Insulin-secreting pancreatic (islet cell) carcinoma in a cat

Effect of diazoxide on a cat with insulinoma

Case summary

The patient was a castrated male American Shorthair cat, approximately 14 years old, weighing 3.4 kg. The patient had chronic kidney disease (CKD) (International Renal Interest Society stages 3-4) as an underlying disease. The cat was examined at a hospital for intermittent lethargy and seizures. Hypoglycaemia was repeatedly observed, and the insulin level was 1.78 ng/ml (reference interval 0.27-0.69) when the blood glucose was 49 mg/dl. Although the cat was tentatively diagnosed with insulinoma, surgery was not recommended because of the severe CKD. Although frequent feeding and prednisolone treatment were initially attempted, blood glucose decreased to 24-42 mg/dl. Diazoxide was additionally prescribed at a dose of 5.2 mg/kg q12h. The cat's clinical signs improved, and the blood glucose was in the range of 75-103 mg/dl during the first 2 months. It was maintained at >50 mg/dl until the patient died of renal failure 161 days after the start of diazoxide treatment. With regard to adverse events, vomiting once every 2-3 days without weight loss and non-regenerative anaemia were observed, which might have been at least partially caused by diazoxide treatment. An insulinoma was definitively diagnosed via pathological autopsy.

Relevance and novel information

This is the first reported case of long-term treatment with diazoxide in a cat with insulinoma. Since it was effective in situations where conventional therapies were unsuccessful, diazoxide could be useful as a new therapeutic option for cats with insulinoma. Since adverse events, such as progression of vomiting frequency and non-regenerative anaemia, were observed, careful monitoring was required during administration.

Neoplasia in captive Tsushima leopard cats (Prionailurus bengalensis euptilurus)

The Tsushima leopard cat (Prionailurus bengalensis euptilurus) is a subspecies of the mainland leopard cat that lives on the small island of Tsushima, Japan. Captive breeding has been attempted in zoos in Japan because only approximately 100 animals remain in the wild and the Tsushima leopard cat is an endangered species. There are very few reports on diseases, including tumours, of this species. We analysed the deaths of 58 Tsushima leopard cats and confirmed that nine had neoplastic disease. The average age at death of the animals with neoplasia was 14 years and tumours were the primary cause of death in all animals. Eight of the nine cases involved primary tumours of the pancreas, liver, gallbladder, tongue and salivary glands, suggesting that Tsushima leopard cats may have a predilection for digestive system tumours. This is the first report of neoplastic disease in the Tsushima leopard cat.

Retrospective study of 20 cats surgically treated for insulinoma

OBJECTIVE

To report the clinical signs, histopathology results, and prognostic factors for outcomes following excision for feline insulinoma (INS).

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Twenty client-owned cats.

METHODS

Medical records from 2006 to 2020 were reviewed by Veterinary Society of Surgical Oncology members for cats with hypoglycemia resulting from INS, with surgical excision and follow up. Clinical signs and histopathology results were summarized. Factors potentially related to disease-free interval (DFI), disease-related death (DRD), and overall survival time (OST) were analyzed with a Cox proportional hazards regression analysis.

RESULTS

All cats were hypoglycemic on presentation with neurologic signs in 18 out of 20 and inappropriate insulin levels in 12/13. Excision of insulinomas resulted in immediate euglycemia or hyperglycemia in 18 cats. Eighteen cats survived to hospital discharge. The median time to death or last postoperative follow up was 664 days (range: 2-1205 days). Prognostic factors included age at presentation (for DFI); time to postoperative euglycemia (for DRD); preoperative and postoperative serum blood glucose concentrations; metastasis at the time of surgery (DFI and DRD), and histopathologic tumor invasion (for OST). The median OST for all cats was 863 days. The 1-, 2- and 3-year survival rates were 75%, 51%, and 10%, respectively.

CONCLUSION

Excision of insulinoma resulted in euglycemia or hyperglycemia in most cats. Negative prognostic factors included young age, low serum glucose concentrations, metastasis at time of surgery, tumor invasion, and shorter time to euglycemia.

CLINICAL SIGNIFICANCE

Surgical excision resulted in survival times comparable to those of canine INS.

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat

An 11-year-old neutered male Domestic Shorthair cat presented with a 3-month history of hypoglycemia, two episodes of seizure, and intermittent tick-like signs. Serum biochemistry revealed severe hypoglycemia associated with high insulin concentrations. Dynamic abdominal computed tomography (CT) indicated two pancreatic masses, which were enhanced most during the late arterial phase but had different degrees and variations of attenuation. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed that one mass was an insulinoma and the other was an ectopic splenic tissue, consistent with the differences in imaging findings. When an intrapancreatic lesion with hyper-attenuation on dynamic abdominal CT is detected, not only insulinoma or metastasis of malignancies but also intrapancreatic accessory spleen (IPAS) should be considered as differential diagnoses.

Feline abdominal ultrasonography: What's normal? What's abnormal? The pancreas

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the pancreas is a vital part of the investigation into feline pancreatic disease.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings such as nodular hyperplasia and pathological changes such as neoplasia can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the ultrasonographic examination and appearance of the normal and diseased pancreas. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Diagnosis of insulinoma in a Maine Coon cat

Case summary

A 14-year-old male neutered Maine Coon cat presented with a 6-month history of polyphagia and one recent episode of tremors and weakness. Blood work revealed profound hypoglycemia and results of a paired insulin glucose test were consistent with an insulinoma. Abdominal ultrasound revealed a solitary pancreatic mass, and results of a fine-needle aspirate (FNA) gave further support for the location of the neuroendocrine tumor. After unsuccessful medical management of the hypoglycemia, the mass was surgically removed. Immunohistochemistry confirmed that it was an insulinoma. At the time of writing, the patient had been in clinical remission for 9 months.

Relevance and novel information

Feline insulinomas are rare and there is very little information on their behavior, clinical course and histologic characteristics. This is the first reported case of an insulinoma in a Maine Coon cat and the first to describe results of an ultrasound-guided FNA of the mass. In addition, the progression of disease, histopathology and immunohistochemistry results add to the currently minimal database for feline insulinomas.

Use of contrast-enhanced ultrasonography for the detection of a feline insulinoma

Case summary

A 14-year-old cat was presented with a 2-week history of ataxia, seizure-like episodes, vomiting and weight loss. Serum biochemistry revealed severe hypoglycaemia, associated with low serum fructosamine and high insulin concentrations. On abdominal ultrasound, a focal hypoechoic well-defined mass in the left limb of the pancreas was identified and the presence of an additional smaller nodule was suspected. Contrast-enhanced ultrasonography (CEUS) confirmed the presence of both lesions and revealed a third, even smaller nodule. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed the presence of a multifocal insulinoma. Six months later, the cat presented with tenesmus and obstipation. A colorectal adenocarcinoma was diagnosed with histopathology after partial excision of a colorectal mass. The cat was euthanased a month later owing to recurrent episodes of severe obstipation.

Relevance and novel information

This is the first clinical description of the use of CEUS in the diagnosis of feline insulinoma. Furthermore, the available scientific literature on feline insulinoma was reviewed.

Retrospective characterization of coma and stupor in dogs and cats presenting to a multicenter out-of-hours service (2012-2015): 386 animals

OBJECTIVE

To describe the signalment, etiology, and short-term outcome of dogs and cats presenting in a coma or stupor.

DESIGN

Retrospective study conducted between May 2012 and February 2015.

SETTING

Multicenter out-of-hours emergency service provider.

ANIMALS

Three hundred eighty-six patients presenting in a coma or stupor to a multicenter out-of-hours emergency care provider.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Records were reviewed to determine the most likely etiology of coma or stupor. Short-term outcomes were defined as deceased (died or euthanized) or transferred (case handed over to a daytime clinic or discharged). There were 168 dogs (coma n = 112, stupor n = 56) and 218 cats (coma n = 148, stupor n = 70) identified. Coma and stupor were more prevalent in cats compared to dogs, and Chihuahuas were over represented. Blood glucose concentrations were frequently outside established reference intervals. Excluding undetermined causes, the most common causes in dogs included traumatic brain injury (TBI) 16.0% (n = 27, deceased n = 22), hypoglycemia 10.7% (n = 18, deceased n = 8), shock 10.1% (n = 17, deceased n = 16), seizure 9.5% (n = 16, deceased n = 13), and renal or hepatic dysfunction 5.3% (n = 9, deceased n = 7). For cats, the most common causes included TBI 21.6% (n = 47, deceased n = 38), renal or hepatic dysfunction 13.3% (n = 29, deceased n = 25), intoxication 10.1% (n = 22, deceased n = 18), hypoglycemia 6.0% (n = 13, deceased n = 4), and shock 5.0% (n = 11, deceased n = 8). When treatment was attempted, 46.0% of dogs (n = 44/96) and 41.2% of cats (n = 35/85) survived to be transferred. Compared to all other etiologies, death was less likely when coma or stupor was attributed to hypoglycemia.

CONCLUSION

In cases where a cause was determined, TBI was the predominant etiology of coma and stupor for both species. With the exception of coma and stupor attributed to hypoglycemia, the overall short-term prognosis was poor.

Pathophysiology and aetiology of hypoglycaemic crises

Hypoglycaemia is a common, life-threatening complication that occurs as a component of a wide variety of disease processes. Despite its frequent occurrence, information concerning the aetiology, characteristics and outcomes of hypoglycaemic crises in veterinary medicine is limited. This review summarises the current understanding of the pathophysiology of hypoglycaemia, the body's counter-regulatory response, underlying aetiologies, diagnosis and treatment. Disease mechanisms are discussed and published evidence in veterinary literature regarding prognostic indicators, prevalence, diagnosis and treatment is examined for hypoglycaemia-related disease processes including insulinoma, glucose-lowering toxins and medications.

Ultrasonographic features of insulinoma in six ferrets

Insulinoma is a functional, insulin-secreting tumor, arising from the beta islet cells of the pancreas. It is one of the most common neoplasms in ferrets and has been associated with clinical signs of hypoglycemia, such as ptyalism, pawing at the mouth, seizures, lethargy, and coma. The ultrasonographic features of insulinoma in ferrets have not been previously reported. The purpose of this retrospective case series study was to describe the ultrasonographic features of confirmed insulinoma in a group of ferrets. Inclusion criteria were abdominal ultrasound examination and histological confirmed insulinoma by surgical biopsy. Six ferrets met the inclusion criteria, all of which had multiple hypoglycemic episodes. Ultrasonographic images were reviewed and the characteristics of the pancreatic nodules were recorded. Twenty-eight pancreatic nodules were observed in the six ferrets and were primarily hypoechoic (89.3%, 25/28) and homogenous (46.4%, 13/28) with a smooth margin (78.6%, 22/28). The distribution of the pancreatic nodules was 46.4% in the left lobe, 50% in the right lobe, and 3.6% in the body of the pancreas. The sizes of the pancreatic nodules varied from 1.5 × 1.5 to 4.1 × 5.6 mm. All of the pancreatic nodules removed from surgery were histopathologically confirmed as insulinoma. The findings indicated that insulinoma in ferrets could be detected through ultrasonography, which may facilitate diagnosis and preoperative surgical planning.

Pancreatic neuroendocrine carcinoma with exocrine differentiation in a young cat

A 35-mo-old spayed female mixed-breed cat with continuous vomiting, emaciation, and abdominal distention for 2 wk was presented to a private veterinary clinic for evaluation. At 71 d after the initial visit, the cat died with anemia, jaundice, and hypoalbuminemia, and was subjected to autopsy. Grossly, numerous firm masses, 0.5-2.5 cm diameter, were randomly located in the left lobe of the pancreas. Histologic examination revealed that the pancreatic mass consisted of 2 tumor cell types: mostly small round cells with a minority of epithelial cells. The small cells were arranged in nests of various sizes, which were separated by thin fibrous stroma, and had small, round, hyperchromatic nuclei, scant cytoplasm containing argyrophilic granules, and often formed rosettes. The epithelial cells formed luminal structures. Metastases were observed in the liver, greater omentum, and pancreatic, gastric, pulmonary, and mediastinal lymph nodes. Immunohistochemical examination revealed that the small cells were positive for vimentin, neuron-specific enolase, chromogranin A, cytokeratin (CK) AE1/AE3, and trypsin, whereas the epithelial cells were positive for AE1/AE3, trypsin, CK19, and nestin. Ultrastructurally, the small cells contained abundant electron-dense granules, ~200 nm diameter, whereas the epithelial cells had apical microvilli and numerous zymogen granules, ~300 nm diameter. These findings indicated that the tumor was a pancreatic neuroendocrine carcinoma with exocrine differentiation and systemic metastases.

Cholecystic adenocarcinoma and pancreatic insulinomas in a goat

A 13-year-old female Boer goat with a history of chronic arthritis and recurrent episodes of recumbency, increased serum gamma-glutamyl transferase, and complete inability to stand was submitted for necropsy. Gross changes included the presence of a white, firm, smooth, 6 cm × 4 cm × 3 cm mass that diffusely expanded and partially effaced the gall bladder and infiltrated the adjacent hepatic parenchyma. On cut surface, the mass was pale yellow and had small, irregular, dark yellow areas. Scattered through the pancreas were 2 gray, well-demarcated, soft, homogeneous, 1 cm in diameter nodules that bulged out from the capsular surface. The right femoral head had a locally extensive area of cartilage erosion. Histological and immunohistochemical evaluation of the gall bladder and pancreatic nodules revealed a primary cholecystic adenocarcinoma and multifocal insulinomas, respectively. A metastatic focus from the gall bladder neoplasm was observed infiltrating the right adrenal gland medulla. The goat also had mild pulmonary infestation by Muellerius capillaris. Primary hepatobiliary and pancreatic neoplasia is rare in goats, and to the authors' knowledge, neither cholecystic adenocarcinoma nor pancreatic insulinomas have been previously reported in this species.

Cellular and molecular characterization of a feline insulinoma

BACKGROUND

Insulinoma is an autonomous insulin-secreting islet cell neoplasm that is rarely diagnosed in cats. The clinical and pathological aspects of feline insulinoma have been described previously, but the molecular characteristics of these tumors have not been investigated.

OBJECTIVES

The study objectives were to characterize peptide hormone production and determine expression of selected genes involved in glucose metabolism and insulin secretion in a feline insulinoma.

METHODS

Immunohistochemistry and RT-PCR were used to examine hormone and gene expression, respectively, by insulinoma cells.

RESULTS

Immunohistochemistry examination indicated that the tumor cells expressed insulin, chromogranin A, and somatostatin but not glucagon or pancreatic polypeptide. The tumor expressed several genes characteristic of pancreatic beta cells (beta cells) including insulin (INS), glucose transporter 2 (GLUT2), and glucokinase (GCK). The tumor also expressed hexokinase 1 (HK1), a glycolytic enzyme not normally expressed in beta cells. GCK expression was higher in the insulinoma than in normal pancreas from the same cat. The GCK : HK1 ratio was >20-fold higher in insulinoma tissue than in normal pancreas.

CONCLUSIONS AND CLINICAL IMPORTANCE

The feline insulinoma produced several peptide hormones and expressed genes consistent with a beta-cell phenotype. The pattern of hexokinase gene expression in tumor cells differed from that of normal pancreas. These findings suggest insulinoma cells may have an increased sensitivity to glucose that could contribute to the abnormal insulin secretory response observed at low serum glucose concentrations.

Multiple endocrine neoplasia type I in a cat

A 13-year-old 4.6-kg (10.2-lb) neutered male domestic long hair cat was evaluated because of a history of lethargy, exercise intolerance, and ventroflexion of the cervical portion of the vertebral column. After extensive assessment at the Veterinary Teaching Hospital at Michigan State University, the clinical signs were attributed to an aldosterone-secreting tumor of the adrenal gland. Subsequently, an insulin-secreting tumor of the pancreas as well as a functional parathyroid gland adenoma were diagnosed. All 3 masses were surgically removed, and the cat made a full recovery with complete resolution of clinical signs. The syndrome of multiple endocrine neoplasia is well described in humans, and the heritability of the condition has been confirmed. In cats and other species with 1 or more endocrine neoplasms, it is important to perform thorough clinical assessments of patients to identify other endocrine organs that may also be affected concurrently with neoplastic disease.

Hypoglycemia and irreversible neurologic complications in a cat with insulinoma

A 14-year-old spayed female domestic shorthair cat was evaluated for weakness, lethargy, decreased appetite, diarrhea, weight loss, and seizures. On physical examination, the cat appeared disoriented and had an inconsistent menace response. An insulinoma was diagnosed on the basis of normal serum insulin activity in conjunction with profound hypoglycemia and histologic examination (with immunohistochemical staining for chromogranin A and insulin) of a pancreatic mass that was removed surgically. Blood glucose concentration was within reference limits after surgery. However, neurologic abnormalities persisted, and the cat was euthanatized. Chronic hypoglycemia, associated with insulinomas, can cause irreversible neuronal changes in cats; therefore, rapid diagnosis and treatment of hypoglycemic conditions are of critical importance.

Endocrine tumors

Because of the diverse nature of endocrine organs, and their vast range of physiologic functions, endocrine tumors encompass a wide range of origination sites and disease entities. The clinical picture of affected individuals is highly dependent on the tissue of origin, and the presence or absence of functional hormone secretions. Identification, localization, and therapeutic strategies, as well as prognosis can vary greatly. Many endocrine tumors have been described in human as well as veterinary patients. This article focuses on endocrine tumors of dogs and cats. Various tumors affecting the pancreas, thyroid, parathyroid, adrenal and pituitary glands are described, including insulinoma, gastrinoma, glucagonoma, and thyroid carcinoma, as well as parathyroid hormone- and growth hormone-secreting tumors. The syndrome of multiple endocrine neoplasia is also described.

Feline epilepsy

The diagnosis and management of seizures in the cat require an understanding of the more common diseases that predispose to feline epilepsy. Feline seizures may occur secondary to intracranial or extracranial disease. Intracranial causes include inflammatory, neoplastic, vascular, and traumatic disorders. Extracranial causes include various metabolic and toxic insults. Previous brain insults that are no longer active may leave "seizure foci." Idiopathic epilepsy is uncommon in the cat relative to the dog but should be considered if no cause can be found. Regardless of the etiology, ictal events in cats can manifest themselves in multiple forms and levels of severity. Therapy should be directed at controlling seizure frequency and treating the underlying cause. An aggressive diagnostic and therapeutic approach to feline epilepsy may improve prognosis and lead to a favorable outcome.

Immunohistochemistry of pancreatic islet cell tumors in the ferret (Mustela putorius furo)

Twenty-two pancreatic islet cell tumors and normal pancreatic islets from ferrets were evaluated by immunohistochemistry for expression of the peptide hormones insulin, somatostatin, glucagon, and pancreatic polypeptide (PP) and the neuroendocrine markers chromogranin A (CgA) and neuron-specific enolase (NSE). In normal pancreatic islets, the majority of cells stained strongly with CgA and NSE. A cells, B cells, D cells, and PP cells stained strongly with glucagon, insulin, somatostatin, and PP, respectively. All 22 tumors stained with CgA and NSE. The proportion of cells within tumors staining for CgA was variable, but more than half of the cells stained positively in 18 of the tumors. The intensity of staining for CgA was strongly (reactivity equivalent to or greater than normal islet cells in adjacent tissue) in 11 moderate in six, and weak in five of the tumors. All tumors stained for NSE, with > or = 50% of the cells staining in 21 of the tumors, and the intensity of staining was strong in 18 of the tumors. Twenty of 22 tumors stained positively for insulin. with > or = 50% of the cells staining in 19 of them. The intensity of staining for insulin was strong in 12, moderate in seven, and weak in one of the tumors. Approximately < or = 1% of the cells in 15 of 22 tumors stained for somatostatin, five tumors stained for pancreatic polypeptide, and three tumors stained for glucagon. These data indicate that the majority of islet cell tumors of ferrets express immunohistochemically detectable insulin. CgA and NSE are both useful general markers for such tumors, including those that are insulin negatives. Commercially available antisera to CgA, NSE, insulin, glucagon, somatostatin, and PP work well in formalin-fixed, paraffin-embedded tissue for immunophenotyping islet cell tumors in the ferret.