Gastrointestinal schwannoma

Gastrointestinal schwannomas are extremely rare mesenchymal neoplasms which arise in relation to the gastrointestinal tract.

Epidemiology

They are reported to typically present at about the 3^rd to 5^th decades of life ⁴.

Clinical presentation

Patients are often asymptomatic but may occasionally present with abdominal discomfort or upper gastrointestinal bleeding from overlying mucosal ulceration.

Pathology

Although they arise from Schwann cells of the gastrointestinal wall neural plexa ⁴, they are considered to be distinctively different from the conventional schwannomas that arise in soft tissue or the central nervous system in terms of histological features.

Location

• stomach: 60-70% of cases (commonest location)
• colon: next commonest location
• rectum

Markers

S100 protein is strongly positive ^1,6.

Radiographic features

CT

• typically seen as a well-defined, rounded, mural mass(es) with homogeneous attenuation ²
• tends to lack cystic change and haemorrhage

MRI

Reported features include ⁴:

• T1:low or intermediate signal
• T1 C+ (Gd):may demonstrate slow but relative uniform enhancement
• T2:high signal

Treatment and prognosis

They are benign tumours and carries a much better prognosis compared with gastrointestinal stromal tumours.

History and etymology

Initially reported by Daimaru et al. in 1988 ¹

Differential diagnoses

• gastrointestinal stromal tumour (GIST)
• gastrointestinal leiomyoma
• gastrointestinal tract neurofibroma