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Identification of two cases of bovine undifferentiated tumours (squamous cell carcinoma and adenocarcinoma) by electron microscopy
J. COMP.PATH. 1985.VOL. 95
SHORT
PAPERS
IDENTIFICATION OF TWO CASES OF BOVINE UNDIFFERENTIATED TUMOURS (SQUAMOUS CELL CARCINOMA AND ADENOCARCINOMA) BY ELECTRON MICROSCOPY BY
K. KADOTA, T. NEI, Third ResearchDivision, National Institute of Animal Health, I-l, K annondai 3-chome, ratabe-machi, Tmkuba-gun, Ibaraki, 305 Japan
H. NIZEKI Chuo Livestock Hygiene Service Center, Tamagata, Japan
and
M. KITA Nanbu Livestock Hygiene Sewice Center, Ishikawa, Japan
INTRODUCTION
Microscopic identification of a tumour depends on recognition of the type of or cells composing it (Schneider, 1978). When cells are well differentiated primary foci are obvious, identification is usually easy. When cells are highly anaplastic and primary foci are missed, cellular identification may be difficult by light microscopy. In such cases, carcinomas are often termed simple carcinoma or undifferentiated carcinoma, while sarcomas are termed round cell sarcoma, spindle cell sarcoma or the like. These designations may include not only true anaplastic tumours but also act as waste baskets. Much more highly anaplastic tumours are difficult to identify even as sarcomas or carcinomas. We encountered 2 cases of bovine tumours which were diflicult to diagnose definitely by light microscopy. Ultrastructural examination, however, gave an accurate diagnosis-undifferentiated adenocarcinoma of the lung and undifferentiated squamous cell carcinoma. The ultrastructure of these neoplasms in cattle has not been reported. MATERIALS
AND
METHODS
In one case (Cow 1)) a tumour was detected in a 1O-year-old Japanese Black cow. An induration of 10 cm in diameter was found on the left side of the body and spreading oedema gradually appeared around it. Finally the cow was killed because of swelling of the whole of the left half of the body. In the other case (Cow 2), a tumour was detected in a 2.5-year-old Holstein cow which had been killed because of debility. Tissues were fixed in 10 per cent formalin, processed routinely, and sections were 002 l-9975/85/020291 + 04 $03.00/O
0 1985Academic PressIX. (London) Limited
292
K.
KADOTA
et d.
stained with haematoxylin and eosin (HE), periodic acid-Schiff, and silver stain by Watanabe’s method. Formalin-fixed tissues were also utilized for electron microscopic examination. After initial fixation, the tissues were post-fixed in 1 per cent osmium tetroxide and treated routinely.
RESULTS
AND
DISCUSSION
In Cow 1, the iliac and renal lymph nodes were extremely enlarged. Grayish white tumour tissue was found in the lumbar subcutis and psoas, although there was no change in the skin surface. Large nodes were recognized in the adipose capsule and connective tissues near the ovaries. In the grossly detected parts neoplastic cells were seen as emboli growing in veins and lymph vessels (Fig. 1). Many expanded thin-walled vessels with emboli existed around relatively large veins, which contained nectoric or organized emboli. The vessels were considered to be collaterals. Disturbance of circulation by emboli may have caused lymphostasis, oedema and necrosis of fat cells. Neoplastic cells had round or oval nuclei and a few nucleoli. The cytoplasm was polygonal and eosinophilic. Although most of the cells had a narrow band of cytoplasm compared with the nuclei, large cells containing much cytoplasm were occasionally seen [Fig. 1 (a)]. F rom the findings mentioned above, it was reasonably to diagnose this tumour as a simple carcinoma; primary foci were not seen. On electron microscopy, the cells had many cytoplasmic projections (Fig. 2) which were observed also by freeze-replication (Fig. 3). Intracellular bridges and tonofilaments were seen (Fig. 4). Free ribosomes were relatively abundant, while cytoplasmic organelles were poor. There were rather few desmosomes and tonofilaments. Accordingly, undifferentiated squamous cell carcinoma was the final diagnosis. The primary site composed of minute infiltrating foci may have existed in the skin of the left side and have been the cause of the clinical findings and distribution of lesions, although squamous cell carcinoma can arise in various organs. In Cow 2, a large mass and enlarged nodules were detected in the lungs. Some nodules were also found in the heart and kidneys. The nuclei were oval to fusiform, and the cytoplasm was polygonal to fusiform (Fig. 5). One or a few nucleoli were found in the cells. Even with silver staining, no sign of carcinomatous
structure
was found.
The
appropriate
diagnosis
was, therefore,
considered to be spindle cell sarcoma or fibrosarcoma. By electron microscopy, desmosomes and basement membrane were and secretory observed (Fig. 6). I n spite of their rarity, some microvilli granules were found. These findings showed that this tumour was an undifferentiated adenocarcinoma of the lung. There have been few papers reporting the ultrastructure of primary lung neoplasms and squamous cell carcinomas in animals (Borland and Webber, 1966; Perk, Hod and Nobel, 197 I; Sanford and Bundza, 1982), and most of the tumours were examined only by light microscopy. Now that neoplasia is becoming even more important in human medicine, ultrastructural study of animal tumours should be done routinely for its value in comparative
medicine.
TUMOUR
Fig. 1. Case 1. Neopiastic x 400. Fig. 2. Neoplastic cytoplasmic
cells inside
IDENTIFICATION
lumen
of blood
cells characterized by irregular projections. X 2970.
BY
vesseir.
nuclear
HE
Fig. 4. Tonofilament-desmosome desmosome. x 11 700. Fig. 5. Case 2. Uniform Fig. 6. Drsmosomes
growth
(arrows)
complex
of neoplastic seen sporadically
(arrow!
made
cells. HE
x 250. Inset
membranes,
Fig. 3. Cy-toplasmic projections between two cells; one has a fracture the other the cut face (upper left). x 5940. up
EM
(a): clear
a few tonofilaments face of the nucleus
of a combination
large cells. HE and numerous
(lower
right)
of tonofilaments
and and
x 250.
and some rough
surfaced
endoplasmic
reticulum.
x 4500.
294
K.
KADOTA
et cd.
SUMMARY
Two cases of undifferentiated tumours were found in cows. Electron microscopy revealed that one was an undifferentiated squamous cell carcinoma of unknown primary site and the other an undifferentiated adenocarcinoma of the lung. ACKNOWLEDGMENTS
We thank Dr S. Ishino,
Messrs M. Ito and Y. Ando for their help with this work. REFERENCES
Borland, R., and Webber, A. J. (1966). An electron microscope study of squamous cell carcinoma in merino sheep associated with keratin-filled cysts of the skin. Cancer Research, 26, 172-182. Perk, K., Hod, I., and Nobel, T. A. (1971). Pulmonary adenomatosis of sheep (Jaagsiekte). I. Ultrastructure of the tumor. Journal of the National Cancer Institute, 46,525-537. Sanford, S. E., and Bundza, A. (1982). Multicentric bronchiole-alveolar neoplasm in a steer. Veterinary Pathology, 19, 95-97. Schneider, R. (1978). General considerations. In Tumors in Domestic Animals, 2nd Edit., J. E. Moulton, Ed. University of California Press, Berkeley and Los Angeles, California, pp. 1-15. [Received for publication, November 24th, 19831
SHORT
PAPERS
IDENTIFICATION OF TWO CASES OF BOVINE UNDIFFERENTIATED TUMOURS (SQUAMOUS CELL CARCINOMA AND ADENOCARCINOMA) BY ELECTRON MICROSCOPY BY
K. KADOTA, T. NEI, Third ResearchDivision, National Institute of Animal Health, I-l, K annondai 3-chome, ratabe-machi, Tmkuba-gun, Ibaraki, 305 Japan
H. NIZEKI Chuo Livestock Hygiene Service Center, Tamagata, Japan
and
M. KITA Nanbu Livestock Hygiene Sewice Center, Ishikawa, Japan
INTRODUCTION
Microscopic identification of a tumour depends on recognition of the type of or cells composing it (Schneider, 1978). When cells are well differentiated primary foci are obvious, identification is usually easy. When cells are highly anaplastic and primary foci are missed, cellular identification may be difficult by light microscopy. In such cases, carcinomas are often termed simple carcinoma or undifferentiated carcinoma, while sarcomas are termed round cell sarcoma, spindle cell sarcoma or the like. These designations may include not only true anaplastic tumours but also act as waste baskets. Much more highly anaplastic tumours are difficult to identify even as sarcomas or carcinomas. We encountered 2 cases of bovine tumours which were diflicult to diagnose definitely by light microscopy. Ultrastructural examination, however, gave an accurate diagnosis-undifferentiated adenocarcinoma of the lung and undifferentiated squamous cell carcinoma. The ultrastructure of these neoplasms in cattle has not been reported. MATERIALS
AND
METHODS
In one case (Cow 1)) a tumour was detected in a 1O-year-old Japanese Black cow. An induration of 10 cm in diameter was found on the left side of the body and spreading oedema gradually appeared around it. Finally the cow was killed because of swelling of the whole of the left half of the body. In the other case (Cow 2), a tumour was detected in a 2.5-year-old Holstein cow which had been killed because of debility. Tissues were fixed in 10 per cent formalin, processed routinely, and sections were 002 l-9975/85/020291 + 04 $03.00/O
0 1985Academic PressIX. (London) Limited
292
K.
KADOTA
et d.
stained with haematoxylin and eosin (HE), periodic acid-Schiff, and silver stain by Watanabe’s method. Formalin-fixed tissues were also utilized for electron microscopic examination. After initial fixation, the tissues were post-fixed in 1 per cent osmium tetroxide and treated routinely.
RESULTS
AND
DISCUSSION
In Cow 1, the iliac and renal lymph nodes were extremely enlarged. Grayish white tumour tissue was found in the lumbar subcutis and psoas, although there was no change in the skin surface. Large nodes were recognized in the adipose capsule and connective tissues near the ovaries. In the grossly detected parts neoplastic cells were seen as emboli growing in veins and lymph vessels (Fig. 1). Many expanded thin-walled vessels with emboli existed around relatively large veins, which contained nectoric or organized emboli. The vessels were considered to be collaterals. Disturbance of circulation by emboli may have caused lymphostasis, oedema and necrosis of fat cells. Neoplastic cells had round or oval nuclei and a few nucleoli. The cytoplasm was polygonal and eosinophilic. Although most of the cells had a narrow band of cytoplasm compared with the nuclei, large cells containing much cytoplasm were occasionally seen [Fig. 1 (a)]. F rom the findings mentioned above, it was reasonably to diagnose this tumour as a simple carcinoma; primary foci were not seen. On electron microscopy, the cells had many cytoplasmic projections (Fig. 2) which were observed also by freeze-replication (Fig. 3). Intracellular bridges and tonofilaments were seen (Fig. 4). Free ribosomes were relatively abundant, while cytoplasmic organelles were poor. There were rather few desmosomes and tonofilaments. Accordingly, undifferentiated squamous cell carcinoma was the final diagnosis. The primary site composed of minute infiltrating foci may have existed in the skin of the left side and have been the cause of the clinical findings and distribution of lesions, although squamous cell carcinoma can arise in various organs. In Cow 2, a large mass and enlarged nodules were detected in the lungs. Some nodules were also found in the heart and kidneys. The nuclei were oval to fusiform, and the cytoplasm was polygonal to fusiform (Fig. 5). One or a few nucleoli were found in the cells. Even with silver staining, no sign of carcinomatous
structure
was found.
The
appropriate
diagnosis
was, therefore,
considered to be spindle cell sarcoma or fibrosarcoma. By electron microscopy, desmosomes and basement membrane were and secretory observed (Fig. 6). I n spite of their rarity, some microvilli granules were found. These findings showed that this tumour was an undifferentiated adenocarcinoma of the lung. There have been few papers reporting the ultrastructure of primary lung neoplasms and squamous cell carcinomas in animals (Borland and Webber, 1966; Perk, Hod and Nobel, 197 I; Sanford and Bundza, 1982), and most of the tumours were examined only by light microscopy. Now that neoplasia is becoming even more important in human medicine, ultrastructural study of animal tumours should be done routinely for its value in comparative
medicine.
TUMOUR
Fig. 1. Case 1. Neopiastic x 400. Fig. 2. Neoplastic cytoplasmic
cells inside
IDENTIFICATION
lumen
of blood
cells characterized by irregular projections. X 2970.
BY
vesseir.
nuclear
HE
Fig. 4. Tonofilament-desmosome desmosome. x 11 700. Fig. 5. Case 2. Uniform Fig. 6. Drsmosomes
growth
(arrows)
complex
of neoplastic seen sporadically
(arrow!
made
cells. HE
x 250. Inset
membranes,
Fig. 3. Cy-toplasmic projections between two cells; one has a fracture the other the cut face (upper left). x 5940. up
EM
(a): clear
a few tonofilaments face of the nucleus
of a combination
large cells. HE and numerous
(lower
right)
of tonofilaments
and and
x 250.
and some rough
surfaced
endoplasmic
reticulum.
x 4500.
294
K.
KADOTA
et cd.
SUMMARY
Two cases of undifferentiated tumours were found in cows. Electron microscopy revealed that one was an undifferentiated squamous cell carcinoma of unknown primary site and the other an undifferentiated adenocarcinoma of the lung. ACKNOWLEDGMENTS
We thank Dr S. Ishino,
Messrs M. Ito and Y. Ando for their help with this work. REFERENCES
Borland, R., and Webber, A. J. (1966). An electron microscope study of squamous cell carcinoma in merino sheep associated with keratin-filled cysts of the skin. Cancer Research, 26, 172-182. Perk, K., Hod, I., and Nobel, T. A. (1971). Pulmonary adenomatosis of sheep (Jaagsiekte). I. Ultrastructure of the tumor. Journal of the National Cancer Institute, 46,525-537. Sanford, S. E., and Bundza, A. (1982). Multicentric bronchiole-alveolar neoplasm in a steer. Veterinary Pathology, 19, 95-97. Schneider, R. (1978). General considerations. In Tumors in Domestic Animals, 2nd Edit., J. E. Moulton, Ed. University of California Press, Berkeley and Los Angeles, California, pp. 1-15. [Received for publication, November 24th, 19831