Perianal Disease and Granulomas: Think Out of the Box…

Chronic granulomatous disease (CGD) is a primary immunodeficiency due to a malfunction of NADPH oxidase. It is characterized by recurrent and severe infections caused by catalase-positive microorganisms and autoinflammatory manifestations. Recently, there has been described an NCF4 gene variant that causes a deficiency of p40, a subunit of NADPH oxidase. Patients with this deficiency appear to have a less severe clinical form as compared to classic CGD.

A 15-year-old girl with vulvar lichen planus since she was 2 years old and suspected Crohn's disease (CD) was first seen at our hospital. At the age of 12 years, she had been submitted to sacrococcygeal cyst exeresis, without cicatrization of the surgical wound and extension of the lesion to the perianal area. The diagnosis of CD was questioned, and the patient underwent an endoscopic and radiologic assessment, which was normal. A skin biopsy from the perianal area revealed a granuloma; thus, CD with isolated perianal disease was assumed. After several different treatments including antibiotics, infliximab, and adalimumab, the perianal lesion persisted, with no associated gastrointestinal symptoms. Therefore, the hypothesis of an immunodeficiency was considered. An immunologic and genetic study revealed reduced oxidative burst in the phorbol myristate acetate test, with diminished reactive oxygen species production and a homozygous mutation in the NCF4 gene. The adolescent started prophylactic trimethoprim-sulfamethoxazole and became asymptomatic.

The present case highlights that alternative diagnoses to CD must be considered in the presence of isolated perianal disease with granulomatous inflammation, especially when the disease is refractory to conventional CD therapy.