Coffin-Siris Syndrome and SMARCB1 Mutation Presenting With Schwannomatosis: A Case Report and Literature Review.

Coffin-Siris syndrome (CSS) is a rare genetic condition associated with mutations in genes responsible for the modulation of gene expression and chromatin remodeling. Patients with CSS commonly present with congenital anomalies, intellectual disabilities, and developmental delays. We describe a case of a 28-year-old woman with a confirmed diagnosis of CSS and mutation who presents with multiple schwannomas and an intra-abdominal neurofibroma. The patient underwent embolization and resection of an enlarging, symptomatic schwannoma of her left medial upper arm. In detailing the patient's presentation, this case report underscores the association between mutations, CSS, and tumorigenesis.