Cytochrome b5 expression in gonadectomy-induced adrenocortical neoplasms of the domestic ferret (Mustela putorius furo)

Whereas the adrenal glands of healthy ferrets produce only limited amounts of androgenic steroids, adrenocortical neoplasms that arise in neutered ferrets typically secrete androgens or their derivative, estrogen. The 17,20-lyase activity of cytochrome P450 17alpha-hydroxylase/17,20-lyase (P450c17) must increase to permit androgen biosynthesis in neoplastic adrenal tissue. We screened ferret adrenocortical tumor specimens for expression of cytochrome b(5) (cyt b(5)), an allosteric regulator that selectively enhances the 17,20-lyase activity of P450c17. Cyt b(5) immunoreactivity was evident in 24 of 25 (96%) adrenocortical adenomas/carcinomas from ferrets with signs of ectopic sex steroid production. Normal adrenocortical cells lacked cyt b(5), which may account for the low production of adrenal androgens in healthy ferrets. Other markers characteristic of gonadal somatic cells, such as luteinizing hormone receptor, aromatase, and GATA4, were coexpressed with cyt b(5) in some of the tumors. We concluded that cyt b(5) is upregulated during gonadectomy-induced adrenocortical neoplasia and is a marker of androgen synthetic potential in these tumors.     

ADRENAL NEOPLASIA IN SEVEN FERRETS

Medical records from 7 ferrets presented to the VMTH with histologically confirmed adrenal neoplasia were reviewed. Three neutered female ferrets had adrenal cortical adenoma; four ferrets (2 neutered females, 2 neutered males) had adrenal cortical carcinoma. Ultrasound identified unilateral enlargement or abnormal shape of the adrenal gland in all ferrets. Only 1 ferret had adrenomegaly on abdominal radiographs. Adrenomegaly was identified in 1 ferret by magnetic resonance imaging (MRI). All ferrets were treated by adrenalectomy followed by a tapered dose of prednisone. Surgical complications were limited to fatal hemorrhage from the caudal vena cava in 1 ferret. Remission of clinical signs occurred in all 6 ferrets which survived surgery. The time of follow up varied from 3 to 16 months. The 3 ferrets with adrenal adenomas were still alive 3 to 7 months after surgery. AH 3 ferrets with adrenal carcinoma developed metastasis and were euthanized from 2 to 16 months after surgery.     

Characterization of spindle cell component of ferret (Mustela putorius furo) adrenal cortical neoplasms – correlation to clinical parameters and prognosis

Adrenal cortical epithelial tumours are common in ferrets. A variant tumour type with prominent spindle cell proliferation has been identified. We characterized these variant tumours with light microscopy and immunohistochemical analysis and correlate these features to clinical parameters and prognosis. We classified 24 ferret adrenal cortical masses with recognizable spindle cell proliferation obtained from the AMC and AFIP databases, based on percentage of spindle cells present and features of malignancy. These masses were separated into hyperplastic nodules and adenomas (both with 1–24% spindle cells), ‘mixed’ adenomas (≥25% spindle cells), adenocarcinomas (1–24%) and ‘mixed’ adenocarcinomas (≥25% spindle cells). Tumours were evaluated immunohistochemically for smooth muscle actin (SMA) and estrogen receptor (ER) expression. Disease‐free interval (DFI) and survival time (ST) were calculated using Kaplan–Meier product limit method. Of 24 cases of spindle cell variant adrenal tumours, one was a hyperplastic nodule, 10 were adenomas, three were ‘mixed’ adenomas, six were adenocarcinomas and four were ‘mixed’ adenocarcinomas. The proliferative spindle cell cytoplasm was SMA‐positive (smooth muscle myocyte origin). ER positivity, seen in nine of 24 cases, was restricted to adenocarcinomas, ‘mixed’ adenomas and ‘mixed’ adenocarcinomas. DFI and ST were significantly reduced in ‘mixed’ adenocarcinomas or tumours with ER expression. DFI was significantly reduced in tumours with marked smooth muscle. The spindle cell component of these variant adrenal tumours is smooth muscle in origin. The presence of abundant smooth muscle, a more malignant histologic grade (‘mixed’ adenocarcinomas) and ER expression are significantly positively correlated to both decreased DFI and decreased ST.     

Effects of melatonin administration on the clinical course of adrenocortical disease in domestic ferrets

OBJECTIVE: To evaluate the effect of oral administration of melatonin on clinical signs, tumor size, and serum steroid hormone concentrations in ferrets with adrenocortical disease. DESIGN: Noncontrolled clinical trial. ANIMALS: 10 adult ferrets with clinical signs of adrenocortical disease (confirmed via serum steroid hormone concentration assessments). PROCEDURES: Melatonin (0.5 mg) was administered orally to ferrets once daily for 1 year. At 4-month intervals, a complete physical examination; abdominal ultrasonographic examination (including adrenal gland measurement); CBC; serum biochemical analyses; and assessment of serum estradiol, androstenedione, and 17alpha-hydroxyprogesterone concentrations were performed. Serum prolactin and dehydroepiandrosterone sulfate concentrations were evaluated at the first, second, and last examinations, and serum cortisol concentration was evaluated at the first and last examinations. RESULTS: Daily oral administration of melatonin greatly affected clinical signs of adrenocortical disease in ferrets; changes included hair regrowth, decreased pruritus, increased activity level and appetite, and decreased vulva or prostate size. Mean width of the abnormally large adrenal glands was significantly increased after the 12-month treatment period. Recurrence of clinical signs was detected in 6 ferrets at the 8-month evaluation. Compared with pretreatment values, serum 17alpha-hydroxyprogesterone and prolactin concentrations were significantly increased and decreased after 12 months, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that melatonin is a useful, easily administered, palliative treatment to decrease clinical signs associated with adrenocortical disease in ferrets, and positive effects of daily treatment were evident for at least an 8-month period. Oral administration of melatonin did not decrease adrenal gland tumor growth in treated ferrets.     

Leuprolide acetate treatment of adrenocortical disease in ferrets

OBJECTIVE: To determine the effects of leuprolide acetate, a long-acting gonadotropin-releasing hormone analog, in ferrets with adrenocortical diseases. DESIGN: Case series. ANIMALS: 20 ferrets with adrenocortical disease diagnosed on the basis of clinical signs and plasma sex hormone concentrations. PROCEDURE: Ferrets were treated with leuprolide (100 microg, IM, once), and plasma hormone concentrations were measured before and 3 to 6 weeks after treatment. RESULTS: Leuprolide treatment resulted in significant reductions in plasma estradiol, 17 alpha-hydroxyprogesterone, androstenedione, and dehydroepiandrosterone concentrations and eliminated or reduced clinical signs associated with adrenocortical disease. Decreases in vulvar swelling, pruritus, and undesirable sexual behaviors and aggression were evident 14 days after treatment; hair regrowth was evident by 4 weeks after treatment. The response to treatment was transitory, and clinical signs recurred in all ferrets. Mean +/- SEM time to recurrence was 3.7 +/- 0.4 months (range, 1.5 to 8 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that leuprolide can be safely used to temporarily eliminate clinical signs and reduce sex hormone concentrations in ferrets with adrenocortical diseases. However, the safety of long-term leuprolide use in ferrets has not been investigated, and the long-term effects of leuprolide in ferrets with nodular adrenal gland hyperplasia or adrenal gland tumors are unknown.     

Clinical and endocrine responses to treatment with deslorelin acetate implants in ferrets with adrenocortical disease

OBJECTIVE: To evaluate the clinical and endocrine responses of ferrets with adrenocortical disease (ACD) to treatment with a slow-release implant of deslorelin acetate. ANIMALS: 15 ferrets with ACD. PROCEDURE: Ferrets were treated SC with a single slow-release, 3-mg implant of deslorelin acetate. Plasma estradiol, androstenedione, and 17-hydroxyprogesterone concentrations were measured before and after treatment and at relapse of clinical signs; at that time, the adrenal glands were grossly or ultrasonographically measured and affected glands that were surgically removed were examined histologically. RESULTS: Compared with findings before deslorelin treatment, vulvar swelling, pruritus, sexual behaviors, and aggression were significantly decreased or eliminated within 14 days of implantation; hair regrowth was evident 4 to 6 weeks after treatment. Within 1 month of treatment, plasma hormone concentrations significantly decreased and remained decreased until clinical relapse. Mean time to recurrence of clinical signs was 13.7 +/- 3.5 months (range, 8.5 to 20.5 months). In 5 ferrets, large palpable tumors developed within 2 months of clinical relapse; 3 of these ferrets were euthanatized because of adrenal gland tumor metastasis to the liver or tumor necrosis. CONCLUSIONS AND CLINICAL RELEVANCE: In ferrets with ACD, a slow-release deslorelin implant appears promising as a treatment to temporarily eliminate clinical signs and decrease plasma steroid hormone concentrations. Deslorelin may not decrease adrenal tumor growth in some treated ferrets. Deslorelin implants may be useful in the long-term management of hormone-induced sequelae in ferrets with ACD and in treatment of animals that are considered at surgical or anesthetic risk.     

Exocrine pancreatic carcinoma and carcinomatosis with abdominal effusion containing mast cells in a ferret (Mustela putorius furo).

This case describes the clinical presentation and findings of exocrine pancreatic carcinoma in a 9-year-old female sprayed ferret (Mustela putorius furo). Transcoelomic metastasis and hemorrhagic abdominal effusion were secondary to the neoplasm. The finding of mast cells in abdominal effusion, with a leukocyte component composed primarily of lymphocytes and lesser numbers of neutrophils and macrophages, is an atypical finding, never before reported in ferrets.     

Immunoreactivity of A103, an antibody to Melan A, in canine steroid-producing tissues and their tumors.

The monoclonal antibody A103 to the melanocytic differentiation antigen Melan A stains human steroid-producing cells and their tumors. A total of 200 formalin-fixed, paraffin-embedded canine normal tissues and hyperplastic and neoplastic lesions of the adrenal gland, testis, and ovary were immunohistochemically tested for Melan A with antibody A103. Leydig cell tumors (23/23, 100%), Sertoli cell tumors (14/15, 93%), and adrenocortical adenomas (12/13, 92%) were consistently positive. Adrenocortical carcinomas (23/35, 65%) and granulosa cell tumors (10/17, 59%) were less frequently positive. All pheochromocytomas, seminomas, and dysgerminomas were negative. The pattern of staining was cytoplasmic, but nuclear staining was also frequently seen in normal Leydig cells and their tumors. As in human tumors, immunohistochemistry for Melan A stains many canine steroid-producing tumors and can be used to distinguish these tumors from those of nonstereidogenic cells.     

A Case of Metastatic Adrenocortical Carcinoma Diagnosed with Steroidogenic Factor-1 in a Sprague-Dawley Rat

This report describes the morphological and immunohistochemical characteristics of an adrenocortical carcinoma with distant metastasis in a Sprague-Dawley rat. Macroscopically, a single large mass was observed in the adrenal gland, and multiple nodules were noted in the lung, liver and thyroid. Histologically, the adrenal tumor consisted of a solid growth of eosinophilic round cells with nuclear atypia. Vascular invasion was present, and multiple metastatic lesions were also observed in the lungs, liver, and mediastinal lymph nodes. Immunohistochemically, the nuclei of these tumor cells were positive for Steroidogenic Factor-1 (SF-1). In the thyroid, tumor cells histologically resembling adrenal cells were immunohistochemically negative for SF-1 but positive for calcitonin; thus the lesion was diagnosed as thyroid C-cell carcinoma. From these results, the present case was diagnosed as adrenocortical carcinoma with distant metastases. SF-1 could be a valuable marker for the differential diagnosis of adrenocortical tumors versus other endocrine tumors such as C-cell carcinoma.     

Round cell variant of myxoid liposarcoma in a Japanese Macaque (Macaca fuscata)

A 5-year-old, female, Japanese Macaque (Macaca fuscata) was diagnosed with round cell variant of myxoid liposarcoma. At necropsy, multifocal to coalescing, reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum. Similar neoplastic nodules were also present in diaphragm, abdominal wall, and on hepatic capsule. Microscopically, neoplastic masses consisted of round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm. Ultrastructurally, the cytoplasm of the tumor cells was packed with occasional lipid vacuoles and numerous enlarged mitochondria. Immunohistochemistry revealed tumor cells were positive for vimentin, while negative to cytokeratin, actin, and Factor VIII-related antigen. To the authors' knowledge, this is the first report of round-cell variant of myxoid liposarcoma in nonhuman primate.     

RETROSPECTIVE REVIEW OF THE ULTRASONOGRAPHIC FEATURES OF ADRENAL LESIONS IN 21 FERRETS

Clinical signs and follow-up information were recorded. Histopathologic diagnoses were obtained for 25 adrenal glands in 21 ferrets. Adrenal lesions included ten adenocarcinomas, nine adenomas, one hyperplasia and one cortical cyst. Four adrenal glands (all right-sided) were diagnosed as unspecified adrenal tumors but lacked a definite histopathologic diagnosis (adenoma vs. adenocarcinoma) due to incomplete surgical resection and consequent small sample sizes. Bilateral adrenal lesions were identified in 4 ferrets (19%). Adrenal shape, size, echogenicity, laterality, and the presence of vascular invasion were evaluated with ultrasound. Size and shape were variable and not specific to lesion type. Both benign and malignant adrenal tumors (adenomas, adenocarcinomas) appeared most often as masses with increased thickness and a normal length (11/23), less frequently as larger masses with increased thickness and length (4/23) or as nodules focally deforming the normal adrenal shape (6/23). The only cortical cyst appeared as a nodule. Three adrenal glands had a normal size and shape and were diagnosed as adenomas (2) or hyperplasia (1). Therefore treatment may be warranted based solely on clinical signs if adrenal glands are ultrasonographically normal. Vascular invasion was not identified ultrasonographically. However, focal absence of periglandular fat resulting in contact of 8 adrenal glands with either caudal vena cava (6), aorta (1) or liver (1) identified ultrasonographically, correlated with incomplete surgical resectability (6/8) and histopathologic diagnoses of carcinoma (4/8) or unspecified tumors (4/8). Therefore, a focal absence of periglandular fat between the adrenal gland and the large vessels or liver, deviation or compression of the large vessels by the adrenal lesion may indicate malignancy. Adrenal tumors (benign and malignant) were often associated with a prominent uterus, uterine stump or prostate with or without prostatic cysts.     

Indicators of malignancy of canine adrenocortical tumors: histopathology and proliferation index

Tumors of the adrenal cortex account for 10-20% of the naturally occurring Cushing's syndrome diagnosed in dogs. Differentiating between adrenocortical adenoma and carcinomas is often difficult. The purposes of this study were to determine which histopathologic criteria can be used as markers for malignancy in canine adrenocortical tumors and the relevance of the proliferation marker, Ki-67, for differentiation between cortical adenomas and carcinomas. Twenty-six adrenocortical carcinomas, 23 adenomas, and 11 normal adrenal glands were examined. Morphologic criteria significantly associated with adrenocortical carcinomas included a size larger than 2 cm in diameter, peripheral fibrosis, capsular invasion, trabecular growth pattern, hemorrhage, necrosis, and single-cell necrosis, whereas hematopoiesis, fibrin thombi, and cytoplasmic vacuolation were significantly associated with adrenocortical adenomas. The mean (+/- SD) proliferation index, measured by immunohistochemistry for the Ki-67 antigen, was 9.3 +/- 6.3% in carcinomas, 0.76 +/- 0.83% in adenomas, and 0.58 +/- 0.57% in normal adrenal glands. The Ki-67 proliferation index was significantly higher in carcinomas compared with adenomas and normal adrenal glands. A threshold value of the proliferation index of 2.4% reliably separated carcinomas from adenomas. Based on these results, it appears that thorough evaluation of morphologic features combined with immunohistochemical assessment of the proliferation index is extremely useful for differentiating between adrenocortical adenomas and carcinomas in dogs.     

Secretory carcinoma of the canine mammary gland

Secretory carcinoma is an uncommon variant of breast cancer, characterized by the presence of intracellular and extracellular eosinophilic secretion. Here, we report the cytologic, histologic, and immunohistochemical findings of a secretory carcinoma diagnosed in the left inguinal mammary gland of a 3-year-old female German Shepherd Dog. The fine-needle aspiration cytology showed numerous large branching sheets of neoplastic cells and isolated cells with cytoplasmic vacuoles. Histologically, the tumor was composed of cells with clear cytoplasm and prominent vacuoles that pushed the nuclei to the periphery, resembling signet ring cells. These cells were arranged in solid or tubular structures with lumenal spaces filled with eosinophilic secretion. Immunohistochemical reactions to cytokeratin (CAM 5.2) and alpha-lactalbumin were strongly positive in all neoplastic cells, and staining for vimentin and S100 protein was negative. The cytomorphologic and immunohistochemical features of this tumor are similar to those seen in tumors in women, hence enabling the diagnosis of a rare case of primary secretory carcinoma of the canine mammary gland.     

Results of surgical treatment for hyperadrenocorticism caused by adrenocortical neoplasia in the dog: 25 cases (1980-1984)

Results of surgical treatment for neoplasia of the adrenal cortex that caused hyperadrenocorticism were evaluated in 25 dogs. Surgical examination of the adrenal glands was performed by use of a ventral midline approach in 24 dogs and a retroperitoneal approach in 1 dog. All 25 dogs had a unilateral, adrenocortical tumor. Histologic examination identified 14 adrenocortical carcinomas and 11 adenomas. Seven dogs with carcinoma had visible metastasis to the liver, 3 had local invasion into the caudal vena cava, and 1 had extension into the adjacent renal vein. Seven of the 9 dogs with metastasis were euthanatized at time of surgery. Of the remaining 18 dogs that survived surgery, 9 (4 with carcinoma and 5 with adenoma) developed serious postoperative complications including acute renal failure, pneumonia, and pulmonary artery thromboembolism; 8 of these dogs died or were euthanatized. Of the remaining 10 dogs, clinical signs associated with hyperadrenocorticism resolved in the 7 dogs that had adrenocortical adenoma and in 1 of the 3 dogs that had carcinoma. The remaining 2 dogs with carcinoma had persistent hyperadrenocorticism and were treated with high doses of mitotane. Although no response was observed in 1 dog with visible hepatic metastasis, a decrease in serum cortisol concentrations and resolution of clinical signs were detected in the other dog during prolonged daily administration of mitotane.     

Renal tubular-cell neoplasms in black-footed ferrets (Mustela nigripes)--38 cases

Thirty-eight cases of renal tubular cell neoplasms were diagnosed in 184 captive, adult (>1-year-old), black-footed ferrets (Mustela nigripes) examined from 1985 to 1996. This prevalence (20.7%) is one of the highest reported for this neoplasm in a population of animals. These tumors rarely metastasized (1/38), and usually were incidental postmortem findings, associated clinical disease being present in only 3 (8%) of the 38 cases. The prevalence of renal tubular cell neoplasms found at postmortem examination increased linearly with age, up to 67% in ferrets >8 years old. Both males (prevalence = 19%) and females (prevalence = 24%) were affected. Multiple renal tumors were common, and seven ferrets (18.4% of affected animals) had bilateral tumors. The cause of this neoplastic syndrome could not be determined. Since most of the animals affected by this condition were in their postreproductive years of life, the impact of this neoplastic syndrome on the captive propagation of this species is negligible.     

Intestinal haemangiosarcoma in the cat: clinical and pathological features of four cases

The clinical and pathological features of four cases of feline intestinal haemangiosarcoma are described. All cases were in domestic shorthaired cats and the mean age of the animals (n=3) was 13 years. The tumours originated in the colon, small intestine, ileocaecocolic junction or rectum. The rectal tumour was juxtaposed with an adjacent mast cell neoplasm. Metastasis to mesenteric lymph node occurred in two cases, and in one of these cats there was also abdominal seeding. The histopathological appearance was of a spindle cell neoplasm with vascular differentiation in each case. Immunohistochemical staining for factor VIII-related antigen, an endothelial cell marker, confirmed all four tumours to be of endothelial origin. The neoplastic endothelial cells lining irregular vascular channels were more likely to express the antigen than those forming denser sheets without obvious vascular differentiation.     

Cutaneous extraskeletal mesenchymal chondrosarcoma in a cat

A 4-year-old, male cat was presented with a fixed, subcutaneous mass in the lumbosacral region. A histopathological examination revealed a well-defined but nonencapsulated neoplasm characterized by a proliferation of predominantly spindle cells, with high mitotic activity. Interspersed between these cells were single cellular elements with chondroid differentiation. Large areas of cartilaginous tissue with foci of endochondral ossification, necrosis and myxoid tissue were also observed within the neoplastic parenchyma. A diagnosis of extraskeletal mesenchymal chondrosarcoma was made based on the histological pattern - characterized by the coexistence of cartilaginous islands and undifferentiated mesenchymal cells, results of Alcian blue staining at various pH, immunohistochemical reactivity against vimentin and S-100, and the absence of skeletal involvement or other primary tumour sites. Clinical history of the cat excluded traumas, vaccinations or other types of subcutaneous inoculation. Six months on from surgical treatment, neither recurrence nor metastases have been detected.