Metastatic squamous cell carcinoma arising from a retrorectal cystic hamartoma (tailgut cyst)

Abstract

We report a case of a metastatic squamous cell carcinoma arising from a retrorectal cystic hamartoma (RCH). The RCH was first diagnosed at Singapore General Hospital (SGH) on magnetic resonance imaging (MRI) scan, and subsequently underwent malignant transformation and metastasized years later. Malignant transformation of RCHs is an exceedingly rare event and usually manifests as an adenocarcinoma or a well differentiated neuroendocrine tumour. There have only been two previously reported cases of squamous cell carcinoma and neither of them lead to metastatic disease. This is the first reported case of a metastatic tumour arising from a RCH.

Keywords

• Retrorectal
• Tailgut
• Hamartoma
• RCH
• Cyst
• Cystic