Title:
Surgical removal and autologous skin grafting as a successful treatment
of primary cutaneous hemangiosarcoma in a horse.
Lou-Anne Donard, DVM, Dierenkliniek de Bosdreef, Moerbeke-Waas, Belgium
Tatiana Vinardell, DVM, IPSAV, MSc, PhD, Equine Care Group, Mazy,
Belgium
Bernard Boussauw, DVM, ECVS Dipl., Dierenkliniek de Bosdreef,
Moerbeke-Waas, Belgium
Corresponding author: Lou-Anne Donard la.donardvet@gmail.com
Abstract:
This report describes the successful treatment of a cutaneous
hemangiosarcoma of a 12 years old horse presented for evaluation of a
cutaneous mass on the left gluteal region.
Hemangiosarcoma is a rare life-threatening neoplasia that can be
successfully managed when diagnosed and treated at early stages.
Unfortunately, they are often diagnosed at later stages, leading to a
poor outcome and low survival rates. In this report, the horse has been
treated with a complete large surgical excision of the neoplastic
tissue. A good cosmetic outcome as well as a short recovery time has
been achieved with an autologous skin grafting split thickness modified
meek technique. A long-term follow-up of the patient showed no
reoccurrence of the hemangiosarcoma, and successful return to athletic
performance. In the authors knowledge, this is the first equine primary
cutaneous hemangiosarcoma treated with complete excision and
subsequently autologous skin grafting with a long-term follow-up and
good outcome despite the poor prognosis.
Key words:
Neoplasia, modified Meek technique, split thickness skin graft, equine.
Introduction:
Hemangiosarcoma is a malignant neoplasm originated from the vascular
endothelium. It has been rarely described in horses, and often the
diagnosis occurs at later stages of the disease when no treatment
options are available anymore (Beaumier et al., 2020; Ferrucci et al.,
2012). Hemangiosarcoma affects middle aged horses (Johns et al., 2005)
with no breed or sex predilection (Beaumier et al., 2020). Horses can
present systemic clinical symptoms, such as hyperthermia, anorexia and
weight loss (Ferrucci et al., 2012). The clinical presentation of
hemangiosarcomas in the musculoskeletal system includes: growing
cutaneous masses, swollen legs and bleeding wounds as well as hairless
masses and eroded skin (Southwood et al., 2000; Taintor et al., 2014).
The highly aggressive biologic behaviour and high metastatic potential
of this neoplasm leads to a multicentric hemangiosarcoma spreading to
the respiratory system and other internal organs, associated with a
rapid deterioration of the clinical symptoms, including respiratory
complaints, anaemia, haemorrhage and the median survival time after the
onset of clinical signs to euthanasia is 17 days (Reed et al., 2017;
Beaumier et al., 2020; Taintor et al., 2014), therefore a final
diagnosis of hemangiosarcoma is most often obtained post-mortem. The
prognosis is generally considered poor, and surgical resection is often
not attempted due to the rapid growth, high metastatic potential and
risk of recurrence of the tumour.
Herein, the goal of this case report is to describe a case of successful
surgical treatment of a cutaneous hemangiosarcoma using split thickness
skin micrografting in conjunction with complete surgical excision.
Case history:
A 12-year-old Nederland Warmblood gelding was presented at De Bosdreef
equine hospital for fluctuating fever and deformation of the left
gluteus region for a duration of 2-3 weeks. The mass had previously been
injected with corticosteroids by the referring veterinarian without
improvement.
The horse presented very mild hyperthermia (38,4°C), haematology results
showed a decreased white blood cell count (3 600 c/µL) with a normal
neutrophilic count (2300 c/µL), serum amyloid A was elevated (569µg/mL),
serum proteins and electrolytes were within normal limits.
Clinical findings and
diagnosis:
The mass located on the left gluteus region was 6 cm long, 4 cm wide and
2 cm thick, slightly elevated of 3 mm from the skin level and with a
solid consistency (Figure 1a). The mass was not painful at palpation and
no other discomfort or lameness was noted. On ultrasonography, the
deformation was heterogeneously hypoechoic with multifocal fluid
accumulations (hematoma-like appearance) and thickening of the overlying
subcutaneous tissues was observed. A biopsy was obtained and
histopathology revealed a moderately defined infiltrative tumour
consisting of highly variable vascular structures filled with blood and
delineated by a multi-layered highly pleiomorphic endothelium, with oval
nucleus, finely dotted chromatin, small nucleoli and moderate amount of
basophilic cytoplasm. The vascular structures were surrounded by a small
amount of collagenous stroma with multifocal pronounced infiltrate of
hemosiderophages. Immunochemistry results showed that tumoral cells were
positive for Von Willebrand factor, a biomarker used to confirm
hemangiosarcoma in soft tissues (vWF >50%), leading to the
cutaneous hemangiosarcoma diagnosis with a high degree of malignancy
(Figure 2).
Cancer staging was performed and no significant abnormalities were seen
on the thoracic or abdominal region by ultrasound. The horse tested
positive for EHV-2 during hospitalization. Given the localized
neoplastic lesion, the good clinical presentation and the lack of
metastasis at the time of presentation, it was decided to perform a
complete surgical excision of the mass and subsequent skin grafting.
Treatment and outcome:
The hemangiosarcoma was surgically excised under general anaesthesia. A
circular incision of 25 cm in diameter and 6 cm depth was made, and thegluteus medius muscle and fascia were partially removed. The
wound was left open and covered by a wet stent bandage for recovery.
The tumour extended very densely into the deep surgical margins centred
on the lesion. The skin edges were free of neoplasia (>4
cm). The horse received phenylbutazone (2,2mg/kg IV q24h) for 5 days.
Daily wound care was provided post operatively. After 4 weeks, the
granulation tissue covered the entire wound, but due to large extent of
the wound created (25cm) a skin grafting was performed.
Multiple punch biopsies of the granulation tissue were taken to ensure
that the wound bed was free of neoplastic cells, and to subsequently
perform the grafting on healthy tissue. Five biopsy sample were
additionally sent for histopathology, and showed only granulation tissue
with minor to marked superficial pus-like inflammation, without evidence
of neoplasia.
The granulated wound was treated and prepared for grafting with local
antimicrobials, silver sulphadiazine ointment and fusidinic acid cream
alternately for 8 days. Forty-eight hours before grafting, triamcinolone
acetonide cream was used to prevent any further inflammation of the
wound bed after grafting.
Skin grafting was preformed using a modified micro grafting Meek
technique with split thickness skin (1mm) harvested from the ventral
abdomen with a power-driven dermatome, under general anaesthesia. The
wound was trimmed during the procedure and grafted over its entire
length. A pressure stent bandage was placed for 7 days after surgery to
ensure full coverage and pressured contact between the graft and the
granulation tissue. Wound care was given every 5 to 7 days including
bandage change and wound cleaning with sterile swabs and sterile saline
(0,9% NaCl). The wound epithelized and was completely healed 4 weeks
after grafting (Figure 1F). The overall acceptance of the micro grafts
was about 90%, and no signs of infection were noticed at any stage. The
horse was hospitalized for 49 days in total.
Fourteen months after discharge from the hospital, the horse is
performing at his previous level of competition, and is clinically
healthy. From a cosmetic point of view, the surgical wound is almost
completely covered with brown and white hair, the donor site healed
without any complications.
Discussion:
Hemangiosarcoma in horses has been reported to be uncommon and
challenging to diagnose and treat (Beaumier et al., 2020; Taintor et
al., 2014; Fontenot et al., 2018). In horses, the prevalence of
hemangiosarcoma has been reported to be 0 to 0,7% (Ferrucci et al.,
2012) and considering the multicentric form, the diagnosis often occurs
at post mortem (Ferrucci et al., 2012; Fontenot et al., 2018).
In this current case, the location of the neoplastic mass allowed
complete surgical excision before any confirmed metastatic spread, but
cutaneous hemangiosarcomas are rarely encountered as a retrospective
study on 35 cases of equine hemangiosarcoma showed a cutaneous
prevalence of 24% (Southwood et al., 2000).
Surprisingly the precious time that has been lost in between diagnosis
and treatment did not change the outcome of that case, this observation
supports the belief that 2 different forms of hemangiosarcomas are
described: the slowly progressive or the aggressive form rapidly growing
(Johns et al., 2005). In this case the horse was diagnosed with the
slowly progressive form.
The genetic implication of hemangiosarcoma has been suspected in several
cases (Fontenot et al., 2018), but the genetic predisposition or
implication in that case could not be proven since no genetic test was
performed.
Although the high malignancy and risk of metastasis of this type of
neoplasia generally results in a poor prognosis with a very short
survival time (Reed et al., 2017), this was not the case in this report.
Metastasis usually occur in the lungs and kidneys regions leading to a
higher risk of recurrence (Beaumier et al., 2020). In this particular
case, no abnormality was detected by ultrasound.
The typical ultrasonographic appearance in cutaneous hemangiosarcomas is
a hematoma like image (Taintor et al., 2014, Ferrucci et al., 2012),
with alternating hyperechoic and hypoechoic images as it was observed in
this case. The hyperthermia at the time of arrival could be explained by
the positive EHV 2 test performed during hospitalization, even though it
has also been described in horses diagnosed with hemangiosarcoma
(Ferrucci et al., 2012).
A definitive diagnosis of hemangiosarcoma can only be made on histology
either pre- or post- mortem, with biopsies or complete mass excision
being the most reliable. In this case, the definitive diagnosis was
confirmed twice, on the biopsy taken at presentation and on the complete
mass excision at the time of surgery. Hemangiosarcomas can be classified
histologically either as a well or poorly differentiated neoplastic mass
with variable numbers of mitotic figures seen in the histological
samples (Taintor et al., 2014). It also has been described to show
expansive compressive infiltrative neoplasm, irregular lining, blood
filled spaces and channels resembling vascular structures which were
seen in this particular case.
One complication of surgical excision in neoplastic masses with wide
margins is the lack of skin coverage after their resection. Among the
different grafting techniques available for horses, the modified Meek
technique is considered the most appropriate treatment if the material
and technical skills are available. It is usually advised to prepare any
wound wider than 4 x 4 cm for skin grafting in a timely manner. The
required amount of time needed for a wound of this size to heal by
second intention was estimated for at least 6 months, even with the
appropriate wound care. Such an extended period of hospitalization
results in high costs and a prolonged resting period, particularly
inconvenient for competing sport horses. Furthermore, the cosmetic
result was also an important factor for the owners, and the modified
Meek split thickness micro grafting was the technique of choice for this
case as it provided smaller and more flexible scars covered with the
hair of the donor site colour (Wilmink et al., 2010). The optimal result
observed in this study, were due to the high rate of epithelialization
and the excellent wound contraction, that reduced the remaining scar
tissue at the end of the healing process.
Most of the cases diagnosed are multicentric hemangiosarcomas. Even
though this particular case has shown very good evolution and no
recurrence of clinical symptoms after 12 months, it is more likely that
this cutaneous hemangiosarcoma was the site of primary neoplasia
(Ferrucci et al., 2012) and has been treated before dissemination.
Conclusion:
Primary hemangiosarcoma in middle aged horses is a rare, highly
malignant condition with a high risk of metastasis and poor prognosis.
However, a favourable outcome after treatment by complete surgical
excision in this case was possible due early detection and treatment
before metastatic spread. The resulting large excision could be treated
successfully post-surgery using skin grafting to achieve the most
favourable cosmetic outcome, and to reduce the closure time
significantly. Despite the poor prognosis given to horses diagnosed with
hemangiosarcoma, this patient is free of symptoms, 14 months after being
diagnosed.
Figure legends:
Figure 1: A: The mass before excision, located in the centre of the
clipped area, cranial is to the left. The second mass cranioventral to
the clipped area (white arrow) was identified as a benign melanoma. B:
Surgical site 5 days after excision. C: Surgical site 45 days after
excision: the granulation tissue is prepared and ready for grafting. D:
8 days after grafting. E: 11 days after grafting. F: 27 days after
grafting. G: 8 months after grafting; scale bar 10 cm.
Figure 2: A: Histologic appearance of the hemangiosarcoma stained with
hematoxylin-eosin showing highly variable vascular structures filled
with blood and delineated by a single- or multilayered strongly
pleiomorphic endothelium, with oval nucleus (black arrows), B: Von
Wilebrand factor immunohistochemichal stain exhibiting positive
neoplastic cells (black arrows).
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