Endoscopic findings do not predict per-oral pyloromyotomy (POP) response

INTRODUCTION

Gastroparesis is a life-altering diagnosis caused by the stomach's inability to function in the absence of a mechanical obstruction. The primary causes are idiopathic, diabetic, and postoperative. Our first-line treatment for medical refractory gastroparesis is the endoscopic per-oral pyloromyotomy (POP) procedure. Predicting clinical response cost effectively remains elusive.

METHODS

All patients who underwent a POP procedure at our institution by a single surgical endoscopist from January 1, 2019 to June 30, 2020 were retrospectively reviewed. All endoscopic data were prospectively collected. The patients were followed by a survey including the Gastroparesis Cardinal Symptom Index (GCSI) and other relevant postoperative measures. The primary endpoint was clinical response defined as ≥ 1.0 decrease in the GCSI from preoperative to the time of survey. Secondary outcome was normalization of the gastric emptying study (GES).

RESULTS

Our patient population is 85% female and has an average age of 44.8 years. The diagnosis of gastroparesis is 71% iatrogenic, 19% postoperative, and 10% diabetic. On endoscopy, 30% had bile in the stomach and 65% had any degree of pylorospasm. The primary outcome measure of clinical response was 39% at an average of 697 ± 151 days post-POP, but 66% of patients attested to an improvement in their symptoms. Of 68 postoperative gastric emptying studies 50% normalized at an average of 145 ± 98 days. Following univariate and multivariate analyses of preoperative data and endoscopic findings, there were no significant predictors of clinical response. A preoperative GCSI ≥ 2.6 trends toward significance (OR 6.87, p = 0.058).

CONCLUSION

Endoscopic findings at the time of POP do not correlate with clinical response. The GCSI model currently used to measure clinical response may not accurately capture the full clinical picture. The long-term durability of endoscopic myotomy to treat medical refractory gastroparesis needs to be studied further to improve patient selection.

Gastric Mass: Intramural Hematoma

Gastric masses can be challenging to diagnose pre-operatively due to their heterogeneity in presentation and work-up. One must be cautious that a seemingly benign mass may be malignant and vice versa. Some of the more common gastric masses include peptic ulcer, adenocarcinoma, and gastrointestinal stromal tumour. These diagnoses have vastly different management strategies despite similar presentations. The case presented here is an example of this management, highlighting a patient with a gastric bleeding mass initially thought to be a gastrointestinal stromal tumour. However, on final pathology, the mass was determined to be benign, an ulcerated hematoma.

Histopathology of N-methyl-N-nitrosourea-induced mesenchymal tumours of the rat urinary bladder

The present study reports the induction, histopathology, immunocytochemistry, growth pattern and proliferative behaviour of mesenchymal tumours of the urinary bladder of rats induced by a single intravesical dose (5 mg/kg/body weight) of N-methyl-N-nitrosourea (MNU). In 14 of 283 female Wistar rats (incidence: 4.9%). 16 non-epithelial tumours had developed after an experimental period of 14 months. The most common histological type induced was of fibrohistiocytic origin (eight benign-appearing and three malignant fibrous histiocytomas). Furthermore, two pure histiocytomas (one benign and one malignant) and three capillary and cavernous haemangiomas were produced. Since no metastases occurred and no clear-cut distinction between a merely expansive and a truly invasive growth was possible, the diagnosis of malignancy was based on the degree of cellular atypia and the mitotic activity. The benign-appearing fibrous histiocytomas showed a mean mitotic index of 0.06% and the malignant fibrous histiocytomas of 0.34%. The mitotic activity of the malignant histiocytoma was threefold (0.78%) as high as in the benign-appearing histiocytoma (0.25%). There exist close morphological similarities between the induced mesenchymal tumours in the rat and those occurring in the human bladder. Although the spectrum of histological types of mesenchymal tumours seen in the rat bladder was narrower than that encountered in man, MNU seems suitable for further studying the histogenesis, histopathology and biology of experimentally induced non-epithelial bladder neoplasms to gain information for a better understanding of the pathogenesis of human disease.