here - Australian College of Veterinary Scientists

More documents

Recommendations

Info

Introduction 78 Histopathological review of equine sarcoids ACVSC Proceedings Dermatology Chapter Science Week 2005 Jenny Charles The sarcoid is the most common skin tumour of horses, donkeys and mules and is a locally invasive fibroblastic neoplasm which lacks metastatic potential. Individual animals may have multiple tumours, either synchronously or sequentially. Although spontaneous regression of equine sarcoids after a protracted growth period has been reported, it is a rare occurrence and most lesions require surgical excision, cryosurgery, immunotherapy, radiation brachytherapy or other intervention. Local recurrence of sarcoids is common and is expected of incompletely excised lesions. There is considerable evidence implicating papillomaviruses (closely related to bovine papillomaviruses types 1 and 2) in the aetiopathogenesis of equine sarcoids. Gross appearance Most sarcoids are grossly characterised by firm dermal thickening by cream-white tissue with thickening, roughening and hyperkeratosis of the skin surface. The tumour may be sessile, domed or pedunculated and well demarcated or poorly circumscribed. The surface of protruberant sarcoids is commonly ulcerated. The gross appearance of many sarcoids may closely mimic that of exuberant granulation tissue and, in ulcerated tumours, granulation tissue may coexist with neoplastic tissue and contribute to lesion growth. Various classification schemes have been proposed by equine clinicians based upon the gross appearance of sarcoids. These schemes are essentially for descriptive purposes. The gross appearance of sarcoids may alter over time, both as part of neoplastic progression and in response to lesion abrasion, ulceration or iatrogenic trauma. The anatomic location of a sarcoid may also influence its gross appearance. Six variants have been described: occult, verrucous, fibroblastic, nodular, mixed and malevolent. Occult sarcoids emerge as one or a few, well-defined, annular areas of hair loss with variable scaling or crusting. These lesions, which may closely resemble those of dermatophytosis or focal frictional injury, may gradually expand or remain static for months or years before ultimately evolving into firm dermal or subcutaneous nodules or relatively sessile, hyperkeratotic verrucous lesions. Abrasion or surgical biopsy of occult sarcoids may provoke vigorous fibroblastic proliferation and emergence of a more aggressive fibroblastic variant. Occult sarcoids may occur at
any anatomic location but commonly arise on the medial thigh, prepuce, neck and face. Verrucous (warty) sarcoids are usually less circumscribed than occult sarcoids and protrude as palpable masses due to an increased dermal neoplastic component. They may be sessile or pedunculated. The degree of overlying hyperkeratosis and scaling is variable but there is often a partially or totally alopecic, dry, cauliflower-like surface. This variant is also relatively slow-growing but a more aggressive fibroblastic type may emerge following trauma. Verrucous sarcoids need to be distinguished from squamous papillomas induced by equine papillomavirus and from chronic frictional irritation. Verrucous sarcoids are most commonly located in the axillary and inguinal areas. Fibroblastic sarcoids involve both the dermis and subcutis, with the extent of deep dermal and subcutaneous infiltration often being underestimated on clinical examination. This variant typically manifests as a protruberant, firm to fleshy, ulcerated mass which closely resembles exuberant granulation tissue. It is wellvascularised and prone to bleed when minimally traumatised. Most sarcoids arising on the brisket or limbs are of fibroblastic appearance. Fibroblastic sarcoids may enlarge rapidly over weeks to months and then stabilise and persist for years. Differential diagnoses for such lesions include, in addition to proud flesh, squamous cell carcinoma, botryomycosis, habronemiasis, phycomycosis, fibrosarcoma and peripheral nerve sheath tumour. Nodular sarcoids usually involve only the subcutis as one or multiple, spherical, mobile nodules usually covered by intact skin of normal appearance. Intradermal nodular sarcoids may occasionally be seen and the overlying skin may appear thin and shiny. Sarcoids involving the palpebral margins are typically nodular and this variant is also commonly found on the medial thigh, prepuce and inguinal area. Nodular sarcoids, being well demarcated, are amenable to surgical excision but incomplete excision (or traumatic ulceration of the overlying skin) may encourage emergence of a more aggressive fibroblastic variant. Nodular sarcoids may grossly resemble nodular necrobiosis (equine eosinophilic collagenolytic granuloma) and other mesenchymal tumours such as melanoma, fibroma or peripheral nerve sheath tumour. Mixed sarcoids present with a combination of the gross characteristics of two or more of the verrucous, fibroblastic and nodular forms and may represent a transitional phase as a more rapidly growing and locally aggressive neoplasm emerges from a previously stable focus. Mixed sarcoids are most commonly found in the axillary and inguinal areas and on the face. Malevolent sarcoids are rare, highly invasive variants which infiltrate along lymphatics to produce nodular cording and multiple ulcerated fibroblastic nodules. The neoplastic tissue may extend along lymphatics to involve regional lymph nodes. Most malevolent sarcoids have been observed following intereference with a ACVSC Proceedings Dermatology Chapter Science Week 2005 79
Page 1 and 2:
Australian College of Veterinary Sc
Page 3 and 4:
Australian College of Veterinary Sc
Page 5 and 6:
3.00 Afternoon tea 3.30 How I treat
Page 7 and 8:
Dr Jennifer A. Charles BVSc MVS Dip
Page 9 and 10:
Scientists in Feline Medicine in 19
Page 11 and 12:
IgE-bearing cells have been demonst
Page 13 and 14:
years, median age 6.5 years, with a
Page 15 and 16:
dusts, grain smuts, moulds, danders
Page 17 and 18:
References: Evans AG, Paradis MR, &
Page 19 and 20:
Comparatively simple, cheap and eff
Page 21 and 22:
TABLE 1: CURRENT ALLERGENS SELECTED
Page 23 and 24:
AmericanCockroach Cockroach mix
Page 25 and 26:
Patient Preparation Drug Withdrawal
Page 27 and 28: Each injection site is visually exa
Page 29 and 30: References 1. Scott DW, Miller WH:
Page 31 and 32: Intradermal Testing (IDT) in Horses
Page 33 and 34: TABLE 2 Additional allergens used i
Page 35 and 36: Allergen Positive reactions Mosquit
Page 37 and 38: much higher and corresponded to the
Page 39 and 40: and this and other uncontrolled tri
Page 41 and 42: Introduction Diagnostic Approach to
Page 43 and 44: Wheals vary in size and shape and q
Page 45 and 46: References Evans AG, Paradis MR & O
Page 47 and 48: Introduction: Equine Chronic Urtica
Page 49 and 50: Acute treatment - Epinephrine 1:100
Page 51 and 52: anecdotal success with use of human
Page 53 and 54: an 80:20 mixture of evening primros
Page 55 and 56: Clinical approach to the horse with
Page 57 and 58: identify plants in a pasture that m
Page 59 and 60: Equine sarcoidosis Sonya Bettenay T
Page 61 and 62: described as a possible feature of
Page 63 and 64: others 2001), isotretinoin(Waldinge
Page 65 and 66: 12. LeGall, F., Loeuillet, L., Dela
Page 67 and 68: Introduction The equine sarcoid: an
Page 69 and 70: Clinical Presentation Small fibrous
Page 71 and 72: Assessment should be made on the fo
Page 73 and 74: (ix)Bone becomes devitalized if inc
Page 75 and 76: and mitomycin C have been used. All
Page 77: Owen LN & Barnett KC (1983) - Treat
Page 81 and 82: epidermis may be histologically nor
Page 83 and 84: References D.C. Knottenbelt, S. Edw
Page 85 and 86: indicated. Each sample for culture
Page 87 and 88: Proper dosage and proper duration a
Page 89 and 90: 2. Affect on the horse and 3. Affec
Page 91 and 92: Affected horses usually scratch and
Page 93 and 94: • Cattle ear tags impregnated wit
Page 95 and 96: How I treat: equine pemphigus folia
Page 97 and 98: Treatment of pemphigus foliaceus in
Page 99 and 100: SCOTT, D.W., WALON, D.K., SLATER, M
Page 101 and 102: Diagnosis History of access of hors
Page 103 and 104: These vaccines are not manufactured
Page 105 and 106: References Alfaro AA & Mendoza L (1
Page 107 and 108: y a variety of fungal metabolites.
Page 109 and 110: Authors recommendations: 1. Both Im
Page 111 and 112: chorioptic mange by the author (Lit
Page 113 and 114: Clinical Disease The clinical resul
Page 115 and 116: treatment options have been used. P
Page 117 and 118: Notes ACVSC Proceedings Dermatology
show all

here - Australian College of Veterinary Scientists

Create successful ePaper yourself

Delete template?

Save as template?