Peritoneal adenocarcinoma diagnosed by endoscopic ultrasound-guided through-the-needle biopsy

The diagnosis of peritoneal carcinomatosis accompanied by ascites is challenging, particularly when the primary site remains unidentified. While cytological examination of ascites is commonly advocated, the diagnostic sensitivity is approximately 60% [1]. The remaining 40% of patients may require more invasive procedures, such as laparoscopy or laparotomy. In recent years, endoscopic ultrasound (EUS) has extended its reach to peritoneal carcinomatosis, offering enhanced visualization and a minimally invasive approach [2] [3]. In the case presented here, we utilized an innovative technique, EUS-guided through-the-needle (EUS-TTN) biopsy, to facilitate the pathological diagnosis of peritoneal carcinomatosis.

A 77-year-old woman was referred to our hospital for abdominal distension. Computed tomography demonstrated abnormal peritoneal thickening alongside significant ascites accumulation without detecting any space-occupying lesion ([Fig. 1]). Subsequent exfoliative cytology of ascites had negative findings. The patient’s poor condition precluded diagnostic laparoscopy. Consequently, we decided to conduct EUS-TTN biopsy for pathological diagnosis. Under EUS guidance, the peritoneum was visualized as a frond-like hyperechoic structure with diffuse thickening contrasted against the anechoic background of the ascites. Utilizing a 19-G fine-needle aspiration (FNA) needle via a transrectal route, the thickened peritoneum was punctured. After the needle tip was positioned into the rectouterine pouch, the stylet was removed and a micro-forceps (disposable micro-forceps; UShare Medical, China) was introduced through the needle to collect peritoneal tissue samples from the rectouterine pouch ([Video 1]). Three biopsies were taken using the micro-forceps, without adverse events ([Fig. 2]). Immunohistochemistry identified malignant adenocarcinoma ([Fig. 3]). The patient underwent chemotherapy with the outcome being a favorable recovery.

Fig. 1 Computed tomography (CT) images; no space-occupying lesions were detected. a Diffuse, irregular, sheet-like peritoneal (arrowheads, axial plane). b, c Peritoneal thickening in the rectouterine pouch (arrowheads, sagittal and axial planes).

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Endoscopic ultrasound-guided through-the-needle biopsy of peritoneal adenocarcinoma.Video 1

Fig. 2 Micro-forceps held by the operator, showing biopsy samples.

Fig. 3 Histopathology of the peritoneal tissue samples. a Hematoxylin and eosin staining showed atypical tumor cells (magnification ×200). b–e Immunohistochemical staining was positive for AE1/3, EMA, CEA, Ki-67(magnification × 200), respectively.

EUS-TTN biopsy offers a valuable alternative for peritoneal tissue acquisition, especially for patients who are unable to tolerate surgical interventions. The transrectal route is preferred as it allows direct access to peritoneal areas where sedimentation and metastasis are most likely to occur under the influence of gravity.

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Conflict of Interest

The authors declare that they have no conflict of interest.

• References

• 1 Karoo RO, Lloyd TD, Garcea G. et al. How valuable is ascitic cytology in the detection and management of malignancy?. Postgrad Med J 2003; 79: 292-294
• 2 Rana SS, Bhasin DK, Srinivasan R. et al. Endoscopic ultrasound-guided fine needle aspiration of peritoneal nodules in patients with ascites of unknown cause. Endoscopy 2011; 43: 1010-1013
• 3 Peter S, Eltoum I, Eloubeidi MA. EUS-guided FNA of peritoneal carcinomatosis in patients with unknown primary malignancy. Gastrointest Endosc 2009; 70: 1266-1270

Publication History

Article published online:
05 June 2024