Teaching Case

An asymptomatic 74-year-old woman with a history of ankylosing spondylitis and breast cancer underwent a thoracoabdominopelvic computed tomography (CT) for oncologic follow-up. This was her first CT scan at our institution and we did not have access to previous exams.

The thoracoabdominopelvic CT scan demonstrated a round, well-circumscribed, heterogeneous mass in the lower third of the oesophagus, isoattenuating to skeletal muscle and moderately enhancing after intravenous contrast administration. It measured 48mm in its greatest diameter and caused compression—but not obstruction—of the oesophageal lumen. There was no mediastinal lymphadenopathy or other signs of metastatic disease. The patient underwent endoscopic ultrasonography with fine needle aspiration (EUS-FNA), and the diagnosis of oesophageal gastrointestinal stromal tumours (GIST) was made. Following discussion in the oncologic multidisciplinary meeting, the patient is currently on the waiting list for surgery.

Background

Gastrointestinal stromal tumours (GISTs) account for less than 1% of gastrointestinal tumours and are mainly localised in the stomach (60%–70%) and small bowel (20%–30%) [1]. Oesophageal GISTs are exceedingly rare, corresponding to only 0.7%–5% of all GISTs [1–4]. They occur mainly in the distal third of the oesophagus (around 80% of cases), where there is a higher number of interstitial cells of Cajal, from which they originate [1–4]. Given their low incidence, specialised literature, namely radiological literature, is very scarce.

Clinical Perspective

Oesophageal GISTs are more frequently observed in younger patients compared to gastric and intestinal GISTs, with a slight male predilection [1–3]. In 50% of cases, they are asymptomatic and are incidentally diagnosed during endoscopic or radiological procedures [1]. When symptomatic, the most common manifestation is dysphagia (23%–50% of cases), followed by chest pain and gastrointestinal bleeding [1].

Imaging Perspective

The imaging features of oesophageal GISTs are similar to those of GISTs in the other most typical locations [4]. On CT, they appear as round, well-defined, bulky, frequently heterogeneous masses in the posterior mediastinum, inseparable from the oesophagus. They present a predominantly exoenteric growth pattern, without obstructing the oesophageal lumen or invading adjacent mediastinal structures [4]. They are isoattenuating to skeletal muscle and enhance moderately after intravenous contrast administration [1–4]. Internal coarse calcifications are a rare finding [4].

It is difficult to distinguish oesophageal GISTs from other submucosal tumours by imaging alone [3]. GISTs and leiomyomas appear similar on CT and endoscopic ultrasonography (EUS) [3]. On magnetic resonance imaging, diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) may be useful as an emerging modality in the differential diagnosis of oesophageal submucosal tumours [3].

EUS-FNA with pathological analysis and gene expression profiling enables definitive diagnosis and determines eligibility for adjuvant treatment with tyrosine-kinase inhibitors  [1–4].

Outcome

GISTs have malignant potential, and surgery without dissection of clinically negative lymph nodes is the mainstay of treatment [1]. Surgical tumour enucleation should be considered for low to intermediate malignancy risk GISTs, while esophagectomy is indicated in the remaining cases [1–4]. Neoadjuvant and/or adjuvant therapy with tyrosine-kinase inhibitors may play a role in the treatment of these tumours [1–3].

Take Home Message / Teaching Points

Oesophageal GISTs are rare, with limited evidence on their imaging features and management options. Nonetheless, they must be taken into account in the differential diagnosis of an intramural oesophageal mass. Endoscopic ultrasonography with fine needle aspiration (EUS-FNA) enables definitive diagnosis. Surgery with or without tyrosine-kinase inhibitors therapy is the current mainstay of treatment.

All patient data have been completely anonymised throughout the entire manuscript and related files.