The clinical presentation of multiple, rare, skin appendage tumours called cylindromas has been attributed to germline mutations in the tumour suppressor gene CYLD (OMIM 605018). Brooke-Spiegler Syndrome (BSS), familial cylindromatosis (FC) and multiple familial trichoepitheliomas (MFT) (OMIM #605041, #132700, #601606 respectively) differ due to the types of other skin appendage tumour seen together with cylindroma, such as spiradenoma and trichoepithelioma. Previously thought to be separate entities, they are now viewed as allelic variants with overlapping phenotypes, supported by mutation analysis of CYLD . The conditions display autosomal dominant inheritance and affected individuals develop multiple benign skin tumours most commonly on the head and neck.

CYLD testing can be performed using PCR and Sanger sequencing for patients with:
1. Multiple cylindromas, spiradenomas or trichoepitheliomas.
2. A single cylindroma, spiradenoma or trichoepithelioma and an affected first-degree relative with any of these tumours.
3. An asymptomatic family member at 50% risk with a known mutation in the family.