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Tumours and pseudotumours in some reptiles
,I. (:osw.
PATH.
TUklOURS
1976. 1.01.. 86.
AND
337
PSEUDOTUMOURS
IN
SOME
REPTILES
BY E. ELKAN De,ixzrtmentof Histopathology, Mount Vernon Hospital. .,vorthwood,3fiddlesex
J. E.
COOPER
Clinical Re.rearchCentre, W&ford Road, Hurrou~, hlidcilesex
INTRODCCtTIOK
There is a paucity of data on neoplastic conditions of reptiles. A recent revie\\ on spontaneous neoplasms in reptiles by Billups and Harshbarger (in press; lists 10 papers on lizards and 41 papers on snakes, suggesting that, while neoplasms are rare in lower vertebrates generally, they are particularly so in lizards. Probably the most common reptilian neoplasm is the epidermal papilloma (Heller, 1948; Koch, 1904; Elkan and Reichenbach-Klinke, 1974). ‘These tumours are probably of viral origin and often arise in response to damage by cctoparasites. ?\lescnchymal neoplasms in lizards are particularly rare. Apart from an enchondroma seen by Bland Sutton (1885) and a case of osteomata reported by Stolk ( 1958)) only two casesof malignant lymphomatosis have been recorded (Zwart and Harshbarger, 1972). A typical mesenchymosarcoma has not, so far, been reported in lizards. In this paper we report three neoplastic tumours in reptiles and a number of cases of granulomatous pseudotumours. The word c“tumour” is used in its original sense of swelling i.e. the appearance of a mass of tissue in an area where it would not normally occur. Such tumours may be of inflammatory or of neoplastic origin. Since the word tumour is nowadays frequently used to denote neoplasia, the non-neoplastic swellings may be described as “pseudoturnours”. MATERIALS
AND
METHODS
l’hree speciesof reptile were investigated. Lacerta sicula Raf., the “ruin”
or ‘imeadow” lizard, is a species common to Italy. of these lizards has been maintained since 1958 at the Department of Zoology of the University of Tel Aviv (Director Prof. Dr H. Mendelssohn). In the summer of 1974 several casualties occurred in this collection and it was noticed that all the dead lizards had prominent local deformities of one kind or another. Seven specimens were received for investigation, some alive, some preserved in formaldehyde, together with three healthy control specimens. Gjclura cornuta Cope is a Caribbean iguana commonly called the rhinoceros iguana. A specimen kept by a British herpetologist was brought to the Department because it had developed a large gular swelling over a period of 3 months.
Spain and Dalmatia. A colony
338
E.
ELKAN
AND
J. E.
COOPER
The third reptile was a specimen of the South American snake Boa constrictor. This was also kept by a British herpetologist, having been purchased from a dealer. After initially feeding normally on rodents, the snake began to show signsof lack of tonus, imbalance and inability to climb. Eventually it refusedfood, became moribund with convulsive movements and died. It was then received for post-mortem examination. Clinical techniques are described in the Results. Tissues were examined bacteriologically, histologically and histochemically. Culture was carried out on standard bacteriological media. Tissues were fixed in 10 per cent. formalin, decalcified where necessary, double embedded and sectioned at 5 to 8 pm. Staining methods used were HE., van Gieson, Alcian Blue-H E., Phosphotungstic Acid-haematoxylin (P.T.A.H.), Gram, Ziebl-Neelsen and MayGriinwald Giemsa stain. RESULTS
The results are divided into four headings: I. Pseudotumoursin Lacerta sicula RaJ: Naked eye inspection of 6 lizards showed in each case gross deformity in some part of the body, but the lesions were not identical in any two of the lizards. The lesions consisted of gross swellings which were solid and firmly attached to the substratum. They were found in the gular (Fig. l), thoracic and abdominal regions. The abdominal lesions, which, in some casesoccupied all the available space and displaced the intestines, were always part of, or attached to, the liver (Fig. 2). In some casesthe whole liver was riddled with white foci of 3-5 mm. diameter.
Fig.
1. Lucertu
sicula. Gular
granuloma.
Histological investigation of these 6 lizards showed identical lesions. None of the growths could be described as “tumours” sensu stricto, but all were inflammatory granulomata of bacterial origin. Each mass, whether large or small, was surrounded by a fibrous capsule. Beneath this there was a zone of
TUMOURS
AND
PSEUDOTUMOURS
33!1
IN REPTILES
small-cell infiltration with some eosinophil leucocytes. Towards the centrc this zone changed into a solid mass of necrotic tissue in which no definite structures could be identified. Gram positive and Gram negative bacteria were present. Only Proteus mirabilis could be recovered from the cultures. A search for ac-idfast bacilli and fungi proved negative.
Fig.
II.
2. Lacerta sicula. Hepatic
granulomata
B gular pseudotumour in Cyclura
cornuta
displacing
the main
viscera.
Cope
This animal had a discrete swelling, approximately 3 x2 cm., on the lefi side of the gular region, overlying the left mandibular ramus. The swelling was firm and apparently painless but it showed slight fluctuation on pressurr~. .A similar but considerably smaller swelling was found on the distal joint of digit 11 on the right forefoot. Aspiration from the gular lesion was attcmptt~d under local analgesia. No aspirate could be obtained but the tip of the n~dlc yielded ~1growth of’ an Enterobacter species. The gular lesion was excised surgically and was found to consist of ;L “Marc” of yellow, apparently laminated caseous material of 2.2 cm. diamrtcr surrounded by a fibrous, vascular capsule. Surgery of the digital lesion rr.sultccl in the removal of two shiny caseous nodules (0.45 and 0.35 cm. diamctcr) one on each side of the phalanx. Histological examination of the gular lesion confirmed the laminatc~d appearance. The nodule was composed almost entirely of acellular, necrotic debris but there was a thin peripheral cellular layer beneath the fibrous capsule. In the case of the digital nodules the substance appeared similar hut the cellular layer was thicker and included eosinophil leucocytcs. Small separate nodules which were identical histologically were found in sections of the skin overlying the gular tumour. In addition to the Enterobacter sp. obtained
340
E.
ELKAN
AND
J. E.
COOPER
from the gular region, Escherichia coli and Sta@ylococcus epidermidis were isolated from the digital lesion. No acid-fast bacteria or fungi were found. The lesions in the iguana were similar to those seen in the lizards, particularly one specimen where the lesion also occupied the gular region. Clinically the lesions had appeared as “turnours”; histologically however they proved to be granulomatous pseudotumours. III.
A mesenchymosarcoma in Lacerta
The seventh of the series of from the other six. The lizard, a The left foreleg was transformed long x 15 mm. wide x 12 mm. be normal and it accepted food
Fig.
3.
sicula Raf.
lizards received from Tel Aviv was different fully grown female, measured 14 cm. in length. into a large swelling which measured 22 mm. deep (Fig. 3). Otherwise the lizard seemed to and water on arrival.
Lacerta siculu. Tumour
of the
left
foreleg.
The swelling was solid and a radiograph revealed no visible involvement of the brachial skeleton. Small foci of calcification could be seen in the peripheral part of the swelling. The shadow cast by the tumour extended to the left half of the thoracic cavity, displacing the lungs to the right. The skin was stretched but intact over the whole area and there was no ulceration, but the surface of the peripheral lateral part appeared “lumpy” as if in this area the growth was in the process of splitting up into smaller separate entities. While the lizard seemed otherwise normal it was kept under optimal conditions in a vivarium and fed with mealworms. To ascertain whether the foreleg lesion was identical to those seen in the previous six specimens a needle biopsy was carried out. It was noted that, on being punctured, this tumour bled more freely than expected whereas sections of the granulomata in the other 6 lizards had shown no capillaries.
TUMOURS
AND
PSEUDOTUMOURS
IN
341
REPTILES
Smears made from the biopsy material showed many groups of densely staining round or oval nuclei with no visible cytoplasm, resembling “oat-cells”. This tumour, obviously, was not a granuloma. Culture of the aspirate yielded Bacillus subtilis, Haemophilus catanhnlis, Sarcina spp. and diphtheroids. No acid-fast bacilli or fungi were isolated. The lizard survived the biopsy but it became increasingly sluggish and began to refuse food and water. When it was obvious that it would not recover and that no treatment was likely to have any effect, it was killed with chloroform. Immediately after death a transverse cut was made through the thoracic~ rrgion including the foreleg and the tumour (Figs 4 and 5), part of which wxs set aside for histochemical investigation for enzymes.
Fig.
Fig.
J. Larerfa sicuk. Transverse mveloping the thorax.
5. Lacer&z sicula. Diagram the thorax.
section
through
to Fig. 4. C. thoracic
the hrachial
cavity;
tumour
S, sarcoma,
and the
enveloping
thorax.
S. sarcoma.
and penetrating
342
E. ELKAN
AND
J. E. COOPER
Histological examination showed that the main mass of the brachial tumour surrounded the humerus, radius and ulna down to the metacarpus. Proximally the tumour extended subcutaneously dorsally and ventrally so as to envelop the thorax as far as the mid-line. The central part of the neoplasm penetrated the thoracic cavity through intercostal gaps, extending to the mediastinum and the mesenterium, involving the dorsal aorta, the stomach and the lungs (Fig. 6). On the side of the breakthrough the peritoneum was replaced by a
Fig.
6. Lacerfu siculu. Mesenchymosarcoma
invading
the lung.
L, lung;
N, neoplasm.
thick sheet of neoplastic tissue. The skin covering the tumour, though much stretched, was intact throughout, but only the epidermis could be identified, the dermis being replaced by neoplastic tissue which had not breached the epidermis anywhere. The brachial muscle fibres were thinned out and separated from each other by neoplastic tissue (Fig. 7). A few melanophores in the superficial layer of the tumour may have been remnants of the dermis. The cytology of the tumour was complex. Spindle cells with elongated Some of them were bi- or trinucleate and in almost nuclei predominated. every field there were clusters of the “oat-cell” type of cells already seen in the biopsy material. In the radio-ulnar region there was, in many fields, no clear delineation between bone and soft tissue. No clear periosteal layer could be identified in these areas; the bone appeared eroded, suggesting that the tumour might have originated from the periosteum. The tumour was well vascularized. In one instance a vascular space was seen with new capillaries growing out into the lumen (Fig. 8). Serial sections revealed one small necrotic focus which may have been a remnant of the biopsy puncture. Staining with Alcian Blue produced a positive result in the peripheral part of the tumour only. In this region the cellular structure was much less dense than in the central parts of the tumour. The fibrous structure here was that of a loose mesh of thin fibres enclosing nests of large vacuolated cells, some of
TUMOURS
AND
PSEUDOTUMOURS
343
1N REPTILES
whil ch had up to seven nuclei. None of these cells, however, resembled the corn .monly seen types of giant cells. No mitotic figures were seen. The gent Era1 No pict me in the peripheral part of the tumour was that of a myxosarcoma. cart ilaginous tissue could be identified. extensions of the tumour was ident ical T ‘he histology of the intrathoracic growth, spindle cells predominating. The ao irtic wit1 r that of the primary
Fig.
7. Lacerta sicula. Relation N, neoplasm.
Fig.
of brachial
8. Lacerta sic&.
sarcoma
Vascular
to periosteum
space with
and bone.
neoplastic
B, bone; I;, muscle
capillaries.
fi bres :
344
E. ELKAN
AND
J. E. COOPER
adventitia, the pleuro-peritoneum and the lungs were penetrated by neoplastic tissue. No secondary deposits of the tumour were found in any other part of the body. The heart was normal. Endothelial cells in the blood vessels of the tumour were positive for acid phosphatase and for non-specific esterase but the tumour cells themselves proved negative. The acid phosphatase was stable on treatment with tartaric acid. Staining for chloroacetate esterase was negative. On the strength of these findings the tumour was classified as a mesenchymosarcoma. IV.
Malignant
tumaurs and complex pathology in a Boa constrictor
Post-mortem examination of this specimen, which measured 136 cm. in length, showed that while the anal passage was patent, the intestines were enveloped in recent adhesions. The stomach and small intestine were contracted and empty. An ileal intussusception involving 1.5 cm. of gut was found above the ileo-caecal junction. The large intestine was distended and filled to capacity with faecal matter. There were no intestinal parasites. Two tumours were found among the adhesions in the mesenterium, neither of them in continuity with the intestinal canal. The smaller tumour-measured O-5 ~0.5 x O-5 cm., the large 2 x2 xl cm. The heart showed a cream-coloured, round, well defined tumour near the base measuring O-5 x0.5 cm. There was no sign gland was moderately of atheromatosis of the large vessels. The thyroid enlarged (length 0.17 cm., width 0.6 cm.) cream and brown mottled in colour. There was considerable tissue damage in the vicinity of the lung rendering macroscopical interpretation difficult. Due to insufficient fixation the mucous membrane of the ileum and colon
Fig.
9. Boo constrictor.
Mesenteric
adenocarcinoma.
TUMOURS
AND
PSEUDOTUMOURS
IN
345
REPTILES
showed some degree of autolysis histologically but the gastric mucosa was in good condition. In sections through the area of the intussusception some prominent lymphatic plaques were present at the base of the mucosa, but there was nothing, histologically, to explain the intussusception.
Fig.
10. Boa constrictor.
Fig.
Cervical
1 I. Boa constriclor.
metastasis
Cardiac
of mesenteric
rhabdomyosarcoma
adenocarcinoma.
in situ.
The smaller of the two mesenteric tumours proved to be a conglomeration of hyperplastic lymphatic tissue. The larger was a well differentiated adenocarcinoma (Fig. 9) made up of strands of alveolar epithelium embedded in a meshwork of fine collagenous fibres. The tumour was of uniform structure
346
E. ELKAN
AND
J. E. COOPER
throughout and was well vascularized. A small deposit, almost identical in structure, was found microscopically close to the thyroid gland (Fig. 10). The cardiac tumour was situated in the external layer of the myocardium (Fig. 11). P.T.A.H. stained sections showed numerous cross-striated fibres in the neoplastic tissue (Fig. 12) and many mitotic figures, most of them abnormal, could be seen, sometimes up to three in one field. The tumour was well vascularized but, although it displaced the adjacent myocardium, it did not infiltrate it and the heart as a whole was not distorted by the tumour (Fig. 11). The liver showed severe fatty infiltration but no metastases of any of the primary tumours. The fat-body was well preserved and histologically normal.
Fig.
12. Boa constrictor.
Cardiac
sarcoma.
Striated
fibres.
The lung, apart from a massive haemorrhage in the cervical region, appeared histologically normal. The ovaries were immature. The follicular tissue of the thyroid gland, which normally resembles that of other vertebrates, was almost totally replaced by dense lymphocytic infiltration. Normal follicles could not be located but small interspersed droplets of colloid remained embedded in the massive lymphocytic infiltration. The blood vessels were heavily congested. The general picture was that of lymphocytic (lymphoid) thyroiditis. DISCUSSION
In this paper attention has been drawn to the significance in reptiles of infectious granulomata as differential diagnoses of neoplastic tumours. The two types of lesion appear very similar clinically and histopathology may be necessary for a clear distinction. It may be significant that the granulomata described occurred mostly, but not invariably, along the intestinal canal or in the liver which may suggest oral infection. The reptiles possibly feed on carriers of pathogens ( ? cockroaches)
TUMOURS
AND
PSEUDOTUMOURS
IN
347
REPTILES
or they may injure the mucous membrane of the mouth or the oesophagus while swallowing splintered bones. Kratzer (1974) describes a grass snake (jVatrix n&x schweizeri) which was found with the skull of a captured lizard firmly wedged between its jaws and this supports the observation that reptiles often try to swallow prey beyond their capacity. The various bacteria so f%r recovered from these cases could all be accidental commensals and allow no firm conclusion as to the nature of the pathogen responsible for the granulomatn. Clinically all these cases look similar and the fact that in the iguana an additional lesion appeared in a digit suggests that dispersion by the blood or the lymph stream may occur. At the same time, however, these animals did not die of septicaemia and all the pseudotumours took several weeks to develop. The malignant tumours described appear to be rarities, but they reinforce the suspicion that, given time, many of the neoplasms known from mammals may bc recognized in reptiles. What was remarkable in the case of the Hotr constrictor was the occurrence of two such tumours, both malignant brat of entirely different histological structure, in one snake. The cause of death in this case is also of interest. Neither the cardiac sarcoma nor the mesenteric carcinoma was sufficiently large to kill the snake although either might have done so eventually. The lymphocytic thyroiditis may have been allied to the lymphocytic hyperplasia seen in the intestine. It was severe and there was practically no normal thyroidal tissue left, but it was an unlikcl) cause of death in a fully grown snake. Other possible causes of death were thr massive cervical haemorrhage or the ileal intussusception. The cause of the* haemorrhage could not be ascertained. It was not due to trauma but it ma) have impeded the movement of the heart which was already weakened b) the tumour at its base. The ileal intussusception caused a complete intestinal obstruction; but paradoxically it was the proximal part of the intestine that was empty and the distal part that was distended with faecal matter. The suggestion that this might have been an agonal or a post-mortem condition was ruled out by the abundance of intestinal adhesions. One is left to conclude that the Boa constrictor died as a result of an unusual number of simultaneous pathological conditions. SUMMARY
The following conditions are described : granulomatous pseudotumours found in several specimens of Lacerta sicula Raf. and in the iguana Cyclura corm&a Cope; a mesenchymosarcoma found in Lacerta sicula Raf.; an adenocarcinoma and a rhabdomyosarcoma found in a Boa constrictor Laur. An ileal intussusception and a severe lymphocytic (lymphoid) thyroiditis were incidentally found in the Boa constrictor. The conditions are discussed and attention drawn to the differential diagnosis of reptile tumours. ACKNOWLEDGMENTS
We wish
to thank
Prof. H. Mendelssohn, supplying the material on which this report
Mr
M. C. Eisler
and Mr J. Pickett fol for surgical
is based and Miss M. John
348
E. ELKAN
AND
J, E. COOPER
assistance. We express our gratitude to Dr M. H. Bennett this investigation to be carried out in his department.
for allowing
much
of
REFERENCES
Billups, L. H. and Harshbarger, J. C. (in press). Spontaneous neoplasms in reptiles. In CRC Handbook of Laboratory Animal Science. E. C. Melby and N. H. Altman, Eds. CRC Press Inc., Cleveland, Ohio. Bland-Sutton, J. (1885). T umours in Animals. Journal of Anatomy and Physiology, 19, 415-475. Elkan, E. and Reichenbach-Klinke, H. (1974) Color Atlas of the Diseases of Fish, Amphibians and Reptiles. T.F.H. Publications, Neptune, New Jersey, U.S.A. Heller (1948). Quoted in Schlumberger, H. G. and Luckt, B. Tumours in fishes, amphibians and reptiles. Cancer Research, 8, 657-754. Koch, M. (1904). Demonstration einiger Geschwtilste bei Tieren. Verhandlungcn der Deutschen Gesellschaft fiir Pathologie, 7, 136-l 47. Kratzer, H. (1974). Beobachtungen tiber den Nahrungserwerb bei der Milos Ringelnatter (Matrix natrix schweizeri). Salamandra, 10, 49-54. Stolk, A. (1958). Tumours of Reptiles IV. Multiple osteomas in the lizard Lacerta viridis. Beaufortia, 7, No. 79, l-9. neoplasms in lizards : Zwart, P., and Harshbarger, J. C. (1972). H aematopoietic Report of a typical case in Hydrosaurus amboinensis and of a probable case, in Varanus ralvator. International Journal of Cancer, 9, 548-553. [Received for publication,
May 20th, 19751
PATH.
TUklOURS
1976. 1.01.. 86.
AND
337
PSEUDOTUMOURS
IN
SOME
REPTILES
BY E. ELKAN De,ixzrtmentof Histopathology, Mount Vernon Hospital. .,vorthwood,3fiddlesex
J. E.
COOPER
Clinical Re.rearchCentre, W&ford Road, Hurrou~, hlidcilesex
INTRODCCtTIOK
There is a paucity of data on neoplastic conditions of reptiles. A recent revie\\ on spontaneous neoplasms in reptiles by Billups and Harshbarger (in press; lists 10 papers on lizards and 41 papers on snakes, suggesting that, while neoplasms are rare in lower vertebrates generally, they are particularly so in lizards. Probably the most common reptilian neoplasm is the epidermal papilloma (Heller, 1948; Koch, 1904; Elkan and Reichenbach-Klinke, 1974). ‘These tumours are probably of viral origin and often arise in response to damage by cctoparasites. ?\lescnchymal neoplasms in lizards are particularly rare. Apart from an enchondroma seen by Bland Sutton (1885) and a case of osteomata reported by Stolk ( 1958)) only two casesof malignant lymphomatosis have been recorded (Zwart and Harshbarger, 1972). A typical mesenchymosarcoma has not, so far, been reported in lizards. In this paper we report three neoplastic tumours in reptiles and a number of cases of granulomatous pseudotumours. The word c“tumour” is used in its original sense of swelling i.e. the appearance of a mass of tissue in an area where it would not normally occur. Such tumours may be of inflammatory or of neoplastic origin. Since the word tumour is nowadays frequently used to denote neoplasia, the non-neoplastic swellings may be described as “pseudoturnours”. MATERIALS
AND
METHODS
l’hree speciesof reptile were investigated. Lacerta sicula Raf., the “ruin”
or ‘imeadow” lizard, is a species common to Italy. of these lizards has been maintained since 1958 at the Department of Zoology of the University of Tel Aviv (Director Prof. Dr H. Mendelssohn). In the summer of 1974 several casualties occurred in this collection and it was noticed that all the dead lizards had prominent local deformities of one kind or another. Seven specimens were received for investigation, some alive, some preserved in formaldehyde, together with three healthy control specimens. Gjclura cornuta Cope is a Caribbean iguana commonly called the rhinoceros iguana. A specimen kept by a British herpetologist was brought to the Department because it had developed a large gular swelling over a period of 3 months.
Spain and Dalmatia. A colony
338
E.
ELKAN
AND
J. E.
COOPER
The third reptile was a specimen of the South American snake Boa constrictor. This was also kept by a British herpetologist, having been purchased from a dealer. After initially feeding normally on rodents, the snake began to show signsof lack of tonus, imbalance and inability to climb. Eventually it refusedfood, became moribund with convulsive movements and died. It was then received for post-mortem examination. Clinical techniques are described in the Results. Tissues were examined bacteriologically, histologically and histochemically. Culture was carried out on standard bacteriological media. Tissues were fixed in 10 per cent. formalin, decalcified where necessary, double embedded and sectioned at 5 to 8 pm. Staining methods used were HE., van Gieson, Alcian Blue-H E., Phosphotungstic Acid-haematoxylin (P.T.A.H.), Gram, Ziebl-Neelsen and MayGriinwald Giemsa stain. RESULTS
The results are divided into four headings: I. Pseudotumoursin Lacerta sicula RaJ: Naked eye inspection of 6 lizards showed in each case gross deformity in some part of the body, but the lesions were not identical in any two of the lizards. The lesions consisted of gross swellings which were solid and firmly attached to the substratum. They were found in the gular (Fig. l), thoracic and abdominal regions. The abdominal lesions, which, in some casesoccupied all the available space and displaced the intestines, were always part of, or attached to, the liver (Fig. 2). In some casesthe whole liver was riddled with white foci of 3-5 mm. diameter.
Fig.
1. Lucertu
sicula. Gular
granuloma.
Histological investigation of these 6 lizards showed identical lesions. None of the growths could be described as “tumours” sensu stricto, but all were inflammatory granulomata of bacterial origin. Each mass, whether large or small, was surrounded by a fibrous capsule. Beneath this there was a zone of
TUMOURS
AND
PSEUDOTUMOURS
33!1
IN REPTILES
small-cell infiltration with some eosinophil leucocytes. Towards the centrc this zone changed into a solid mass of necrotic tissue in which no definite structures could be identified. Gram positive and Gram negative bacteria were present. Only Proteus mirabilis could be recovered from the cultures. A search for ac-idfast bacilli and fungi proved negative.
Fig.
II.
2. Lacerta sicula. Hepatic
granulomata
B gular pseudotumour in Cyclura
cornuta
displacing
the main
viscera.
Cope
This animal had a discrete swelling, approximately 3 x2 cm., on the lefi side of the gular region, overlying the left mandibular ramus. The swelling was firm and apparently painless but it showed slight fluctuation on pressurr~. .A similar but considerably smaller swelling was found on the distal joint of digit 11 on the right forefoot. Aspiration from the gular lesion was attcmptt~d under local analgesia. No aspirate could be obtained but the tip of the n~dlc yielded ~1growth of’ an Enterobacter species. The gular lesion was excised surgically and was found to consist of ;L “Marc” of yellow, apparently laminated caseous material of 2.2 cm. diamrtcr surrounded by a fibrous, vascular capsule. Surgery of the digital lesion rr.sultccl in the removal of two shiny caseous nodules (0.45 and 0.35 cm. diamctcr) one on each side of the phalanx. Histological examination of the gular lesion confirmed the laminatc~d appearance. The nodule was composed almost entirely of acellular, necrotic debris but there was a thin peripheral cellular layer beneath the fibrous capsule. In the case of the digital nodules the substance appeared similar hut the cellular layer was thicker and included eosinophil leucocytcs. Small separate nodules which were identical histologically were found in sections of the skin overlying the gular tumour. In addition to the Enterobacter sp. obtained
340
E.
ELKAN
AND
J. E.
COOPER
from the gular region, Escherichia coli and Sta@ylococcus epidermidis were isolated from the digital lesion. No acid-fast bacteria or fungi were found. The lesions in the iguana were similar to those seen in the lizards, particularly one specimen where the lesion also occupied the gular region. Clinically the lesions had appeared as “turnours”; histologically however they proved to be granulomatous pseudotumours. III.
A mesenchymosarcoma in Lacerta
The seventh of the series of from the other six. The lizard, a The left foreleg was transformed long x 15 mm. wide x 12 mm. be normal and it accepted food
Fig.
3.
sicula Raf.
lizards received from Tel Aviv was different fully grown female, measured 14 cm. in length. into a large swelling which measured 22 mm. deep (Fig. 3). Otherwise the lizard seemed to and water on arrival.
Lacerta siculu. Tumour
of the
left
foreleg.
The swelling was solid and a radiograph revealed no visible involvement of the brachial skeleton. Small foci of calcification could be seen in the peripheral part of the swelling. The shadow cast by the tumour extended to the left half of the thoracic cavity, displacing the lungs to the right. The skin was stretched but intact over the whole area and there was no ulceration, but the surface of the peripheral lateral part appeared “lumpy” as if in this area the growth was in the process of splitting up into smaller separate entities. While the lizard seemed otherwise normal it was kept under optimal conditions in a vivarium and fed with mealworms. To ascertain whether the foreleg lesion was identical to those seen in the previous six specimens a needle biopsy was carried out. It was noted that, on being punctured, this tumour bled more freely than expected whereas sections of the granulomata in the other 6 lizards had shown no capillaries.
TUMOURS
AND
PSEUDOTUMOURS
IN
341
REPTILES
Smears made from the biopsy material showed many groups of densely staining round or oval nuclei with no visible cytoplasm, resembling “oat-cells”. This tumour, obviously, was not a granuloma. Culture of the aspirate yielded Bacillus subtilis, Haemophilus catanhnlis, Sarcina spp. and diphtheroids. No acid-fast bacilli or fungi were isolated. The lizard survived the biopsy but it became increasingly sluggish and began to refuse food and water. When it was obvious that it would not recover and that no treatment was likely to have any effect, it was killed with chloroform. Immediately after death a transverse cut was made through the thoracic~ rrgion including the foreleg and the tumour (Figs 4 and 5), part of which wxs set aside for histochemical investigation for enzymes.
Fig.
Fig.
J. Larerfa sicuk. Transverse mveloping the thorax.
5. Lacer&z sicula. Diagram the thorax.
section
through
to Fig. 4. C. thoracic
the hrachial
cavity;
tumour
S, sarcoma,
and the
enveloping
thorax.
S. sarcoma.
and penetrating
342
E. ELKAN
AND
J. E. COOPER
Histological examination showed that the main mass of the brachial tumour surrounded the humerus, radius and ulna down to the metacarpus. Proximally the tumour extended subcutaneously dorsally and ventrally so as to envelop the thorax as far as the mid-line. The central part of the neoplasm penetrated the thoracic cavity through intercostal gaps, extending to the mediastinum and the mesenterium, involving the dorsal aorta, the stomach and the lungs (Fig. 6). On the side of the breakthrough the peritoneum was replaced by a
Fig.
6. Lacerfu siculu. Mesenchymosarcoma
invading
the lung.
L, lung;
N, neoplasm.
thick sheet of neoplastic tissue. The skin covering the tumour, though much stretched, was intact throughout, but only the epidermis could be identified, the dermis being replaced by neoplastic tissue which had not breached the epidermis anywhere. The brachial muscle fibres were thinned out and separated from each other by neoplastic tissue (Fig. 7). A few melanophores in the superficial layer of the tumour may have been remnants of the dermis. The cytology of the tumour was complex. Spindle cells with elongated Some of them were bi- or trinucleate and in almost nuclei predominated. every field there were clusters of the “oat-cell” type of cells already seen in the biopsy material. In the radio-ulnar region there was, in many fields, no clear delineation between bone and soft tissue. No clear periosteal layer could be identified in these areas; the bone appeared eroded, suggesting that the tumour might have originated from the periosteum. The tumour was well vascularized. In one instance a vascular space was seen with new capillaries growing out into the lumen (Fig. 8). Serial sections revealed one small necrotic focus which may have been a remnant of the biopsy puncture. Staining with Alcian Blue produced a positive result in the peripheral part of the tumour only. In this region the cellular structure was much less dense than in the central parts of the tumour. The fibrous structure here was that of a loose mesh of thin fibres enclosing nests of large vacuolated cells, some of
TUMOURS
AND
PSEUDOTUMOURS
343
1N REPTILES
whil ch had up to seven nuclei. None of these cells, however, resembled the corn .monly seen types of giant cells. No mitotic figures were seen. The gent Era1 No pict me in the peripheral part of the tumour was that of a myxosarcoma. cart ilaginous tissue could be identified. extensions of the tumour was ident ical T ‘he histology of the intrathoracic growth, spindle cells predominating. The ao irtic wit1 r that of the primary
Fig.
7. Lacerta sicula. Relation N, neoplasm.
Fig.
of brachial
8. Lacerta sic&.
sarcoma
Vascular
to periosteum
space with
and bone.
neoplastic
B, bone; I;, muscle
capillaries.
fi bres :
344
E. ELKAN
AND
J. E. COOPER
adventitia, the pleuro-peritoneum and the lungs were penetrated by neoplastic tissue. No secondary deposits of the tumour were found in any other part of the body. The heart was normal. Endothelial cells in the blood vessels of the tumour were positive for acid phosphatase and for non-specific esterase but the tumour cells themselves proved negative. The acid phosphatase was stable on treatment with tartaric acid. Staining for chloroacetate esterase was negative. On the strength of these findings the tumour was classified as a mesenchymosarcoma. IV.
Malignant
tumaurs and complex pathology in a Boa constrictor
Post-mortem examination of this specimen, which measured 136 cm. in length, showed that while the anal passage was patent, the intestines were enveloped in recent adhesions. The stomach and small intestine were contracted and empty. An ileal intussusception involving 1.5 cm. of gut was found above the ileo-caecal junction. The large intestine was distended and filled to capacity with faecal matter. There were no intestinal parasites. Two tumours were found among the adhesions in the mesenterium, neither of them in continuity with the intestinal canal. The smaller tumour-measured O-5 ~0.5 x O-5 cm., the large 2 x2 xl cm. The heart showed a cream-coloured, round, well defined tumour near the base measuring O-5 x0.5 cm. There was no sign gland was moderately of atheromatosis of the large vessels. The thyroid enlarged (length 0.17 cm., width 0.6 cm.) cream and brown mottled in colour. There was considerable tissue damage in the vicinity of the lung rendering macroscopical interpretation difficult. Due to insufficient fixation the mucous membrane of the ileum and colon
Fig.
9. Boo constrictor.
Mesenteric
adenocarcinoma.
TUMOURS
AND
PSEUDOTUMOURS
IN
345
REPTILES
showed some degree of autolysis histologically but the gastric mucosa was in good condition. In sections through the area of the intussusception some prominent lymphatic plaques were present at the base of the mucosa, but there was nothing, histologically, to explain the intussusception.
Fig.
10. Boa constrictor.
Fig.
Cervical
1 I. Boa constriclor.
metastasis
Cardiac
of mesenteric
rhabdomyosarcoma
adenocarcinoma.
in situ.
The smaller of the two mesenteric tumours proved to be a conglomeration of hyperplastic lymphatic tissue. The larger was a well differentiated adenocarcinoma (Fig. 9) made up of strands of alveolar epithelium embedded in a meshwork of fine collagenous fibres. The tumour was of uniform structure
346
E. ELKAN
AND
J. E. COOPER
throughout and was well vascularized. A small deposit, almost identical in structure, was found microscopically close to the thyroid gland (Fig. 10). The cardiac tumour was situated in the external layer of the myocardium (Fig. 11). P.T.A.H. stained sections showed numerous cross-striated fibres in the neoplastic tissue (Fig. 12) and many mitotic figures, most of them abnormal, could be seen, sometimes up to three in one field. The tumour was well vascularized but, although it displaced the adjacent myocardium, it did not infiltrate it and the heart as a whole was not distorted by the tumour (Fig. 11). The liver showed severe fatty infiltration but no metastases of any of the primary tumours. The fat-body was well preserved and histologically normal.
Fig.
12. Boa constrictor.
Cardiac
sarcoma.
Striated
fibres.
The lung, apart from a massive haemorrhage in the cervical region, appeared histologically normal. The ovaries were immature. The follicular tissue of the thyroid gland, which normally resembles that of other vertebrates, was almost totally replaced by dense lymphocytic infiltration. Normal follicles could not be located but small interspersed droplets of colloid remained embedded in the massive lymphocytic infiltration. The blood vessels were heavily congested. The general picture was that of lymphocytic (lymphoid) thyroiditis. DISCUSSION
In this paper attention has been drawn to the significance in reptiles of infectious granulomata as differential diagnoses of neoplastic tumours. The two types of lesion appear very similar clinically and histopathology may be necessary for a clear distinction. It may be significant that the granulomata described occurred mostly, but not invariably, along the intestinal canal or in the liver which may suggest oral infection. The reptiles possibly feed on carriers of pathogens ( ? cockroaches)
TUMOURS
AND
PSEUDOTUMOURS
IN
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REPTILES
or they may injure the mucous membrane of the mouth or the oesophagus while swallowing splintered bones. Kratzer (1974) describes a grass snake (jVatrix n&x schweizeri) which was found with the skull of a captured lizard firmly wedged between its jaws and this supports the observation that reptiles often try to swallow prey beyond their capacity. The various bacteria so f%r recovered from these cases could all be accidental commensals and allow no firm conclusion as to the nature of the pathogen responsible for the granulomatn. Clinically all these cases look similar and the fact that in the iguana an additional lesion appeared in a digit suggests that dispersion by the blood or the lymph stream may occur. At the same time, however, these animals did not die of septicaemia and all the pseudotumours took several weeks to develop. The malignant tumours described appear to be rarities, but they reinforce the suspicion that, given time, many of the neoplasms known from mammals may bc recognized in reptiles. What was remarkable in the case of the Hotr constrictor was the occurrence of two such tumours, both malignant brat of entirely different histological structure, in one snake. The cause of death in this case is also of interest. Neither the cardiac sarcoma nor the mesenteric carcinoma was sufficiently large to kill the snake although either might have done so eventually. The lymphocytic thyroiditis may have been allied to the lymphocytic hyperplasia seen in the intestine. It was severe and there was practically no normal thyroidal tissue left, but it was an unlikcl) cause of death in a fully grown snake. Other possible causes of death were thr massive cervical haemorrhage or the ileal intussusception. The cause of the* haemorrhage could not be ascertained. It was not due to trauma but it ma) have impeded the movement of the heart which was already weakened b) the tumour at its base. The ileal intussusception caused a complete intestinal obstruction; but paradoxically it was the proximal part of the intestine that was empty and the distal part that was distended with faecal matter. The suggestion that this might have been an agonal or a post-mortem condition was ruled out by the abundance of intestinal adhesions. One is left to conclude that the Boa constrictor died as a result of an unusual number of simultaneous pathological conditions. SUMMARY
The following conditions are described : granulomatous pseudotumours found in several specimens of Lacerta sicula Raf. and in the iguana Cyclura corm&a Cope; a mesenchymosarcoma found in Lacerta sicula Raf.; an adenocarcinoma and a rhabdomyosarcoma found in a Boa constrictor Laur. An ileal intussusception and a severe lymphocytic (lymphoid) thyroiditis were incidentally found in the Boa constrictor. The conditions are discussed and attention drawn to the differential diagnosis of reptile tumours. ACKNOWLEDGMENTS
We wish
to thank
Prof. H. Mendelssohn, supplying the material on which this report
Mr
M. C. Eisler
and Mr J. Pickett fol for surgical
is based and Miss M. John
348
E. ELKAN
AND
J, E. COOPER
assistance. We express our gratitude to Dr M. H. Bennett this investigation to be carried out in his department.
for allowing
much
of
REFERENCES
Billups, L. H. and Harshbarger, J. C. (in press). Spontaneous neoplasms in reptiles. In CRC Handbook of Laboratory Animal Science. E. C. Melby and N. H. Altman, Eds. CRC Press Inc., Cleveland, Ohio. Bland-Sutton, J. (1885). T umours in Animals. Journal of Anatomy and Physiology, 19, 415-475. Elkan, E. and Reichenbach-Klinke, H. (1974) Color Atlas of the Diseases of Fish, Amphibians and Reptiles. T.F.H. Publications, Neptune, New Jersey, U.S.A. Heller (1948). Quoted in Schlumberger, H. G. and Luckt, B. Tumours in fishes, amphibians and reptiles. Cancer Research, 8, 657-754. Koch, M. (1904). Demonstration einiger Geschwtilste bei Tieren. Verhandlungcn der Deutschen Gesellschaft fiir Pathologie, 7, 136-l 47. Kratzer, H. (1974). Beobachtungen tiber den Nahrungserwerb bei der Milos Ringelnatter (Matrix natrix schweizeri). Salamandra, 10, 49-54. Stolk, A. (1958). Tumours of Reptiles IV. Multiple osteomas in the lizard Lacerta viridis. Beaufortia, 7, No. 79, l-9. neoplasms in lizards : Zwart, P., and Harshbarger, J. C. (1972). H aematopoietic Report of a typical case in Hydrosaurus amboinensis and of a probable case, in Varanus ralvator. International Journal of Cancer, 9, 548-553. [Received for publication,
May 20th, 19751