Mastectomy and castration

Mastectomy and castration

1. Orchiectomy indications

   • Prevents breeding
   • Reduces aggression and roaming behaviours
   • Reduces the risk of prostatic disease, perineal hernia and perianal adenoma
   • Removes risk of testicular neoplasia

2. Dog castration

   • Prescrotal
     • Most common
     • Done for elective castrates
     • Push testicle into prescrotal position
     • Incise skin longitudinally over testicle
   • Scrotal ablation (tumours)
   • Perineal castration
   • Open
     • Open parietal tunic
     • Risk of evisceration
     • Risk of peritonitis
     • Better haemostasis
     • Incise parietal tunic not tunica albuginea
     • Break down the ligament of the tail of the epididymis and exteriorise
     • Separate ductus and vessels and ligate separately
   • Closed
     • Parietal tunic intact
     • Less effective haemostasis achieved
     • Almost no risk of evisceration/peritonitis
     • Continue incision into parietal tunic but do not incise it
     • Squeeze out of incision and break down fascia/elevate with a dry swab
     • Triple clamp ensuring that there is a transfixing sututre in cremaster
       • +/- another transfixing or circumferential
       • In crush line of proximal clamp
   • Pre - operative checks
     • Check both testicles are in the scrotum
     • Check the sex of cats in particular
   • Check haemorrhage before releasing stump
   • Closure
     • Close parietal fascia
     • Close skin with subcuticular sutures

3. Cat castration

   • Incise longitudinally through scrotum over testicle and avoid penis
   • Continue dissection through parietal tunic or keep intact
   • Knot spermatic cord around itself or ligate
   • Remove each testicle through a separate incision

4. Complications with castration

   • Intra abdominal haemorrhage - expl. coeliotomy
   • Herniation
   • Dehiscence
   • Incontinence
   • Scrotal haematoma - usually cutaneous vessel

5. Cryptorchidism

   • >2mo it is unlikely there will be any further descent
   • Congenital failure of testicles to descend into the scrotum
   • Location
     • Inguinal
       • Incise directly over testicle
       • Perform open castration
     • In inguinal canal
       • Difficult to find
     • Abdominal
       • Caudal midline coeliotomy
       • Find by tracing testicular vessels from kidney
       • Trace DD from prostate

6. Testicular neoplasia

   • Common types with cryptorchids
     • sertoli cell tumour
     • Seminoma
   • Types
     • Sertoli cell
       • Paraneoplastic syndrome
         • Allopecia
         • Feminisation
         • Myelosuppression
         • Hyperpigmentation
     • Seminoma
     • Interstitial cell tumour
   • Mets
     • 10% of sertoli
     • Interstitial cell
   • Castrate-usually with scrotal ablation

7. Mammary gland neoplasia

   • Malignancy rate
     • 35-50% in dogs
     • 90% in cats
     • Mets by haematogenous and lymphatic routes
   • Influence of neutering
     • Protective effect by early neutering
     • Protective effect lost after 2nd oestrus
     • Risk
       • 0.05% before 1st oestrus
       • 8% after first oestrus
       • 26% after second oestrus
   • Benign Tumours
     • Adenoma
     • Benign mesenchymal tumour
     • Mixed mammary - fibroadenoma
   • Malignant tumours
     • Carcinoma
     • Sarcoma
     • Inflammatory carcinoma - aggressive
     • Carcinosarcoma
   • Feline
     • 99% entire female cats
     • Rapid growth, early met
     • Poor prognosis

8. mammary tumour oncology

   • Clincal exam
     • Most frequently in caudal glands
     • Fixed masses are uncommon and require more aggressive dissection
     • Ulcerated - inflammatory - poor prognosis
   • Staging
     • Histopath
       • FNA
       • Tru cut
       • Incisional
       • Excisional - may be curative - preferred
     • Evaluate for thoracic mets
     • X ray
       • Thoracic
     • canine: 25-50% mets by time of diagnosis
     • Ultrasound sublumbar LN
     • Palpate local LN
   • DDx
     • Mastitis
     • Other skin neoplasms
     • Hypertrophy
     • Fibromatous hyperplasia in cats

9. Mammary tumour surgery

   • Mastectomy is the mainstay
   • Outcome not affected by surgical technique unless complete resection
   • Lumpectom
   • Regional
   • Bilateral mammary strip
     • Not done in dogs staged
     • Y shaped removal in cats - excess skin
   • Unilateral mammary strip
     • Dogs
       • Multiple glands on one side affected
       • As staged procedures 3-4 apart if both sides affective
     • Cats
       • May reduce local recurrence compared to lumpectomy
   • Prognosis
     • Benign tumours
       • Excellent
     • Melignant tumours
       • 50% of cases will die within 2y
       • Poor prognosis if mets at time of Dx
       • Poor if inflammatory