Surgical excision of trichoblastoma in German Shepherd Dog-a case report

Introduction

In veterinary medicine, benign hair follicle tumors include trichoblastomas, trichoepitheliomas, pilomatricomas, tricholemmomas and trichofolliculomas (Gross et al., 2005) [1] . Canine trichoblastoma is a benign cutaneous tumour derived from the remnants of the primitive hair germ of embryonic follicular development. It most commonly located on the head and neck (Goldschmidt et al., 2016) [2] . Incidence of Trichoblastomas was 2.0-2.6% in dogs and most affected lesions are found in middle-aged and old animals (6-9 years of age) (Abramo et al., 1999) [3] . Hair follicle tumors often affect animals with short and thick hair viz, German shepherd, Labrador, Cocker spaniels, Bassett hounds and mixed-breed dogs (Gross et al., 2005; Goldschmidt et al., 2016) [1,2] . The present case was successful surgical management of trichoblastoma present at supra-orbital region region in nine-year old German Shepherd dog.

Case details

A nine-year-old, female German shepherd dog was presented with the complaint of having a mass over the supra-orbital region for the past seven months which had been gradually increased in size. Clinical examination revealed a solitary, spherical, firm and non-ulcerated round growth over the supra-orbital region (Fig. 1). There were no signs of palpable peripheral lymph node enlargement. All the biochemical and haematological parameters were within the normal range. Based on the history, clinical examination the case was suspected for cutaneous tumor and surgical excision was decided upon and dog was prepared for aseptic surgery as per the standard protocol.

Surgical treatment

The site was prepared for surgical intervention as per the standard procedure. The dog was premedicated with inj. Atropine sulphate @ 0.04 mg/kg body weight S/C and inj. Xylazine hydrochloride @ 1 mg/kg body weight I/M and butorphanol @ 0.2mg/kg body weight intramuscularly. General anaesthesia was induced with intravenous injections of Ketamine and diazepam I/V (Inj. ketamine @ 5mg/kg + Inj. Diazepam @ 0.25 mg/Kg) and maintenance with 2% isoflurane. Dog was positioned in lateral recumbency with the affected side up and the growth visible towards the surgeon. Surgical site was prepared (Fig. 2) and an elliptical incision was made around the base of the growth and the mass was excised by blunt dissection. The subcutaneous tissue and skin were sutured by following the standard operating procedure (Fig 3). The radically excised tissue sample was processed, evaluated histopathologically.It revealed elevating the overlying epidermis and compressing adjacent adnexa was densely cellular focally expanding the dermis and subcutis, encapsulated, well-demarcated, circumscribed, multilobulated neoplasm composed of basaloid polygonal cells arranged in variably sized islands. The cell islands were separated and surrounded by dense, often hyalinized collagenous stroma. The neoplastic cells exhibited oval normochromatic nuclei with fine stippled chromatin, inconspicuous nucleoli, scant eosinophilic cytoplasm and variably distinct cell borders. The mitotic rate averages less than 2 per 10 high power field (mitoticindex <2/hpf). The cells displayed minimal anisocytosis and anisokaryosis (Fig. 4). Based on above findings it was interpreted as trichoblastoma of ribbon type. Post-operatively, the animal was administered Inj. Intacef (Ceftriaxone) @ 25 mg/kg I/V b.wt for 5 days and Inj. Melonex (Meloxicam) @ 0.2 mg/kg b.wt. I/M for 2 days. Antiseptic wound dressing with povidone iodine was done to protect surgical site. The skin sutures were removed on 12 th post-operative day. The case recovered uneventfully and no relapse of the condition was seen during the follow up period of study of eight months.

Discussion

Trichoblastoma is usually present as a solitary, firm, alopecic, nodular dome shaped or polypoid growth (Yoon et al., 2014) [4] . Typically, trichoblastoma are slow growing, freely moveable beneath the skin most commonly located on the head and neck (Mauldin and Kennedy, 2016) [5] . In the present case, the growth on the supra-orbital region had been gradually increasing in size since past six months. It was solitary, spherical, firm, non-ulcerated round and pink with haemorrhages. Most of the tumors are 1 to 2 cm in diameter. However, rarely much larger lesions may occur. Tumour mass was excised surgically as per standard protocol.

Haydardedeoğlu et al. (2015) [6] , Winkler (2016) [7] and Rani et al. (2021) [8] opined that surgical excision is the treatment of choice. Histologically, trichoblastoma is classified into ribbon, trabecular, granular cell, spindle cell or clear cell types. Here in this case report the trichoblastoma was ribbon type. Most cases are a mixture of these patterns with a predominance of ribbon epithelial aggregates surrounded by fibrous stroma (Gross et al., 2005 [1] and Campos et al., 2014 [9] ). The dog recovered uneventfully and there was no recurrence 8 months after surgery. Similar findings were also recorded by Campos et al. (2014) [9] , Winkler (2016) [7] and Rani et al. (2021) [8] .

Conclusion

A case of trichoblastoma-ribbon type located over the supraorbital region in a German shepherd dog and its successful surgical management is reported.

Conflict of Interest Not available

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References

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