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Biomedical subjects

A K Patnaik

Publications and source records attributed to A K Patnaik.

At least 19 recordsLinked to original sources
PubMed2000

Radiation treatment for incompletely resected soft-tissue sarcomas in dogs.

OBJECTIVE: To evaluate efficacy of radiation for treatment of incompletely resected soft-tissue sarcomas in dogs. DESIGN: Prospective serial study. ANIMALS: 48 dogs with soft-tissue sarcomas. PROCEDURE: Tumors were resected to < 3 cm3 prior to radiation. Tumors were treated on alternate days (three 3-Gy fractions/wk) until 21 fractions had been administered. Cobalt 60 radiation was used for all treatments. RESULTS: Five-year survival rate was 76%, and survival rate was not different among tumor types or locations. Four (8%) dogs developed metastases. Eight (17%) dogs had tumor recurrence after radiation. Development of metastases and local recurrence were significantly associated with reduced survival rate. Median survival time in dogs that developed metastases was 250 days. Median disease-free interval for all dogs was 1,082 days. Median time to recurrence was 700 days. Dogs that developed recurrence after a prolonged period responded well to a second surgery. Acute radiation toxicosis was minimal; osteosarcoma developed at the radiation site in 1 dog. CONCLUSIONS AND CLINICAL RELEVANCE: An excellent long-term survival rate may be achieved by treating soft-tissue sarcomas in dogs with resection followed by radiation. Amputation is not necessary for long-term control of soft-tissue sarcomas in limbs. Development of metastases and recurrence of local tumors after radiation treatment are associated with decreased survival rate. Acute and delayed radiation toxicosis was minimal with the protocol used in this study.

Animals↗
PubMed1999

Hypoadrenocorticism as the primary manifestation of lymphoma in two cats.

Hypoadrenocorticism secondary to bilateral lymphomatous invasion of adrenocortical tissue was diagnosed in 2 adult castrated domestic shorthair cats. In both cats, findings during initial physical examination (ie, lethargy, anorexia, weight loss, and severe weakness) were consistent with severe hypoadrenocorticism. Hyperkalemia, hyponatremia, and azotemia were also detected, which were consistent with hypoadrenocorticism. Hypoadrenocorticism was documented on the basis of finding low baseline and ACTH-stimulated serum cortisol concentrations. The cats initially responded well to treatment, but both owners chose to have the cat euthanatized. Multicentric lymphoma with infiltration and destruction of the adrenal glands was confirmed during necropsy.

Adrenal Cortex Neoplasms↗
PubMed1997

Malignant colonic neoplasia in cats: 46 cases (1990-1996).

OBJECTIVE: To evaluate a group of cats with malignant colonic neoplasia and to identify factors related to survival time. DESIGN: Retrospective study. ANIMALS: 46 cats with malignant colonic neoplasia. PROCEDURE: Information on signalment, diagnostic findings, histopathologic diagnosis, surgical procedure performed, identification of nodal metastasis at surgery, type of chemotherapy administered, and survival time was obtained from the medical record of each cat. A diagnosis of malignant colonic neoplasia had been established by histologic examination of endoscopic biopsy specimens (3 cats), biopsy specimens obtained during laparotomy (38), or necropsy specimens (5). RESULTS: Mean age of cats was 12.5 years (range, 6 to 18 years). Ultrasonography was useful 84% of the time in localizing the mass to the intestine. Three cats had endoscopic biopsy, 9 had incisional biopsy, 21 had mass resection, and 8 had subtotal colectomy performed. Histopathologic diagnoses included adenocarcinoma (21 cats), lymphoma (19), mast cell tumor (4), and neuroendocrine carcinoma (2). CLINICAL IMPLICATIONS: Obtaining clean margins at surgery seems to increase survival time in cats with malignant colonic neoplasia. Metastasis at the time of surgery decreases survival time. Data from this study indicate that the survival time of certain cats with colonic lymphoma may not be affected by chemotherapy. Cats with an unidentified colonic mass should receive a subtotal colectomy to increase survival time. Cats with colonic adenocarcinoma should receive a subtotal colectomy with consideration of doxorubicin administration to increase survival time.

Adenocarcinoma↗
PubMed1997

Nonlymphoid vertebral canal tumors in cats: 11 cases (1987-1995).

OBJECTIVE: To determine outcome of cats with nonlymphoid tumors of the vertebral canal that undergo surgery. DESIGN: Retrospective study. ANIMALS: 11 cats. PROCEDURE: Information obtained from the medical records included signalment, tumor location, gross evaluation of completeness of surgical excision, histologic diagnosis, and survival time. RESULTS: Median age of cats was 12 years: all cats had negative FeLV and feline immunodeficiency virus test results. All cats underwent a hemilaminectomy or dorsal laminectomy. The tumor was located in the thoracic portion of the vertebral column in 6 cats. Six cats had intradural-extramedullary tumors. Tumors included meningioma (n = 5), malignant nerve sheath tumors (2), and meningeal sarcoma, chondrosarcoma, lipoma, and osteosarcoma (1 each). One cat was lost to follow-up, 1 cat with meningioma was alive 1,400 days after surgery, and 1 cat with a nerve sheath tumor was alive 2,190 days after surgery. Median survival time for the other 4 cats with meningioma was 180 days (range, 30 to 600 days). CLINICAL IMPLICATIONS: Cats with nonlymphoid vertebral canal tumors that undergo surgery may have a good prognosis.

Age Factors↗
PubMed1993

Histologic and immunohistochemical studies of granular cell tumors in seven dogs, three cats, one horse, and one bird.

In a retrospective study, granular cell tumors in six dogs (Nos. 1-6), three cats (Nos. 1-3), one horse (No. 1), and one cockatiel (Nymphicus hollandicus) (No. 1) and a meningioma with a granular cell component in one dog (No. 7) were examined histologically and immunohistochemically. These tumors were identified by histologic examination of surgical biopsy specimens, except in the horse, in which the tumor was an incidental finding at necropsy. These diagnoses were initially made by more than one pathologist. Five of the six granular cell tumors in the dogs were in the oral cavity; one of these was in the maxillary gingiva of a 6-month-old puppy. The tumors in the cats were located in the tongue, vulva, and digit. The tumor in the horse was in the lung, and the tumor in the cockatiel was in the periocular tissue. Histologically, all granular cell tumors were characterized by oval to polygonal cells of various sizes. The cells had abundant, pale, eosinophilic cytoplasm with distinct intracytoplasmic granules, distinct cell margins, and mostly central nuclei. In the dogs, the gingival tumor had a large amount of collagen tissue, the tumor in the tongue had dilated blood vessels, and the maxillary tumor in the puppy was more cellular than the other tumors. The tumors in the cats were more anaplastic than the other tumors; one, located in the digit, was considered malignant. The granules in all of the tumors stained with periodic acid-Schiff and were diastase resistant. On staining with Luxol fast blue, the granules of all tumors stained different shades of pink, with the exception of the tumor in the tongue of a cat, which stained bluish green. Immunocytochemically, all tumors except the tumor in the cockatiel reacted against antibodies to vimentin. The granular cell tumor in the lung of the horse and the intracranial meningioma in a dog reacted to the antibody S-100 protein; the tumor in the horse reacted to neuron-specific enolase; tumors in two dogs (gingiva and skin) reacted to L-antitrypsin, and the maxillary tumor also reacted to lysozyme; the malignant tumor in the digit of a cat and the periocular tumor in the cockatiel reacted to muscle common actin and actin; the tumor in the cockatiel also reacted to desmin. Results of these immunocytochemical studies suggest that granular cell tumors, like tumors composed of rhabdoid cells, clear cells, and oncocytes, can have similar morphologic features but be of different cellular origins.

Animals↗
PubMed1993

A clinicopathologic, histologic, and immunohistochemical study of mixed germ cell-stromal tumors of the testis in 16 dogs.

In a review of 262 neoplasms in 225 dogs, 18 tumors in 16 dogs were mixed germ cell-stromal tumors containing intimately admixed germ cells and Sertoli cells in tubular structures of various sizes. Seven of the 18 neoplasms were predominantly composed of germ cells, and 11 were predominantly composed of Sertoli cells. In 15 neoplasms, the germ cells were more anaplastic than the Sertoli cells, and in three neoplasms, both cell types were anaplastic. Five of the seven mixed-cell tumors with predominantly germ cells had germ cells infiltrating the adjoining tissues. Immunocytochemical studies of all 18 mixed-cell tumors, testes from five clinically normal dogs, six seminomas, and six Sertoli cell tumors revealed that neuron specific enolase (NSE) and vimentin were useful in demonstrating the dual population of the mixed cell tumors by differential staining of the germ cells and Sertoli cells. Half of the tumors stained differentially with desmin. In the normal testes, seminomas, and Sertoli cell tumors, parallel staining of germ cells and Sertoli cells by NSE and vimentin was seen, but only the appropriate tissues stained with desmin. The mixed-cell tumors in this study had morphologic features in common with mixed germ cell-sex cord stromal tumors and gonadoblastomas of human beings; clinically, they had more in common with the former. These mixed cell tumors in dogs should be classified separately.

Animals↗
PubMed1992

Malignant anterior uveal melanoma with diffuse metastasis in a dog.

Enucleation was performed in 10-year-old sexually intact female mixed-breed German Shepherd Dog. Histologic examination revealed that the dog had an uveal amelanotic melanoma of the eye. The tumor consisted of anaplastic cells with a high mitotic index, indicating malignancy. On examination 3 months after enucleation, the dog had difficulty breathing and nasal discharge. Radiography revealed pulmonary metastasis. The dog was euthanatized. Necropsy revealed diffuse metastasis involving various organs.

Animals↗
PubMed1992

Nonhematopoietic hepatic neoplasms in cats: 21 cases (1983-1988).

Nonhematopoietic hepatic neoplasms (n = 25) were diagnosed in 21 cats during a 5.5-year period. Thirteen of the neoplasms were benign bile duct adenomas and 12 were malignant, 6 of which were bile duct adenocarcinomas. All cats were greater than or equal to 10 years old, and 14 were male. Main clinical signs were anorexia and lethargy, and 15 of 21 cats had hepatomegaly. All 21 cats were feline leukemia virus-test negative. Although there was a trend toward high activities of serum alanine transaminase and aspartate transaminase, neither clinical signs nor enzyme activity were specific for diagnosis of hepatic neoplasia in the cats of this study.

Adenoma, Bile Duct↗
PubMed1992

Leiomyosarcoma in dogs: 44 cases (1983-1988).

During a 5-year period, leiomyosarcoma was diagnosed in 57 dogs. Forty-four dogs were included in the study on the basis of completeness of medical records. All dogs underwent exploratory laparotomy, and dogs were allotted to 4 groups according to primary site of tumor: spleen (16 dogs, median age 10.3 years), stomach/small intestine (13 dogs, median age 10.3 years), cecum (10 dogs, median age 11.8 years), and liver (5 dogs, median age 9 years). All dogs with leiomyosarcoma of the liver had visible metastasis and were euthanatized at surgery. In the other 3 groups, 79% of the dogs had no gross evidence of metastasis at surgery, and 64% survived greater than 2 weeks. Median survival in these 3 groups was 10 months (range, 1 month to 7 years); 48% died of metastasis, 32% died of unrelated causes, and 16% died of unknown causes. The prognosis in dogs with leiomyosarcoma of the spleen, stomach, small intestine, and especially the cecum is good to excellent if surgery is performed. In dogs with leiomyosarcoma of the liver, the prognosis is poor.

Animals↗
PubMed1992

Pancreatic adenocarcinoma with metastasis in two ferrets.

Exocrine pancreatic adenocarcinoma with carcinomatosis was diagnosed in 2 ferrets. Clinical signs included abdominal distention and hind limb weakness. Ultrasonography revealed moderate ascites in both ferrets, an irregular abdominal mass in 1 ferret, and multiple abdominal masses in the other ferret. The ferrets were euthanatized, and necropsy of 1 ferret revealed carcinomatosis without visceral metastasis.

Adenocarcinoma↗
PubMed1992

A morphologic and immunocytochemical study of hepatic neoplasms in cats.

A retrospective study was done of 47 neoplasms of the hepatic and biliary systems from 47 cats brought to The Animal Medical Center over a period of 10 years (1980 to 1989). Histologic examination of specimens taken at necropsy revealed that 87% (41/47) of the hepatic neoplasms were epithelial and 13% (6/47) were nonepithelial. Of the epithelial tumors, 25/47 (53%) were of intrahepatic bile duct origin, 9/47 (19%) were of hepatocellular origin, 5/47 (11%) involved the extrahepatic bile ducts, and 2/47 (4%) were adenocarcinomas of the gall bladder. Of the nonepithelial neoplasms, hemangiosarcomas were more common, 5/47 (11%), than leiomyosarcomas, 1/47 (2%). Multiple liver lobes were involved in 21/34 (62%) of the epithelial and all six of the nonepithelial intrahepatic neoplasms. Most of the bile duct adenocarcinomas (6/9) were predominantly characterized by acinar structures with mucin production, diffuse necrosis, and little desmoplasia. The hepatocellular carcinomas were characterized by three patterns-trabecular (five tumors), pseudoglandular pattern (two tumors), and anaplastic (one tumor). The hepatic carcinoid was characterized by various-sized groups of acinar and rosettelike structures, some with lumens, separated by thin fibrovascular stroma. The extrahepatic bile duct adenocarcinomas (4/4) were acinopapillary with moderate desmosplasia, whereas the adenocarcinomas of the gall bladder had elongated tubular structures lined by anaplastic cells and a severe desmoplastic reaction. The neuroendocrine carcinoma of the extrahepatic bile duct, the hemangiosarcomas, and the leiomyosarcoma had morphologic features characteristic of these neoplasms. Two of the 16 (13%) bile duct adenomas had anaplastic and precancerous changes. Residual benign components were seen in 10/15 (67%) of the biliary adenocarcinomas, 4/9 (44%) of the intrahepatic bile duct adenocarcinomas, and all of the extrahepatic bile duct adenocarcinomas and gall bladder adenocarcinomas. Results of immunohistochemical studies of the biliary neoplasms were similar to those described in studies of biliary neoplasms in human beings. Results of this study revealed that the frequency of different types of hepatic neoplasms in cats varied from that seen in dogs and human beings, but the morphologic features were comparable.

Animals↗
PubMed1991

Gross, histologic, cytochemical, and immunocytochemical study of medullary thyroid carcinoma in sixteen dogs.

The gross, histomorphologic, cytochemical, and immunocytochemical findings in 16 dogs with medullary thyroid carcinoma were evaluated. Grossly, the neoplasms were encapsulated, firm, lobulated, and grey-white to tan. The typical histologic pattern was groups or sheets of round to polygonal cells with fibrovascular stroma, which was thickened and hyalinized in places. Variants of clear cell (two dogs), giant cell (one dog), and oxyphil cell (one dog) types were also seen. In all 16 dogs, Grimelius-stained sections of the neoplasms revealed intracytoplasmic silver granules; ten tumors contained amyloid and four contained mucin. Immunohistochemically, the neoplasms reacted to AE1/AE3 (n = 13), S-100 protein (n = 5), neuron specific enolase (n = 14), synaptophysin (n = 11), calcitonin (n = 16), somatostatin (n = 4), gastrin (n = 7), and serotonin (n = 6). Only one neoplasm was positive for vimentin. None of the neoplasms reacted to antibodies for neurofilaments, thyroglobulin, insulin, glucagon, or adrenocorticotrophic hormone. Eleven neoplasms contained multiple (two to four) peptides, in various combinations. It was concluded that in dogs, gross and histologic features can be used to distinguish medullary thyroid carcinoma from other thyroid malignancies. Cytochemical and immunocytochemical studies with neuron specific enolase, synaptophysin, and calcitonin can be used to establish the diagnosis of medullary thyroid carcinoma in dogs.

Animals↗
PubMed1990

Lymphomas in dogs. A morphologic, immunologic, and clinical study.

One hundred seventy-six canine lymphomas were classified morphologically using four of the major human lymphoma classification schemes (Rappaport, Lukes-Collins, Kiel, and the Working Formulation). All 176 dogs received the same chemotherapeutic protocol. Sixty-two of these lymphomas had their immunophenotypes established by examination of cell surface markers by automated cytofluorography. Several different morphologic types of canine lymphoma were identified and these were comparable to morphologic categories in human classification schemes. Follicular and low grade lymphomas were rare. The two most common morphologic types were diffuse large cell (centroblastic) and immunoblastic. The Kiel classification appeared to be the most useful human scheme for classifying the canine lymphomas. Cytofluorographic analysis was generally straightforward, and 60 of the 62 lymphomas were placed into one of three immunophenotypic categories: 27 pan-T(LQ1)+SIg+, 21 pan-T(LQ1)-SIg+, and 12 pan-T(LQ1)+SIg-. Two of the lymphomas could not be characterized immunologically because a pre-existing or reactive non-neoplastic population of lymphocytes made interpretation of single cell suspension analysis difficult. The authors identified correlations between morphology and survival and disease-free remission; dogs with high-grade tumors generally survived the longest and had the longest remissions. No correlations were identified between high concentrations of serum lactate dehydrogenase, age, sex, or stage of disease, and morphology, immunophenotype, remission, or survival times. A significant correlation between clinical illness and survival time was documented. The median age of the dogs was nine years, no significant effect of sex on prevalence was observed, and some breeds were significantly overrepresented. Significant morphologic-immunophenotypic correlations included shorter remission and survival times for T-cell tumors than B-cell tumors, and a highly significant correlation between the pan-T(LQ1)+SIg-"T cell" phenotype and hypercalcemia.

Animals↗
PubMed1990

Extra-adrenal pheochromocytoma (paraganglioma) in a cat.

Extra-adrenal pheochromocytoma (paraganglioma) arising from periadrenal tissue was diagnosed in an 18-year-old spayed domestic shorthair cat. The tumor was palpable on physical examination, but not apparent on plain radiographs. The cat developed temporary cardiac arrhythmia while the mass was being handled during excision, suggesting that the tumor was functional. The tumor was characterized histologically by nests and sheets of neoplastic cells separated by thin, vascular stroma. The cells had abundant eosinophilic granular cytoplasm and prominent nuclei. Diffuse, dark, intracytoplasmic granules were seen in sections stained with Grimelius stain. Ultrastructurally, the cells contained round and oblong, membrane-limited, dense core neurosecretory-type granules. Serotonin was detected in the cytoplasm of the neoplastic cells by use of immunocytochemical analysis.

Adrenal Gland Neoplasms↗
PubMed1990

Canine extraskeletal osteosarcoma and chondrosarcoma: a clinicopathologic study of 14 cases.

Canine extraskeletal osteosarcomas are extremely rare tumors. Over a period of 25 years at the Animal Medical Center, approximately 1,000 cases of skeletal osteosarcomas have been diagnosed. During the same period 11 cases of extraskeletal osteosarcomas and three extraskeletal chondrosarcomas were diagnosed. Tumors of the mammary gland were excluded. Extraskeletal osteosarcomas were found in the adrenal gland, eye, gastric ligament, ileum, kidney, liver, spleen, testicle, and vagina. The chondrosarcomas were found in the mitral valves, lungs, and omentum. The mean age of the dogs with extraskeletal osteosarcoma was 11 years, and the mean age of the dogs with extraskeletal chondrosarcoma was 14 years. The The sizes of the tumors ranged from 3 cubic centimeters to 8,315 cubic centimeters. Osteoblastic osteosarcomas were the most common histologic type (7/11, 63.6%); there was a single case of each of the following: fibroblastic, fibrous histiocytic, chondroblastic, and mixed osteo-chondroblastic osteosarcoma. Two of the dogs with chondrosarcomas had mesenchymal chondrosarcomas involving the lungs and omentum. The remaining dog had a regular chondrosarcoma involving the mitral valve. Distant metastases were present in seven of 11 dogs with extraskeletal osteosarcoma and in none of the dogs with chondrosarcoma. In contrast to human beings, in which most extraskeletal osteosarcomas occur in the soft tissues and the extremities, most canine extraskeletal osteosarcomas develop in the visceral organs.

Animals↗
PubMed1989

Argyrophilic, intracellular bacteria in some cats with idiopathic peripheral lymphadenopathy.

Lymph node biopsy specimens from several previously reported cases of unusual feline peripheral lymphadenopathies were re-examined by a modified Dieterlé silver-impregnation staining technique. In a proportion of these specimens, the Dieterlé stain revealed tiny pleomorphic, intensely argyrophilic coccobacilli. These organisms were predominantly located within macrophages. The infected cells were focally distributed, particularly in the interfollicular regions of the nodes. They were inconspicuous in sections stained by other, more conventional staining methods. It is possible that these coccobacilli represent yet another, previously unidentified, cause of chronic lymph node hyperplasia in the cat.

Animals↗
PubMed1989

Cutaneous plasmacytomas in dogs: a morphologic and immunohistochemical study.

Forty-nine cutaneous plasmacytomas in 46 dogs were studied. Tumors occurred at solitary sites in middle-aged to old dogs (mean age, 9.7 years) and most commonly involved the skin of the digits, lips, and ears. Initial diagnosis was made on the basis of light microscopic morphologic findings. Tumors were graded according to the extent of cellular differentiation and immunoreactivity to a panel of immunohistochemical markers (cytokeratins, canine IgG F[ab]2, neurofilament, neuron-specific enolase, S-100 protein, and vimentin). Immunoreactivity was limited to antibodies directed at canine IgG F(ab)2 and vimentin. Vimentin immunoreactivity was usually greater than that of canine IgG F(ab)2, but there was no correlation between immunoreactivity and histologic grade of the tumors. Thirty-six of 39 dogs (92.3%) followed (mean follow-up, 13 months) were cured by surgical excision. The results of this study indicate that canine cutaneous plasmacytomas are benign neoplasms that should be included in the differential diagnosis of cutaneous round cell tumors in dogs.

Animals↗