EUS-guided trucut biopsy of hypoechoic intramural tumors of the stomach: a single-center experience in 17 cases

Aim:

The aim of this prospective study was to assess the diagnostic yield and safety of EUS-guided trucut biopsy (TCB) in patients with hypoechoic intramural tumors (HITs) of the stomach.

Patients and Methods:

Over a period of 10.5 months 22 consecutive pts had EUS diagnosis of a gastric HIT larger than or equal to 20mm. Seventeen of them (median age 62, range 25–82) underwent EUS-TCB with a 19G Quick-Core needle (Wilson-Cook) and GF-UCT 160 scope (Olympus). The median size of the tumor was 40mm (interquartile range [IQR]: 26–50). After each needle pass the tissue obtained was assessed macroscopically and biopsy was continued until the specimen was deemed satisfactory (at least one core specimen, or smaller fragments from 2–3 needle passes). Microscopic evaluation included staining with H&E and for CD117, CD34, and SMA. Post-biopsy care involved a 2-hour in-hospital stay, a phone contact 24–48h post-procedure, and a follow-up for 30 days or until tumor removal. No antibiotic prophylaxis was given.

Results:

Technical Details: A total of 69 needle passes were done during 19 EUS-TCB procedures in 17 pts (median 4 passes / procedure; IQR: 2–5). Median procedure time was 30min. (IQR: 20–35). Fifty-three passes (77%) provided macroscopically visible tissue; the needle tray was empty in 16 cases. Specimens from 35 passes (median 2 per procedure; IQR: 1–3) were sent for histology, and 18 were stored for future genetic analysis.

Diagnostic Yield: The biopsy failed in 3 pts (18%) due to unfavorable tumor location (2 pts had GIST, one had aberrant pancreas on surgical pathology). In the remaining 14 pts (82%) EUS-TCB provided satisfactory specimens, as assessed macroscopically; however, on microscopic examination the specimens were adequate for diagnosis in only 11 cases (GIST, n=9; leiomyoma, n=1; hepatoma invading the stomach, n=1). Tumor tissue was absent in one case, and its amount was insufficient for immunostaining in 2 cases (H&E slides revealed spindle cell tumors). A repeated biopsy confirmed GIST in 2 of these pts; third patient declined second biopsy. In total, EUS-TCB established the diagnosis in 13 pts (76%), and failed in four. The EUS-TCB diagnosis was confirmed on surgical pathology in 5 pts; the remaining 8 pts are awaiting surgery or are followed.

Complications: Two pts (12%) suffered major, non-fatal septic complication: one had a streptococcal sepsis treated with iv antibiotics; another developed an abscess involving the tumor and surrounding tissues and was treated by surgical drainage.

Conclusions:

Our initial experience with EUS-TCB of gastric HITs suggests that the diagnostic yield of this method is moderately high. Antibiotic prophylaxis should be considered due to septic complications. The vast majority of HITs of the stomach are GISTs on histology.