cutaneous extraskeletal mesenchymal chondrosarcoma in a cat (pages 121–124)

8/9/2019 Cutaneous Extraskeletal Mesenchymal Chondrosarcoma in a Cat (Pages 121–124)

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122 M Romanucci et al.

© 2005 European Society of Veterinary Dermatology, Veterinary Dermatology

, 16

, 121–124

In order to exclude primary production of osteoid

and therefore a diagnosis of extraskeletal osteosar-

coma, Alcian blue staining at pH 1 and 2.5 was per-

formed. This method showed pale blue stained areas of

osteoid, surrounded by contiguous areas of deep blue

stained chondroid matrix, a pattern characteristic of

foci of endochondral ossification.

Further, an immunohistochemical analysis was

performed using a streptavidin-biotin-peroxidase

technique and specific antivimentin (1 : 100, clone V9,

mouse monoclonal, DAKO, Glostrup, Denmark) andanti-S100 protein (1 : 1500, rabbit polyclonal; DAKO)

antibodies (Abs). Antigen retrieval was performed by

heat treating sections in citrate buffer at pH 6 in a

microwave oven for 5 min.

The immunohistochemical results revealed a diffuse

vimentin positivity in both chondroid and undifferen-

tiated cells (Fig. 4), whilst S-100 protein immunoreac-

tivity was detected in most cartilaginous cells with a

cytoplasmic and nuclear distribution. The surrounding

mesenchymal cells were negative (Fig. 5).

DISCUSSION

Mesenchymal chondrosarcoma is an uncommon

variant of chondrosarcoma, typically composed of

two characteristic tumour components: cartilaginous

islands and sheets of primitive mesenchymal cells.

2

It

has been described in dogs

3–6

and humans,

2,7,8

pre-

dominantly young adult patients, both skeletally and

extraskeletally. In dogs, for example, extraskeletal mes-

enchymal chondrosarcoma has been reported in the

lungs, omentum,

6

pericardium

3

and retroperitoneal

space.

5

One case of this tumour has also been reported

in the soft tissues of the cheek pouch of a Chinesehamster

9

and another consisting of undifferentiated

mesenchymal cells, myxoid and chondroid tissue in the

subcutis of the neck in a cow.

10

Figure 4. Feline cutaneous mesenchymal chondrosarcoma.

The cartilaginous component and the spindle cells clearly show

immunohistochemical positivity for vimentin. Streptavidin-

biotin-peroxidase method, Papanicolau’s haematoxylin

counterstaining. Bar = 30 µm.


Coexistence of undifferentiated spindle cells (arrowheads) and

chondroid areas within the neoplastic parenchyma (arrows). H&E.

Bar = 30 µm.

Figure 2. Feline cutaneous mesenchymal chondrosarcoma. Single

chondroid elements with abundant extracellular matrix (arrows).

H&E. Bar = 30 µm.

Figure 3. Feline cutaneous mesenchymal chondrosarcoma. Areas of

endochondral ossification within the chondroid islands. H&E.

Bar = 75 µm.




, 16

, 121–124

Feline mesenchymal chondrosarcoma 123

In our case, histological diagnosis, based on the

biphasic morphological pattern of the tumour, was

confirmed by the immunohistochemical findings,

which are in agreement with those reported in canine

4

and human cases.

2,7

In particular, S-100 protein expres-

sion in the cartilaginous islands is considered to be

most characteristic of this tumour.

7

This protein is

expressed by several cell types such as glia, Schwann

cells, melanocytes, Langherans cells of the epidermis,

histiocytes, myoepithelial cells and others, including

chondrocytes.

11

Furthermore, it has been demonstrated

that only well-differentiated cartilaginous cells have apositive reaction for S-100 protein,

12

which could

represent an important immunohistochemical marker

in the differential diagnosis of chondrosarcoma from

other mesenchymal tumours. However, its expression

can not be used to differentiate mesenchymal chondro-

sarcoma from ordinary chondrosarcoma.

4

Moreover, we performed Alcian staining which is

thought to be useful in making a differential diagnosis

between extraskeletal osteosarcoma and chondrosar-

coma because, unlike chondrosarcoma, the deep-blue-

stained cartilaginous matrix does not surround the

pale-stained osteoid in osteosarcoma.

1,13

To the best of our knowledge, the mesenchymal sub-

type of this tumour has to date not been reported in

the cat, although extraskeletal chondrosarcoma has

been observed in the soft tissues of the extremities.

14

Chondrosarcoma has also been described as a possible

type of feline postvaccinal sarcoma;

15

however, vacci-

nations or other types of inoculation and traumas at

the tumour site had been excluded in the clinical

history of our cat. In addition, the typical histological

aspects of vaccine-associated sarcomas, such as peritu-

moural follicular aggregates of lymphocytes and the

presence of histiocytic cells phagocytosing adjuvant

material,

15

were not observed.Although the giant cells observed in this case are an

unusual feature for mesenchymal chondrosarcomas,

they have been previously described in the literature.

16

In conclusion, although the prognosis for this type

of tumour in humans is poor and there is a high incid-

ence of local recurrence and distant metastases,

2

in the

dog distant metastases are rarely observed

5

and, in our

case, 6 months on from surgical treatment neither

recurrence nor metastases have been detected. In this

respect, surgical excision is without a doubt the treat-ment of choice for mesenchymal chondrosarcoma,

8,17

and complete resectability appears to be an important

prognostic factor.

8

ACKNOWLEDGEMENT

We thank Tania Bastow for the English review of the

manuscript.

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Selective immunoreactivity of the single chondrocytic tumour cells

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124 M Romanucci et al.


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Résumé

Un chat, mâle, âgé de 4 ans, a été présenté pour une masse sous-cutanée adhérente localisée dans la

région lombo-sacrée. L’examen histopathologique a montré un néoplasme bien limité mais non encapsulé, cara-

ctérisé par une prolifération de cellules épineuses, avec un fort degré de mitoses. Entre ces cellules, étaient présentes

des éléments cellulaires avec une différenciation chondroïde. De larges zones de tissu cartilagineux, avec des foyers

d’ossification endochondrale, une nécrose et un tissu myxoïde ont également été identifiés dans le parenchyme

néoplasique. Sur la base de ce patron histopathologique, caractérisé par la coexistence d’ilôts cartilagineux, et

de cellules mésenchymateuses indifférenciées, du résultat d’une coloration par le bleu Alcian à différents pH, d’un

marquage inmunohistochimique contre la vimentine et la protéine S-100, et de l’absence d’atteinte du squelette

et d’autres foyer tumoral primitif, un diagnostic de chondrosarcome mésenchymateux extrasquelettique a été

posé. L’anamnèse ne rapportait pas de traumatisme, de vaccination ou d’autre type d’inoculation sous-cutanée.

Six mois après la chirurgie, aucune récurrence ou métastase n’a été notée.

Resumen

Un gato macho de 4 años presentaba una masa subcutánea fijada a planos profundos, en la región

lumbosacra. El examen histopatológico reveló una neoplasia bien definida pero no encapsulada caracterizada

por una población de células predominantemente fusiformes, con una actividad mitótica elevada. Dispersos entre

estas células se encontraban elementos celulares aislados con diferenciación condroide. También se observaron,

en el parénquima neoplásico, amplias áreas de tejido cartilaginoso con focos de osificación endocondral, necrosis

y tejido mixoide. Basándonos en el patrón histológico, caracterizado por la coexistencia de islas cartilaginosas

y células mesenquimatosas indiferenciadas, en los resultados de las tinciones de azul Alciano en varios pH, la

reactividad inmunohistoquímica contra vimentina y S-100, y la ausencia de implicación esquelética u otras local-

izaciones tumorales primarias, se realizó un diagnóstico de condrosarcoma mesenquimatoso extraesquelético.

La historia clínica del gato excluía traumatismos, vacunaciones u otro tipo de inoculación subcutánea. Seis meses

después del tratamiento quirúrgico, no se habían detectado recidivas ni metástasis.

Zusammenfassung

Eine 4 Jahre alte Katze wurde mit einer festsitzenden subkutanen Masse im Lumbo-

sakralbereich vorgestellt. Die histopathologische Untersuchung zeigte eine scharf umrissene aber nicht verka-

pselte Neoplasie, die durch eine Proliferation von vorrangig Spindelzellen mit hoher mitotischer Aktivität

gekennzeichnet war. Diese Zellen waren mit einzelnen zellulären Elementen mit chondroider Differenzierung

durchsetzt. Im neoplastischen Parenchym wurden auch große Bereiche von knorpeligem Gewebe mit fokaler

enchondraler Ossifikation, Nekrose und myxoidem Gewebe beobachtet. Basierend auf dem histologischem Mus-

ter, das durch die Koexistenz von knorpeligen Inseln und undifferenzierten mesenchymalen Zellen charakterisiert

war, den Resultaten der Alzianblau-Färbung bei verschiedenen pH-Werten, der immunhistochemischen Reak-

tivität gegen Vimentin und S 100 und fehlender Beteiligung von Skelett oder anderen primären Tumorlokalisa-

tionen wurde die Diagnose Chondrosarkom gestellt. Aufgrund des Vorberichtes wurde Trauma Impfungen oder

anderen Arten von subkutaner Inokulation ausgeschlossen. Sechs Monate nach chirurgischer Behandlung kon-

nten weder Rückfall noch Metastasen nachgewiesen werden.

cutaneous extraskeletal mesenchymal chondrosarcoma in a cat (pages 121–124)

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