Lower Extremity Overgrowth Associated with a Somatic MTOR Variant.

There are many causes of lower extremity overgrowth. We present a 69-year-old female who was referred to the Boston Lymphatic Center due to left lower extremity enlargement. Her history and physical examination were inconsistent with lymphedema and a lymphoscintigram excluded this condition. She was hypothesized to have a condition on the PIK3CA-related overgrowth spectrum. The overgrown tissue was resected and to obtain a diagnosis, it was subjected to targeted next-generation sequencing, which showed an MTOR (NM_001386500:c.6644C>T (p.Ser2215Phe)) variant. This mutation has not been previously associated with lower extremity overgrowth.