Assessment of the clinical usefulness of ultrasound-guided cytological specimens obtained from gastrointestinal lesions in dogs and cats

Diagnostic yield of percutaneous, ultrasound-guided, fine needle aspirates of the gastrointestinal wall: a retrospective analysis of 152 samples

OBJECTIVES

The aim was to assess the technical success of percutaneous ultrasound-guided fine needle aspirates of gastrointestinal wall lesions and evaluate predictors of success. Secondary aims included comparing the cytological diagnosis with histopathology, evaluating the utility of concurrent locoregional lymph node cytology and assessing the procedure's complication rate.

MATERIAL AND METHODS

Gastrointestinal wall cytology from 75 dogs and 70 cats obtained between 2018 and 2023 were reviewed and categorised as successful (resulting in a diagnostic cytology report) and accurate (resulting in the correct diagnosis when compared to histopathology). Unsuccessful fine needle aspirates, not submitted for cytology, were not recorded. Variables recorded included animal signalment, lesion and lymph node's appearance on ultrasound, size, location, number of smears submitted and experience of the ultrasonographer.

RESULTS

One hundred and fifty-two reports were analysed. Eighty-eight (58%) were successful: three normal epithelium, 21 inflammatory processes and 64 neoplasms. Variables associated with increased technical success included description of a mass, higher number of slides submitted and thickness of gastrointestinal lesion on ultrasound. Comparison with histopathology, performed for 17 lesions, showed discrepancies in eight, complete agreement in seven and partial in two. Eighty-four loco-regional lymph nodes were sampled, of which, 67 were successful (80%) and 52 brought additional clinical information (supporting GI wall cytology or diagnosing neoplasia not identified on GI wall cytology). No complication strictly attributable to gastrointestinal wall sampling was reported but when possibly related, death of the patient occurred in 2.5% of cases.

CLINICAL SIGNIFICANCE

Ultrasound-guided fine needle aspirate of gastrointestinal wall had moderate accuracy and was unsuccessful in 42% of cases, but technical success increased when sampling mass lesions, thicker intestinal layers and submitting more slides.

Association of serum and fecal microRNA profiles in cats with gastrointestinal cancer and chronic inflammatory enteropathy

BACKGROUND

Differentiation of gastrointestinal cancer (GIC) from chronic inflammatory enteropathies (CIE) in cats can be challenging and often requires extensive diagnostic testing. MicroRNAs (miRNAs) have promise as non-invasive biomarkers in serum and feces for diagnosis of GIC.

HYPOTHESIS/OBJECTIVES

Cats with GIC will have serum and fecal miRNA profiles that differ significantly from healthy cats and cats with CIE. Identify serum and fecal miRNAs with diagnostic potential for differentiation between cats with GIC and CIE as compared to healthy cats.

ANIMALS

Ten healthy cats, 9 cats with CIE, and 10 cats with GIC; all client-owned.

METHODS

Cats were recruited for an international multicenter observational prospective case-control study. Serum and feces were screened using small RNA sequencing for miRNAs that differed in abundance between cats with GIC and CIE, and healthy cats. Diagnostic biomarker potential of relevant miRNAs from small RNA sequencing and the literature was confirmed using reverse transcription quantitative real-time PCR (RT-qPCR).

RESULTS

Serum miR-223-3p was found to distinguish between cats with GIC and CIE with an area under the curve (AUC) of 0.9 (95% confidence interval [CI], 0.760-1.0), sensitivity of 90% (95% CI, 59.6-99.5%), and specificity of 77.8% (95% CI, 45.3-96.1%). Serum miR-223-3p likewise showed promise in differentiating a subgroup of cats with small cell lymphoma (SCL) from those with CIE. No fecal miRNAs could distinguish between cats with GIC and CIE.

CONCLUSION AND CLINICAL IMPORTANCE

Serum miR-223-3p potentially may serve as a noninvasive diagnostic biomarker of GIC in cats, in addition to providing a much needed tool for the differentiation of CIE and SCL.

Association of fecal and serum microRNA profiles with gastrointestinal cancer and chronic inflammatory enteropathy in dogs

BACKGROUND

Reliable biomarkers to differentiate gastrointestinal cancer (GIC) from chronic inflammatory enteropathy (CIE) in dogs are needed. Fecal and serum microRNAs (miRNAs) have been proposed as diagnostic and prognostic markers of GI disease in humans and dogs.

HYPOTHESIS/OBJECTIVES

Dogs with GIC have fecal and serum miRNA profiles that differ from those of dogs with CIE.

AIMS

(a) identify miRNAs that differentiate GIC from CIE, (b) use high-throughput reverse transcription quantitative real-time PCR (RT-qPCR) to establish fecal and serum miRNA panels to distinguish GIC from CIE in dogs.

ANIMALS

Twenty-four dogs with GIC, 10 dogs with CIE, and 10 healthy dogs, all client-owned.

METHODS

An international multicenter observational prospective case-control study. Small RNA sequencing was used to identify fecal and serum miRNAs, and RT-qPCR was used to establish fecal and serum miRNA panels with the potential to distinguish GIC from CIE.

RESULTS

The best diagnostic performance for distinguishing GIC from CIE was fecal miR-451 (AUC: 0.955, sensitivity: 86.4%, specificity: 100%), miR-223 (AUC: 0.918, sensitivity: 90.9%, specificity: 80%), and miR-27a (AUC: 0.868, sensitivity: 81.8%, specificity: 90%) and serum miR-20b (AUC: 0.905, sensitivity: 90.5%, specificity: 90%), miR-148a-3p (AUC: 0.924, sensitivity: 85.7%, specificity: 90%), and miR-652 (AUC: 0.943, sensitivity: 90.5%, specificity: 90%). Slightly improved diagnostic performance was achieved when combining fecal miR-451 and miR-223 (AUC: 0.973, sensitivity: 95.5%, specificity: 90%).

CONCLUSIONS AND CLINICAL IMPORTANCE

When used as part of a diagnostic RT-qPCR panel, the abovementioned miRNAs have the potential to function as noninvasive biomarkers for the differentiation of GIC and CIE in dogs.

Needle rinse cell blocks as an ancillary technique: Diagnostic and clinical utility in gastrointestinal neoplasia

BACKGROUND

Fine-needle aspirate (FNA) cytology is often the first-choice method for diagnosing gastrointestinal nodular lesions. The FNA material can be converted to histopathology specimens by a needle rinse cell block (NRCB) technique, allowing ancillary studies to refine the cytologic diagnosis. Despite use in human pathology, NRCB has never been applied to canine or feline gastrointestinal neoplasia.

OBJECTIVE

This study described NRCB methodology and its diagnostic utility in specific cases of neoplastic gastrointestinal lesions.

METHODS

Needle rinses with saline were performed after ultrasound-guided FNAs of two intestinal lymphomas (canine and feline) and a canine gastrointestinal stromal tumor (GIST). The NRCB was prepared using the cell tube block technique and processed for paraffin embedding. Routine immunohistochemistry protocols (using CD3, PAX-5, and Ki-67 for lymphoma cases and vimentin, desmin, S-100, and KIT markers for GIST) were applied to NRCB sections, and the results were compared with matched tissue biopsies.

RESULTS

NRCBs with adequate cell numbers, preservation, and good separation of blood were obtained. The diagnosis and immunophenotyping were confirmed in both cases of lymphoma in NRCBs. In the GIST, the immunolabeling of the neoplastic cells in NRCB was completely concordant with the tissue biopsy.

CONCLUSIONS

The described methodology is suitable for veterinary settings, having few technical requirements and low invasiveness. The presented cases of gastrointestinal neoplasia highlight the utility of NRCBs as a platform to conduct ancillary studies and refine the cytologic diagnosis.