Adenocarcinoma is a type of cancer in horses that originates in the glandular epithelial tissue, affecting various organs such as the lungs, colon, pancreas, and breast. These malignancies are characterized by their ability to form gland-like structures and produce mucin, which can impact tumor behavior and prognosis. This page compiles peer-reviewed research studies and scholarly articles that examine the cellular mechanisms, diagnostic markers, treatment strategies, and clinical outcomes associated with adenocarcinoma in horses, providing insights into its pathogenesis and advances in targeted therapies.
Recknagel S, Nicke M, Schusser GF.To evaluate the diagnostic value of peritoneal fluid (PF) cytology for clinical diagnosis of abdominal neoplasia in horses. Methods: Ten horses with histopathologically confirmed abdominal neoplasia, in which a PF analysis was performed, were included in this retrospective study. PF was analyzed for total protein concentration and a nucleated cell count was performed. Using cytological criteria of malignancy, the PF samples were evaluated regarding their probability of malignancy. Results: Cytologic classification of cells according to criteria of malignancy allowed a positive cytologic diagno...
Mathes RL, Paige Carmichael K, Peroni J, Anthony Moore P.A 5-year-old Draft Horse gelding presented for evaluation of a large, fleshy, ulcerated third eyelid mass OD of 3 weeks duration. Complete ophthalmic examination, ocular ultrasound and skull radiographs revealed a large soft-tissue mass involving the entire third eyelid OD and extending into the ventral right orbit to the level of the globe equator. No other abnormalities were noted on physical or ophthalmic examination. Surgical removal via exenteration was performed 3 months after initial presentation. A lacrimal adenocarcinoma of the third eyelid was diagnosed based on histopathology. Concu...
Taylor SD, Haldorson GJ, Vaughan B, Pusterla N.Gastric neoplasia of horses is incompletely described. Objective: Provide history, clinical signs, and clinicopathological and pathological findings associated with gastric neoplasia in horses. Methods: Twenty-four horses with gastric neoplasia. Methods: Retrospective study. History, clinical signs, and clinicopathological and pathologic findings in horses diagnosed histologically with gastric neoplasia were reviewed. Results: Horses ranged in age from 9 to 25 years (median 18 years at presentation). There was no apparent breed or sex predisposition. The most common presenting complaints were ...
Hewes CA, Sullins KE.To determine outcome for equids with cutaneous neoplasms treated with cisplatin-containing biodegradable beads, alone or in conjunction with debulking. Methods: Retrospective case series. Methods: 56 horses, 1 zebra, 1 donkey, and 1 mule. Methods: Medical records were reviewed. Follow-up information was obtained through telephone conversations with owners and trainers of the animals. Results: 22 tumors were sarcoids, 6 were fibrosarcomas, 1 was a fibroma, 2 were peripheral nerve sheath tumors, 11 were squamous cell carcinomas, 14 were melanomas (13 gray horses and 1 bay horse), 1 was a lymphos...
Roy MF, Parente EJ, Donaldson MT, Habecker P, Axon J.Malignant neoplasia of the equine large colon is rare and reports
are limited to a few cases of adenocarcinoma (Traub et al. 1983;
Wright and Edwards 1984; Rottman et al. 1991; Kirchhof et al.
1996; East et al. 1998) and lymphosarcoma (Dabareiner et al.
1996). Early diagnosis of colonic neoplasia is crucial if one is to
attempt surgical resection before metastasis has occurred.
Unfortunately, microscopic (Dabareiner et al. 1996) or
macroscopic (Traub et al. 1983; Rottman et al. 1991; East et al.
1998) metastasis are often already present by the time of diagnosis
since clinical signs o...
Spoormakers TJ, IJzer J, Sloet van Oldruitenborgh-Oosterbaan MM.A 22-year-old Dutch Warmblood mare was referred to Utrecht University with progressive left hind limb paresis and hyporeflexia. The preliminary clinical diagnosis was the neurological form of equine herpes virus (EHV-1) infection. Within 1 day of admission, the mare became recumbent and deteriorated rapidly. Postmortem examination revealed an adenocarcinoma of the caecum, with metastases in all regional lymph nodes and extending from the lumbar nodes into the vertebral canal, causing spinal cord compression and destruction of the left 4th and 5th lumbar nerves.
Harvey-Micay J.An 8-year-old, Thoroughbred-cross mare presented with recurrent colic. Exploratory laparotomy revealed a large mass near the right dorsal colon; white, raised foci on the liver; and enlarged mesenteric lymph nodes. Cytological examination of biopsies revealed neoplastic cells. The diagnosis of adenocarcinoma was confirmed by histological examination.
Head KW, Dixon PM.The normal gross and histological anatomy of the equine nasal and paranasal sinuses are reviewed and the relationships between the local anatomy, the occurrence of different tumour types, and of tumour spread are examined. The histological classification of the more common equine sinonasal tumours and tumour-like lesions are discussed. Clinical and pathological descriptions of 50 more recently recorded such tumours are separately tabulated. The literature shows that equine sinonasal tumours, both endemic and sporadic, are relatively uncommon in horses, with non-neoplastic growths such as maxil...
Singh SP, Besner GE, Schauer GM.This report describes the clinical and histologic features of a pulmonary tumor in a 14-year-old girl that is most consistent with a rare entity described in the literature as "pulmonary endodermal tumor resembling fetal lung" (PET). This tumor is composed of glycogen-rich columnar cells forming complex glands with focal festooning and mitotic activity, admixed with solid "morules" of cells with eosinophilic cytoplasm and focal nuclear clearing. Patchy tumor necrosis and a bland stroma were also present. Immunoreactivity for carcinoembryonic antigen (CEA), alpha 1-antichymotrypsin, and 12E7 wa...
Reppas GP, McClintock SA, Canfield PJ, Watson GF.Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma. Complementary immunohistochemical studies were made of both fresh and formalin-fixed tumour tissue, and attempts were made to assess the steroid receptor status of fresh tissue biochemically to assess the possibility of ho...
Dalefield RR, Palmer DN.Thyroid tumours have been described as "moderately common" in horses, but diseases associated with them are rare and the actual incidence has not been reported. A survey of thyroids from 29 horses aged 12 to 32 years revealed gross lesions in 11 animals, all older than 17. Most lesions were microfollicular adenomas. There was no evidence that the horses suffered from long-standing iodine deficiency or diffuse hyperplasia. Adenomas were more common than hyperplastic nodules and it is unlikely that the former arose from the latter. One thyroid adenocarcinoma was discovered. Progression from thyr...
Sweeney CR, Gillette DM.Thirty-two horses and 3 ponies had neoplasia involving the thoracic cavity. Lymphosarcoma of the thorax was found in 19 (54.2%) of the equids. The other 16 equids had metastatic adenocarcinoma (7 horses; 20%), metastatic squamous cell carcinoma (5 equids; 14.3%), metastatic hemangiosarcoma (3 equids; 8.6%) or undifferentiated sarcoma (1 horse; 2.9%). Thoracic neoplasia was diagnosed before death in 15 equids (42.9%).
Owen RA, Haywood S, Kelly DF.A four-year-old shire mare with haematuria, colic, terminal weight loss and an abdominal mass had a large unilateral renal adenocarcinoma. Clinical signs were monitored for 11 months. Increased serum copper concentrations were measured on two occasions. Hypercupraemia is discussed as a possible paraneoplastic change.
Reynolds BL, Stedham MA, Lawrence JM, Heltsley JR.A space-occupying intracranial mass was diagnosed in a horse. The clinical findings included blindness, circling to the right, apprehension, anorexia, weight loss, and leaning against the stall. On ophthalmoscopic examination, the most striking observation was complete bilateral devascularization of the retinas. The horse was euthanatized and necropsied. Necroscopy revealed the mass to occupy the olfactory and frontal areas of the left hemisphere of the brain and part of the left frontal sinus. Microscopically, the mass was an adenocarcinoma and probably arose from the lining epithelium of the...
Head KW, Dixon PM.The normal gross and histological anatomy of the equine nasal and paranasal sinuses are reviewed and the relationships between the local anatomy, the occurrence of different tumour types, and of tumour spread are examined. The histological classification of the more common equine sinonasal tumours and tumour-like lesions are discussed. Clinical and pathological descriptions of 50 more recently recorded such tumours are separately tabulated. The literature shows that equine sinonasal tumours, both endemic and sporadic, are relatively uncommon in horses, with non-neoplastic growths such as maxil...
Taylor SD, Haldorson GJ, Vaughan B, Pusterla N.Gastric neoplasia of horses is incompletely described. Objective: Provide history, clinical signs, and clinicopathological and pathological findings associated with gastric neoplasia in horses. Methods: Twenty-four horses with gastric neoplasia. Methods: Retrospective study. History, clinical signs, and clinicopathological and pathologic findings in horses diagnosed histologically with gastric neoplasia were reviewed. Results: Horses ranged in age from 9 to 25 years (median 18 years at presentation). There was no apparent breed or sex predisposition. The most common presenting complaints were ...
Reppas GP, McClintock SA, Canfield PJ, Watson GF.Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma. Complementary immunohistochemical studies were made of both fresh and formalin-fixed tumour tissue, and attempts were made to assess the steroid receptor status of fresh tissue biochemically to assess the possibility of ho...
Harvey-Micay J.An 8-year-old, Thoroughbred-cross mare presented with recurrent colic. Exploratory laparotomy revealed a large mass near the right dorsal colon; white, raised foci on the liver; and enlarged mesenteric lymph nodes. Cytological examination of biopsies revealed neoplastic cells. The diagnosis of adenocarcinoma was confirmed by histological examination.
Dalefield RR, Palmer DN.Thyroid tumours have been described as "moderately common" in horses, but diseases associated with them are rare and the actual incidence has not been reported. A survey of thyroids from 29 horses aged 12 to 32 years revealed gross lesions in 11 animals, all older than 17. Most lesions were microfollicular adenomas. There was no evidence that the horses suffered from long-standing iodine deficiency or diffuse hyperplasia. Adenomas were more common than hyperplastic nodules and it is unlikely that the former arose from the latter. One thyroid adenocarcinoma was discovered. Progression from thyr...
Recknagel S, Nicke M, Schusser GF.To evaluate the diagnostic value of peritoneal fluid (PF) cytology for clinical diagnosis of abdominal neoplasia in horses. Methods: Ten horses with histopathologically confirmed abdominal neoplasia, in which a PF analysis was performed, were included in this retrospective study. PF was analyzed for total protein concentration and a nucleated cell count was performed. Using cytological criteria of malignancy, the PF samples were evaluated regarding their probability of malignancy. Results: Cytologic classification of cells according to criteria of malignancy allowed a positive cytologic diagno...
Roy MF, Parente EJ, Donaldson MT, Habecker P, Axon J.Malignant neoplasia of the equine large colon is rare and reports
are limited to a few cases of adenocarcinoma (Traub et al. 1983;
Wright and Edwards 1984; Rottman et al. 1991; Kirchhof et al.
1996; East et al. 1998) and lymphosarcoma (Dabareiner et al.
1996). Early diagnosis of colonic neoplasia is crucial if one is to
attempt surgical resection before metastasis has occurred.
Unfortunately, microscopic (Dabareiner et al. 1996) or
macroscopic (Traub et al. 1983; Rottman et al. 1991; East et al.
1998) metastasis are often already present by the time of diagnosis
since clinical signs o...
Reynolds BL, Stedham MA, Lawrence JM, Heltsley JR.A space-occupying intracranial mass was diagnosed in a horse. The clinical findings included blindness, circling to the right, apprehension, anorexia, weight loss, and leaning against the stall. On ophthalmoscopic examination, the most striking observation was complete bilateral devascularization of the retinas. The horse was euthanatized and necropsied. Necroscopy revealed the mass to occupy the olfactory and frontal areas of the left hemisphere of the brain and part of the left frontal sinus. Microscopically, the mass was an adenocarcinoma and probably arose from the lining epithelium of the...
Owen RA, Haywood S, Kelly DF.A four-year-old shire mare with haematuria, colic, terminal weight loss and an abdominal mass had a large unilateral renal adenocarcinoma. Clinical signs were monitored for 11 months. Increased serum copper concentrations were measured on two occasions. Hypercupraemia is discussed as a possible paraneoplastic change.
Spoormakers TJ, IJzer J, Sloet van Oldruitenborgh-Oosterbaan MM.A 22-year-old Dutch Warmblood mare was referred to Utrecht University with progressive left hind limb paresis and hyporeflexia. The preliminary clinical diagnosis was the neurological form of equine herpes virus (EHV-1) infection. Within 1 day of admission, the mare became recumbent and deteriorated rapidly. Postmortem examination revealed an adenocarcinoma of the caecum, with metastases in all regional lymph nodes and extending from the lumbar nodes into the vertebral canal, causing spinal cord compression and destruction of the left 4th and 5th lumbar nerves.
Hewes CA, Sullins KE.To determine outcome for equids with cutaneous neoplasms treated with cisplatin-containing biodegradable beads, alone or in conjunction with debulking. Methods: Retrospective case series. Methods: 56 horses, 1 zebra, 1 donkey, and 1 mule. Methods: Medical records were reviewed. Follow-up information was obtained through telephone conversations with owners and trainers of the animals. Results: 22 tumors were sarcoids, 6 were fibrosarcomas, 1 was a fibroma, 2 were peripheral nerve sheath tumors, 11 were squamous cell carcinomas, 14 were melanomas (13 gray horses and 1 bay horse), 1 was a lymphos...
Sweeney CR, Gillette DM.Thirty-two horses and 3 ponies had neoplasia involving the thoracic cavity. Lymphosarcoma of the thorax was found in 19 (54.2%) of the equids. The other 16 equids had metastatic adenocarcinoma (7 horses; 20%), metastatic squamous cell carcinoma (5 equids; 14.3%), metastatic hemangiosarcoma (3 equids; 8.6%) or undifferentiated sarcoma (1 horse; 2.9%). Thoracic neoplasia was diagnosed before death in 15 equids (42.9%).
Mathes RL, Paige Carmichael K, Peroni J, Anthony Moore P.A 5-year-old Draft Horse gelding presented for evaluation of a large, fleshy, ulcerated third eyelid mass OD of 3 weeks duration. Complete ophthalmic examination, ocular ultrasound and skull radiographs revealed a large soft-tissue mass involving the entire third eyelid OD and extending into the ventral right orbit to the level of the globe equator. No other abnormalities were noted on physical or ophthalmic examination. Surgical removal via exenteration was performed 3 months after initial presentation. A lacrimal adenocarcinoma of the third eyelid was diagnosed based on histopathology. Concu...
Singh SP, Besner GE, Schauer GM.This report describes the clinical and histologic features of a pulmonary tumor in a 14-year-old girl that is most consistent with a rare entity described in the literature as "pulmonary endodermal tumor resembling fetal lung" (PET). This tumor is composed of glycogen-rich columnar cells forming complex glands with focal festooning and mitotic activity, admixed with solid "morules" of cells with eosinophilic cytoplasm and focal nuclear clearing. Patchy tumor necrosis and a bland stroma were also present. Immunoreactivity for carcinoembryonic antigen (CEA), alpha 1-antichymotrypsin, and 12E7 wa...
