Big Insulin-like Growth Factor 2-Producing Tumor in a Hypoglycemic Dog

Case report: Severe, refractory hypoglycemia in a 9-year-old Brittany Spaniel with renal nephroblastoma

A 9-year-old female spayed Brittany Spaniel presented for weakness and stumbling, and was diagnosed with severe hypoglycemia. An insulin to glucose ratio was not consistent with insulinoma as a cause for hypoglycemia. Diagnostic imaging (abdominal ultrasound and computed tomography) revealed a large left renal mass and a possible metastatic lesion in the right kidney. Glucagon therapy was initiated, but hypoglycemia was refractory to therapy. A left nephrectomy was performed and hypoglycemia subsequently resolved. Histopathology of the mass was consistent with nephroblastoma and immunohistochemistry for anti-insulin-like Growth Factor-2 (IGF-2) antibody revealed immunoreactivity in over 50% of the neoplastic cells. Chemotherapeutic treatment was initiated with a combined protocol of vincristine and doxorubicin. To the authors' knowledge, this is the first case report documenting the treatment of severe, refractory non-islet cell tumor-induced hypoglycemia in a dog, suspected to be secondary to an IGF-2 secreting nephroblastoma.

Rare Presentation of Hypoglycemia in a Patient with Anaplastic Large-Cell Lymphoma

Anaplastic large-cell lymphoma is a rare type of aggressive non-Hodgkin's lymphoma, and arriving at a final diagnosis for this tumor is a challenge for the healthcare providers. Usually, it involves the lymph nodes and extranodal tissues such as the lungs, skin, and other soft tissues. Its presentation by extending into different organs such as the liver, lungs, bones, spleen, and thyroid is rare. Thus, involvement of other organs is very rare as we found in a 54-year-old male patient, a known case of hypertension and end-stage renal disease who was on hemodialysis, who presented to the emergency department with a history of generalized weakness and weight loss of about 20 kg for two months. The tumor cells are positive for CD45, CD30, CD15, MUMi, and Ki-67 (80%) and negative for CD20, PAX-5, CD79a, CD3, CD5, CD10, BCL6, BCL2, EMA, ALK-1, and CD138. The patient was hypoglycemic and hypercalcemic and was managed accordingly. The patient was evaluated, and the third assessment showed that hypoglycemia was resolved due to dexamethasone. The patient's glucose storage was depleted most likely due to liver involvement plus poor general condition. It was asserted that the patient's hypoglycemia could be related to his underlying malignancy. Also, the patient was advised to start tablet diazoxide 45 mg three times a day (3 mg/kg/day TID) in addition to levothyroxine tablet 50 mcg once a day. Tablet diazoxide was stopped, and nutritional support was recommended. This case reveals a rare systematic ALK-1-negative anaplastic large-cell lymphoma that involves multiple organs. The main learning point from this report is that these tumors can present atypically even in adults and can be ALK-1 negative, which is contrary to the typical systematic anaplastic large-cell lymphomas that are positive for ALK.

Plasma concentration and uterine and ovarian expressions of insulin-like growth factor-2 in dogs with cystic endometrial hyperplasia-pyometra

The objective of this study was to investigate the plasma concentrations of insulin-like growth factor-2 (IGF-2) as well as its expression in the uterus and ovary of healthy dogs and those with cystic endometrial hyperplasia (CEH)-pyometra complex. Group 1 (n = 10) included bitches with open cervix pyometra, while Group 2 (n = 7) consisted of clinically healthy bitches in dioestrus. The number of IGF-2 immunopositive interstitial cells was significantly higher in Group 1, whereas in Group 2 there were only two cases in which a few cells were IGF-2 immunopositive. IGF-2 immunopositivity was observed in the endometrial glandular epithelium in both groups. Additionally, interstitial fibroblasts and macrophages in the endometrium were also positive in Group 1. The concentration of plasma IGF-2 was higher in Group 1 than in Group 2 (P < 0.05). The concentration was positively correlated with IGF-2 expression in the endometrial glands (r = 0.926; P < 0.001) in Group 1. However, a negative correlation was present between plasma IGF-2 concentration and IGF-2 expression in the interstitial endocrine cells of the ovary in Group 1 (r = -0.652; P < 0.05). The results suggest that IGF-2 plays an important role during the inflammatory process occurring in bitches with CEH-pyometra complex as well as in the endometrium of healthy bitches in dioestrus.

Validating Immunohistochemistry Assay Specificity in Investigative Studies: Considerations for a Weight of Evidence Approach

Immunohistochemistry (IHC) is a fundamental molecular technique that provides information on protein expression in the context of spatial localization and tissue morphology. IHC is used in all facets of pathology from identifying infectious agents or characterizing tumors in diagnostics, to characterizing cellular and molecular processes in investigative and experimental studies. Confidence in an IHC assay is primarily driven by the degree to which it is validated. There are many approaches to validate an IHC assay's specificity including bioinformatics approaches using published protein sequences, careful design of positive and negative tissue controls, use of cell pellets with known target protein expression, corroboration of IHC findings with western blots and other analytical methods, and replacement of the primary antibody with an appropriate negative control reagent. Each approach has inherent strengths and weaknesses, and the thoughtful use of these approaches provides cumulative evidence, or a weight of evidence, to support the IHC assay's specificity and build confidence in a study's conclusions. Although it is difficult to be 100% confident in the specificity of any IHC assay, it is important to consider how validation approaches provide evidence to support or to question the specificity of labeling, and how that evidence affects the overall interpretation of a study's results. In this review, we discuss different approaches for IHC antibody validation, with an emphasis on the characterization of antibody specificity in investigative studies. While this review is not prescriptive, it is hoped that it will be thought provoking when considering the interpretation of IHC results.