Fine needle aspiration, often abbreviated FNA, is one of the most powerful yet underappreciated tools in veterinary medicine. The technique involves inserting a thin needle into a mass and drawing out cells, which are then smeared onto a slide, stained, and examined under a microscope. Compared with surgical biopsy, it is minimally invasive, carries low risk, costs far less, and can produce results within minutes to days. When a dog or cat presents with a persistent lump measuring at least one centimeter, roughly the size of a pea, that has been present for a month or longer, established guidelines from the American Animal Hospital Association recommend FNA or biopsy to obtain a diagnosis before any treatment decisions are made. The rationale is straightforward: knowing whether a mass is benign or malignant, and what type of tumor it might be, fundamentally changes how a veterinarian plans surgery, staging, and follow-up care.

The stakes are considerable. Roughly 30 percent of all tumors in dogs and cats arise in the skin or the tissue just beneath it, and malignancy rates in these lesions vary dramatically between species. In dogs, an estimated 20 to 40 percent of skin tumors are malignant; in cats, the figure climbs to between 70 and 82 percent. Because a lump that feels benign to the examining hand may in fact be an aggressive cancer, the guidelines emphasize that no definitive diagnosis can ever be made on palpation alone. Yet the new survey suggests that in everyday practice, clinical impression frequently wins out over cytology.

The research team, led by Gillian Dank of Onco Pet Veterinary Services in Israel along with colleagues at HT Vet and in private consulting, distributed a 16-question survey by email to 10,000 small-animal veterinary professionals across the United States, including veterinarians, veterinary technicians, and practice managers. A total of 240 respondents completed the questionnaire, a response rate of 2.4 percent, with 235 providing fully answered forms. Most respondents were veterinarians, about 62 percent of practices were independently owned, and the vast majority worked in general practice. The survey asked about daily caseloads of mass patients, the proportion of cases in which FNA was performed, whether samples were evaluated in-house or sent to reference laboratories, the perceived rate of inconclusive results, and the barriers that discouraged the test.

The statistical analysis, conducted in Python using standard tests of association, revealed several striking patterns. Clinicians who evaluated four or more patients with dermal or subcutaneous masses per day were significantly less likely to perform FNA than those seeing fewer than four such patients daily, a difference that reached statistical significance. The mean FNA rate fell from roughly 41 to 42 percent among lower-volume respondents to 33 percent among those with the heaviest caseloads. The authors suggest that the cumulative cognitive load of making dozens of clinical decisions each day may push busy veterinarians toward a quick wait-and-see discharge rather than an additional procedure, particularly when a lump is an incidental finding during a visit for something else.

Experience, surprisingly, worked in the opposite direction. Clinicians with more than 20 years in practice were significantly over-represented among the high users of FNA, performing the test on more than half of masses at rates of 40 to 44 percent, compared with only 19 to 24 percent among less experienced colleagues. This contradicts the intuitive assumption that seasoned veterinarians feel comfortable judging a lump by look and feel alone. The authors speculate that decades of practice bring greater familiarity with the aspiration technique and a deeper appreciation of its clinical utility, gained through years of watching palpation-based guesses go wrong.

The barriers veterinarians cited for skipping the test were revealing. The most common primary reason, selected by 35 percent of respondents, was the perception that the mass was benign and did not require further investigation. Cost concerns came second at 32 percent, and client declination for reasons other than cost accounted for 19 percent. Taken together, the cost and refusal categories suggest that in roughly half of cases, the veterinarian would have performed the aspiration if the owner had agreed. Only 8 percent cited limited confidence in the diagnostic value of FNA itself, and just 4 percent pointed to the time the procedure takes. Notably, when the same respondents were asked what percentage of lumps could be accurately diagnosed from palpation and history alone, half estimated that this was reliable in fewer than 10 percent of cases, a striking contradiction with their stated reliance on clinical impression. The authors interpret this as a gap between theoretical knowledge and the practical, split-second decision-making of a busy appointment.

One of the most consequential findings concerned surgery. Respondents reported performing excisional biopsies, in which the entire mass is surgically removed, without any prior FNA in an average of 30 percent of cases. Clinicians who expressed confidence in diagnosing lumps by palpation alone were two and a half times more likely to skip the preoperative aspiration. This matters because knowing the tumor type before surgery provides critical information about local invasiveness, metastatic potential, and whether the cancer spreads through lymphatic or blood vessels, all of which influence the width of surgical margins, the need for preoperative staging tests, and the overall surgical strategy. Since the first operation often offers the best chance of complete tumor removal, proceeding blind may, in some cases, compromise the outcome. The authors caution, however, that there are legitimate reasons to excise directly, such as very small masses that appear benign, or palliative procedures where tumor typing would not change the plan.

The survey also examined the role of digital cytology, a rapidly growing technology that allows slide images to be transmitted to remote board-certified clinical pathologists for interpretation. About 35 percent of clinics reported using such services, with medium and large practices significantly more likely to adopt them than small ones. Counterintuitively, clinics with digital cytology performed fewer aspirations overall, 35 percent versus 42 percent, evaluated fewer samples in-house, and reported higher rates of inconclusive results. The authors offer several possible explanations: clinicians may expect definitive answers from submitted samples and grow frustrated when findings are non-diagnostic; the higher cost of digital services may discourage routine use; slide preparation and upload take time during busy consultations; or the association may simply be confounded by the fact that larger, high-volume clinics, which already perform fewer aspirations, are also the ones most likely to have the technology.

The study has limitations that the authors acknowledge candidly. The response rate was low, the survey reached only US-based subscribers of a single professional publication, and many answers relied on recollection rather than verified clinical records. The questionnaire also did not capture the clinical reasoning behind every decision to skip aspiration. Even so, the overall picture is consistent: a fast, cheap, minimally invasive test that veterinary schools teach and guidelines endorse is being underused, especially where caseload pressure is highest. The authors argue that better integration of FNA into routine workflows, along with hands-on training for veterinary students and practicing clinicians in both aspiration technique and slide assessment, could close the gap between what the guidelines recommend and what actually happens when a worried owner points to a lump on their pet. Early diagnosis, they emphasize, remains one of the most powerful predictors of a good outcome in veterinary oncology, and the pea-sized lump dismissed today may be the aggressive tumor that a two-minute needle test could have caught in time.

Subject of Research: Underuse of fine needle aspiration for diagnosing skin masses in dogs and cats in veterinary practice

Article Title: Underutilization of fine needle aspiration for canine and feline superficial masses-survey results

Article References: Dank, G., Buber, T., Levy-Hirsch, L., Fink, A., Marks, N., Greenberg, U., & Hanael, E. (2026). Underutilization of fine needle aspiration for canine and feline superficial masses-survey results. Veterinary Oncology, 3(1), Article 25. https://doi.org/10.1186/s44356-026-00077-0

Image Credits: AI Generated

DOI: 10.1186/s44356-026-00077-0

Keywords: fine needle aspiration, veterinary oncology, cytology, dogs, cats, skin masses, biopsy, digital cytology, diagnostic guidelines, survey research, cancer diagnosis, veterinary practice

The patient at the center of the report was a 64-year-old woman with a history of diabetes mellitus, hypertension, and chronic kidney disease. She had no complaints whatsoever, no palpable thyroid nodule, no swollen lymph nodes, and no family history of thyroid cancer or other endocrine tumors. Her medullary thyroid carcinoma came to light only because an unrelated metabolic work-up revealed an isolated elevation of procalcitonin, a biomarker more commonly associated with severe bacterial infections. That incidental finding set in motion a diagnostic chain that ultimately uncovered a two-centimeter tumor in her left thyroid lobe, along with a second, entirely separate and unexpected cancer measuring just half a millimeter in the right lobe.

The diagnostic challenge in this case was considerable, and it illustrates why medullary thyroid carcinoma remains one of the most treacherous diagnoses in endocrinology. Roughly one quarter of cases arise in the setting of inherited syndromes such as multiple endocrine neoplasia type 2A and 2B or familial medullary thyroid carcinoma, all driven by germline mutations in the RET proto-oncogene. The majority of cases, however, are sporadic, and somatic RET mutations are found in about sixty percent of these tumors. The specific mutation involved matters enormously: the common p.Met918Thr alteration produces a markedly more aggressive course, while RET-negative tumors often carry RAS-family mutations instead. Because family history can be absent in up to half of hereditary cases, guidelines recommend germline RET screening even in patients who appear to have sporadic disease. In this particular patient, germline testing could not be performed, leaving an open question about whether an occult hereditary syndrome might have been at play.

Laboratory evaluation told an intriguing story. The woman’s serum calcitonin—the classic hallmark of C-cell derived tumors—measured 2100 nanograms per liter, and her carcinoembryonic antigen, or CEA, a glycoprotein used as a tumor marker, stood at 20.8 nanograms per milliliter. Yet neither of these values had triggered the initial investigation. Instead, it was procalcitonin that raised the alarm, and the report’s authors emphasize that this was no accident. Procalcitonin secretion is a recognized physiological product of thyroid parafollicular C cells, so once a C-cell neoplasm is present, its elevation is expected rather than surprising. In this patient, the procalcitonin signal happened to arrive first, in a clinical context—chronic kidney disease—where such an elevation could easily have been dismissed or misattributed.

The authors argue that the concurrent CEA elevation was actually the more diagnostically instructive finding. CEA is not specific to C cells, and an unexplained CEA rise in an older adult is conventionally pursued as a possible sign of gastrointestinal malignancy. Several previous reports have described medullary thyroid carcinoma presenting initially as an isolated CEA elevation that was ultimately traced back to the thyroid. In one directly comparable case, a patient with subclinical hyperthyroidism was found to have sporadic medullary thyroid carcinoma first suspected because of a high CEA level, with strong CEA immunoreactivity later confirmed on the surgical specimen. Larger retrospective series have also shown that preoperative CEA correlates with tumor size and stage, with concentrations above roughly 270 to 400 nanograms per milliliter associated with larger or metastatic disease. The modest CEA elevation in this new case fits neatly with the small, low-grade, node-negative tumor that pathology ultimately revealed.

Chronic kidney disease complicated the interpretation at every turn. Reduced renal clearance can independently cause mild elevations of both calcitonin and CEA, which means that in a patient like this, both markers could have been dismissed as artifacts of her kidney function. The report’s authors stress that calcitonin elevation in chronic kidney disease should never be reflexively attributed to impaired renal clearance alone, because excluding an underlying C-cell malignancy remains essential. Their message is a warning against a common diagnostic shortcut: in patients with kidney disease, an elevated calcitonin level demands the same rigorous work-up it would receive in anyone else, including neck imaging, fine-needle aspiration with calcitonin measurement in the washout fluid, and appropriate immunocytochemistry.

That work-up, in this case, was thorough. Neck ultrasonography showed solid hypoechoic nodules in both lobes. Fine-needle aspiration of the left lobe nodule was consistent with medullary thyroid carcinoma, with calcitonin detected in the needle washout and immunocytochemistry showing positivity for chromogranin A and CEA alongside negativity for thyroglobulin—the protein made by ordinary thyroid cells, whose absence helps distinguish medullary from other thyroid cancers. Computed tomography of the neck, thorax, and abdomen found no distant metastases, and a gallium-68 DOTATATE PET/CT scan, which images somatostatin receptor expression, showed uptake in the thyroid nodule and several cervical and axillary lymph nodes. The patient underwent total thyroidectomy with bilateral central neck dissection, and the surgery went without complication.

Pathology confirmed a two-centimeter, partially encapsulated, low-grade medullary thyroid carcinoma with negative surgical margins, no vascular or perineural invasion, and a Ki-67 proliferation index of just one percent. All seventeen dissected lymph nodes were free of metastasis. Tumor cells stained positive for calcitonin, CEA, chromogranin A, synaptophysin, and several other markers, with loss of CD56 expression. Interestingly, amyloid deposition—a classic pathological feature of medullary thyroid carcinoma—could not be demonstrated. And in a remarkable twist, an incidental 0.05-centimeter classic papillary microcarcinoma, an entirely different type of thyroid cancer, was found in the right lobe. After surgery, the patient’s biomarkers collapsed dramatically: calcitonin fell from 2100 to 3.1 nanograms per liter and CEA from 20.8 to 3.1 nanograms per milliliter, and at three-month follow-up she remained well.

Beyond this single patient, the report situates the case within a rapidly evolving field. Recent studies show that calcitonin’s immunohistochemical specificity is not absolute—calcitonin-positive staining in lung tissue has occasionally masqueraded as metastatic medullary thyroid carcinoma when the real lesion was a pulmonary neuroendocrine tumor. Research on imaging decisions suggests that a 500 picograms-per-milliliter calcitonin threshold for staging scans has high sensitivity but low specificity, and that models combining calcitonin with ultrasound findings of suspicious lymph nodes perform better than any single value. On the surgical side, data from nearly 400 patients indicate that lobectomy may be a safe option in selected sporadic cases without germline RET mutations, whereas total thyroidectomy remains essential in hereditary disease. For advanced cases, a network meta-analysis found that the selective RET inhibitor selpercatinib reduced the risk of progression by ninety percent compared with placebo, outperforming older multikinase inhibitors in both efficacy and tolerability, though acquired resistance through solvent-front mutations remains an emerging challenge.

The broader lesson from this case is that medullary thyroid carcinoma can remain entirely silent until an incidental biochemical abnormality—here an isolated procalcitonin elevation rather than the expected calcitonin trigger—prompts further evaluation. For clinicians managing patients with chronic kidney disease, the message is unambiguous: biomarker elevations deserve careful, layered interpretation rather than reflexive attribution to renal impairment. As the field moves toward individualized medicine built on genetics, organoid models, and refined imaging strategies, cases like this one serve as a reminder that the first step in precision oncology is often the oldest one—paying close attention to an abnormal number on a routine laboratory report, and refusing to stop until its meaning is fully understood.

Subject of Research: A case of asymptomatic medullary thyroid carcinoma presenting with isolated procalcitonin elevation in a patient with chronic kidney disease

Article Title: Asymptomatic Medullary Thyroid Carcinoma With Isolated Carcinoembryonic Antigen Elevation in a Patient With Chronic Kidney Disease: A Case Report

Article References: Altınyüzük, O., Ediz, B., Yalın, S. F., & Parmaksız, E. (2026). Asymptomatic Medullary Thyroid Carcinoma With Isolated Carcinoembryonic Antigen Elevation in a Patient With Chronic Kidney Disease: A Case Report. Clinical Case Reports, 14(9), Article e73580. https://doi.org/10.1002/ccr3.73580

Image Credits: AI Generated

DOI: 10.1002/ccr3.73580

Keywords: medullary thyroid carcinoma, procalcitonin, calcitonin, carcinoembryonic antigen, chronic kidney disease, RET proto-oncogene, thyroidectomy, biomarkers, neuroendocrine tumors, fine-needle aspiration, selpercatinib, case report

The core of the argument rests on three epidemiological realities. First, roughly half of all canine mammary tumors are benign, meaning that any staging protocol applied indiscriminately before a diagnosis of malignancy is confirmed will expose a large share of patients to unnecessary testing. Second, a clinically relevant proportion of malignant mammary tumors are low grade and highly unlikely to metastasize, so even among dogs with cancer, many derive little benefit from systemic imaging. Third, and perhaps most strikingly, distant metastasis at the time of initial presentation appears to be genuinely rare. In data drawn from the PennVet Shelter Canine Mammary Tumor Program, only 13 of 249 dogs screened for enrollment had detectable distant metastasis, and the median tumor size in that subgroup was 6.7 centimeters, suggesting that metastasis at staging is largely a phenomenon of advanced local disease.

Despite these numbers, recent recommendations have shifted toward more elaborate pre-surgical workups, including thoracic computed tomography, abdominal ultrasound, and sentinel lymph node mapping. The authors contend that this trend is driven partly by the availability of more sensitive imaging technology and partly by a fear of missing occult metastatic lesions, a fear that has not been critically examined against actual detection rates. The consequences are not trivial. Advanced imaging adds substantial cost, requires additional anesthesia or heavy sedation, and delays definitive surgical treatment. In some cases, the accumulated expense of staging may prevent owners from pursuing the surgery that would actually cure their dog, a paradox the authors describe as directly contrary to the goal of cancer care.

To build their case, the researchers looked closely at how human breast cancer, long the conceptual model for canine mammary tumor management, handles the same question. Human breast cancer staging begins with mammography and biopsy, and only after malignancy is confirmed do clinicians proceed to sentinel lymph node biopsy, molecular typing, and, selectively, systemic imaging. Notably, guidelines from the National Comprehensive Cancer Network have evolved over the past decade in the opposite direction from veterinary practice: women with early-stage, low-risk disease based on receptor profile and sentinel lymph node status now forgo systemic imaging altogether. The rationale is that metastasis is rare in early-stage asymptomatic patients, and false-positive imaging findings automatically trigger cascades of additional diagnostics, cost, and anxiety. The canine situation, the authors argue, shares these same mathematical and psychological dynamics, yet veterinary recommendations have moved toward more testing rather than less.

Sentinel lymph node biopsy receives particularly detailed scrutiny. In human breast cancer, the technique replaced radical axillary dissection because it accurately identifies the first lymph node to receive drainage from the tumor with far less morbidity. In dogs, the anatomy is simpler: the axillary lymphocenter typically contains only one or two nodes, and the predictable drainage pattern sends the two cranial mammary glands to the axillary node and the two caudal glands to the superficial inguinal node, with the third gland draining in either direction. Reviews of lymphographic studies show that this normal pattern persists as the predominant route in most dogs with tumors, with deviations being rare and possibly linked to high tumor grade, which promotes lymphangiogenesis, inflammation, and vascular remodeling within the tumor microenvironment.

Yet the authors identify practical obstacles that make routine sentinel node biopsy in dogs problematic. Dogs commonly present with multiple independent mammary tumors, with studies reporting that 60 to 70 percent have tumors in different glands, each with its own histology and biological behavior. The largest tumor is often, but not always, the most aggressive, so selecting a single tumor for mapping risks sampling the wrong lesion, while injecting multiple tumors yields multiple biopsied nodes and larger, more painful surgeries with higher complication rates. Furthermore, because sentinel node techniques require peritumoral or subareolar contrast injection before complete resection, dogs without a confirmed diagnosis of malignancy are routinely subjected to the procedure even when their tumors turn out to be benign or low risk. The authors also note that in dogs, unlike in women, lymph node status has weak implications for chemotherapy decisions, since dogs with high-grade tumors are likely to receive systemic therapy regardless of nodal findings, making the procedure’s main human indication largely moot.

Thoracic imaging comes under similar examination. Three-view thoracic radiographs remain a reasonably sensitive, widely available, and cost-effective method that can be performed under light sedation. Computed tomography detects more small pulmonary nodules, but the clinical significance of that sensitivity is questionable in this population. In human early-stage breast cancer, the false-positive rate for chest CT, about 10 percent, actually exceeded the overall yield of metastasis detection, roughly 2 percent, a cautionary statistic for anyone considering withholding surgery based on small CT findings. Classic necropsy work by Fidler and Brodey established that pulmonary metastasis was present in 81 percent of dogs with metastatic disease, compared with only 5 to 16 percent for abdominal organs, meaning the lungs are the primary metastatic site and abdominal spread is unlikely when thoracic imaging is negative. The authors’ own prospective trial data found that every dog later confirmed at necropsy to have pulmonary metastasis had preceding three-view radiographs documenting it.

Abdominal ultrasound fares similarly in the analysis. Because the lungs dominate the metastatic pattern, the risk of metastasis confined to abdominal organs in the face of negative thoracic radiographs is low. Ultrasound also cannot reliably distinguish benign from malignant hepatic or splenic nodules, generating false positives that invite further invasive diagnostics. A large prospective screening study in healthy middle-aged and older dogs found that physical examination plus cytology of superficial masses detected the great majority of cancers, undercutting the argument that abdominal imaging is needed to catch unrelated occult tumors. Follow-up data from the authors’ earlier cohort showed that non-mammary tumors detected during monitoring emerged a median of 500 to 600 days after the original surgery, indicating they were new developments rather than lesions that staging had missed.

Fine needle aspiration of the tumors themselves is likewise judged unreliable as a screening tool. Reported sensitivity for distinguishing benign from malignant mammary lesions ranges from 25 to 95.2 percent across studies, and even modern cytological grading systems show poor concordance with histology for low-grade tumors, precisely the category where misclassification matters most for staging decisions. Because cytologists evaluate cellular atypia without the architectural context available to surgical pathologists, and because even pathologists disagree about the benign-malignant boundary in low-grade lesions across institutions and countries, the authors decline to recommend routine cytology as a gatekeeper for staging. They do concede it retains value for identifying non-mammary masses such as lipomas or mast cell tumors.

The alternative framework the authors propose is elegantly simple: let tumor size and clinical risk factors decide. For tumors under 1 centimeter, or under 3 centimeters in WHO T1 category, no pre-surgical staging is recommended; post-operative thoracic radiographs are applied by grade, skipped for grade 1, optional for grade 2, and recommended for grade 3. Tumors larger than 3 centimeters warrant pre-surgical three-view thoracic radiographs, as do any tumors with cytologically positive local nodes or obvious malignant features such as rapid growth, ulceration, or deep fixation. Routine fine needle aspiration of palpably normal regional nodes is deemed unnecessary for small tumors, since inguinal nodes are typically removed anyway with the fifth gland, but firm or enlarged nodes should always be aspirated before surgery to adjust the operative plan. Patent blue dye is endorsed for identifying axillary nodes during removal of larger cranial tumors. Abdominal ultrasound is reserved for dogs with positive inguinal nodes, to assess iliac chains, and thoracic CT is judged not indicated in most cases. The authors acknowledge that a small number of small tumors with metastatic nodes could slip through the pre-surgical net, but argue that post-operative grade assessment catches grade 2 and 3 cases. Their closing message extends beyond mammary tumors: staging recommendations across veterinary oncology should be judged by whether results change prognosis or treatment, because diagnostic intensity that offers minimal clinical benefit while imposing financial and emotional costs may ultimately harm the very patients it aims to protect.

Subject of Research: Evidence-based revision of pre- and post-surgical staging practices for canine mammary tumors

Article Title: Considerations for revised staging practices in canine mammary tumors

Article References: Sorenmo, K. U., Cofone, M. A., Donnelly, L., Duda, L., & Stefanovski, D. (2026). Considerations for revised staging practices in canine mammary tumors. Veterinary Oncology, 3(1), Article 9. https://doi.org/10.1186/s44356-026-00061-8

Image Credits: AI Generated

DOI: 10.1186/s44356-026-00061-8

Keywords: canine mammary tumors, cancer staging, veterinary oncology, sentinel lymph node biopsy, thoracic radiographs, thoracic CT, abdominal ultrasound, fine needle aspiration, tumor grade, metastasis, risk-based staging, dog health