CASE REPORTS

Some Heterotopic Tissue Remnants in Domestic Animals A. BUNDZA AND T.W. DUKES*

Introduction The terms ectopia, choristoma, aberrant rest or heterotopic and displaced tissue have been applied to microscopically normal tissue in abnormal locations (8). There are some reports of heterotopic tissue available in the literature. The testis has been found in the femoral canal, perineal region or close to the penis (6). Todd reported seven cases of multiple heterotopic testicular tissue in pigs over an eight year period (9). Jolly described epithelial inclusions in the heart of a calf (3). Ectopic spleen has occurred in the scrotum (5), thoracic cavity (7) and pelvic cavity (2) of man and in the pancreas of monkey (4). An ectopic adrenal cortex in the lung of a newborn child was recorded by Bozic (1). Small masses of pancreatic tissue are commonly found in the submucosal connective tissue of the stomach, duodenum and small intestine (8). The purpose of this report is to make our colleagues in the field aware of the occasional occurrence of ectopic tissue remnants in domestic animals which may be mistaken for neoplasia. Reports of Cases Case I - Tissues were taken from a seven month old pig in a slaughterhouse. On postmortem examination the carcass was in good condition. Twenty nodules ranging from 2-10 mm in diameter were found in the liver within 5 cm of the portal lymph node. An hepatic adenoma was suspected. Microscopically, the nodules consisted of encapsulated testicular tissue containing many cross sections of oval and elongated seminiferous tubules. (Figure 1). These tubules were lined by one or two layers of Sertoli cells and an occasional tubule contained a few spermatogonia. Vacuoles were seen in the tubules but no spermatozoa were observed. Case 2a and b - On postmortem examination of a

bovine fetus which was aborted at the seventh month of gestation, there was firm grey-white tissue 5 mm in diameter in the myocardium of the left ventricle extending to the epicardium. In a second animal, a two week old female Holstein calf, a grey-white area measuring 4 x 5 mm was found under the epicardium of the heart. The calf had died suddenly with a history of repeated

bloating. Histological examination of the affected myocardium in both cases revealed numerous duct-like structures of various irregular sizes and shapes lined by a single layer of epithelioid cells (Figures 2 and 3). These glandular structures were separated by variable amounts of fibrous tissue. The ductlike structures in the myocardium of the calf tended to be oval and occasionally round: whereas in the fetus they were elongated and irregular. In both cases these structures resembled glandular remnants.

Case 3 - A one year old female cat was presented for examination with a history of dullness and listlessness for two days. The cat was alert and bright but had a temperature of 1060F. Several

FIGL;RE 1. Encapsulated testicular tissue with convoluted seminiferous tubules and abundance of Leydig cells. In some tubules a few large dark spermatogonia are present in addition to Sertoli cells. Compressed hepatic sinusoids. upper left part. H & E. x150.

*Animal Pathology Division, Health of Animals Branch, Agriculture Box 11300, Station H, Ottawa, Ontario, Canada K2H 8P9.

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FIGURE 3. Highermagnification of gland-likestructures lined with cuboidal epithelioid cells in the myocardium of the calf. Fibrous connective tissue stroma is evident, case 2b. H & E. x380.

FIGURE 2. Duct-like or glandular structures lined by epithelioid cells, in myocardium of bovine fetus of case 2a. H & E. x150.

months after treatment with antibiotics the owner requested the animal be euthanized. Two red nodules were found in the enlarged pancreas. Histological examination of the pancreas revealed an area composed of blood filled sinuses, trabecular remnants and two lymphoid follicles, which were identified as ectopic splenic tissue.

Case 4 - A Persian cat was presented for ovariohysterectomy. A small mass was noted in the ovarian ligament. Microscopically the mass was composed of large cells with abundant cytoplasm and small hyperchromatic nuclei resembling adrenal cortical tissue.

Discussion According to Todd (9) the origin and development of displaced tissue is not known, but is considered to arise from primordial germ cells as they migrate posteriorly in the embryo. Tissue from the pig liver in this report as well as the submissions reported by Todd (9) were suspected neoplasms on gross examination. Displaced tissue is a rare occurrence in domestic animals, however its incidence is not known. Heart inclusions in cattle may not be as rare as suspected. These have

been seen not infrequently during necropsies (T.W. Dukes, unpublished data). These remnants were considered of entodermal origin. White nodules in the liver are frequently encountered during necropsy and at slaughter. These have histologically consisted of lymphoid tissue and in one case was a well developed lymph node. An ectopic lung in the throat of a calf has been seen at necropsy also. These latter cases were not available for reexamination and inclusion in this report. Heterotopic rests of cells almost never give rise to neoplasia (8), although they are commonly mistaken for it.

Sunimarv Multiple ectopic testicular tissue in the liver of a pig is reported. Epithelial inclusions associated with the myocardium of two calves and displaced spleen and adrenal cortex in two cats are described grossly and microscopically. Small nodules of tissue are not infrequently encountered at slaughter. Although these resemble neoplasia, normal but ectopic tissue should also be considered during postmortem examinations.

Risun7e Les auteurs rapportent la presence de plusieurs nodules de tissu testiculaire ectopique, dans le foie d'un porc, ainsi que celle de tissu epithelial, dans le myocarde de deux veaux. Ils decrivent les aspects macroscopique et microscopique de tissu spl&e nique et de cortex surrenalien ectopiques, chez deux chats. On decouvre souvent des petits nodules tissulaires, lors de l'abattage; meme s'ils ressemblent a des neoplasmes, il faut se rappeler qu'ils peuvent correspondre a du tissu normal ectopique. 323

References 1. BOZIC. C. Ectopic fetal adrenal cortex in the lung of a newborn. Virchows Arch. A (Path. Anat. Hist.) 363: 371-374. 1974. 2. HARTFIELD. P.M.. M.E. CLOUSE and B. CADY. Ectopic pelvic spleen. Archs Surg. 3: 603-605. 1976. 3. JOLIY. R.D. Epithelial inclusions of a bovine heart. Can. J. comp. Med. 29: 232-233. 1965. 4. LALU. D.T.L. Ectopic splenic nodules in the pancreas of a capuchin monkey (Cebus albifrons). J. med. Primatol. 2: 67-70. 1973. 5. MAY. J.E. and C.W. BORNE. Ectopic spleen in the scrotum. Report of two cases. J. Urol. 3: 120-123. 1974.

6. NIEBERLE K. and P. COHRS. Textbook of Special Pathologic Anatomy of Domestic Animals. p. 796. Oxford: Pergamon Press. 1967.

LETTER TO THE EDITOR

Over the past twelve months we have had a chance to use both Ovaban and Ovarid at a dosage varying from 2.5 mg daily to a maintenance dose of 2.5 mg twice weekly or 5 mg once weekly on 20 neutered cats with miliary eczema and have had excellent response. We were able to control the condition at a dosage level that was most economical. The most positive aspect of the whole thing was that the ever present fear of iatrogenically creating diabetes with steroids was reduced. We were able to use it in cats that had only been able to be controlled by injections of reposital steroid every four to six weeks and this could have been going on for five to six years. We had one cat 18 years old that had had 31 injections of repositol steroid between 1972 and 1976. Three cats on megestrol therapy became diabetic after starting the drug. Two of them returned to normal after a short course of insulin and cessation of the megestrol. One cat died of ketoacidosis because of delay by the owner in reporting the symptoms. It was concluded that certain cats are very sensitive to this drug and as soon as response is noticed the dosage should be rapidly reduced. Megestrol was used successfully in two cats with rodent ulcers.

Progestogen Therapy for Certain Skin Diseases of Cats DEAR SIR:

There have been two excellent articles in the veterinary literature lately about the use of megestrol acetate in skin problems in cats. See "The response to progestogen treatments of some diseases in cats" by C.J. Chesney (The Journal of Small Animal Practice, Volume 17, No. I, January 1976) and "Treatment of feline miliary dermatitis with megestrol acetate" by J.W. Houdeshell, P.W. Hennessey and H. B. Bigbee (Veterinary Medicine and small Animal Clinician, Pet Practice, April 1977). Both of the above articles refer to the use of Ovarid (Glaxo) and Ovaban (Schering) in the treatment of various skin diseases in cats of a recurring or chronic nature that heretofore had been able to be controlled by the use of long acting steroids (depomedrol-Upjohn). With a letter of permission from the Health Protection Branch of Health and Welfare, Canada it is possible to order this drug from England (Glaxo). I have had no luck at all in ordering it from the Schering company in the U.S.A.

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7. PISKACKOVA. s. Ectopic endothoracic spleen. Stud. Pneumol. Phtiseol. 33: 697-699. 1973.

8. ROBINS. S.L. Pathologic Basis of the Disease. p. 567. Philadelphia, London, Toronto: W.B. Saunders Co., 1974. 9. TODD. G.C.. L.W. NELSON and G. MIGAKI. Multiple heterotopic testicular tissue in the pig. A report of seven cases. Cornell Vet. 58: 614-619. 1968.

J.A. HUTCHISON, D.V.M.

1814 Bank Street Ottawa, Ontario K! V 7 Y6

Some heterotopic tissue remnants in domestic animals.

CASE REPORTS Some Heterotopic Tissue Remnants in Domestic Animals A. BUNDZA AND T.W. DUKES* Introduction The terms ectopia, choristoma, aberrant res...
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