my original post with the code. – Elnaz Nov 30 '14 at 1:29