Granular cell tumour in a patient with Crohn's disease treated with infliximab: coincidence or causal relationship?

Granular cell tumour (or Abrikossoff's tumour) was first described by Abrikossoff in 1926. This is a rare benign neoplasm of unclear histogenesis that is generally believed to be of nerve sheath origin. Usually, it presents as a solitary lesion, located mainly in the subcutaneous tissue of the head, or the neck, or in the oral cavity, such as a tongue lesion, although it may develop anywhere in the body. Approximately 1-2% of granular cell tumours are malignant. Granular cell tumours are extremely rare in patients with inflammatory bowel disease. To the best of our knowledge, granular cell tumours have never been reported in association either with Crohn's disease or scheduled infliximab treatment. Herein, we report a case of a granular cell tumour that presented as a subcutaneous skin nodule of the right lumbar area without any associated local or systemic symptoms in a 41-year-old woman with Crohn's disease who was receiving scheduled treatment with infliximab (5 mg/kg every 8 weeks) for 7 years.