Dog & Cat HospitalCalabasas

Patient Education

Excisional Biopsy & Mass Removal

Removing a skin or soft-tissue mass is often both the biopsy and the cure — the excised tissue goes straight to the lab to name the tumor type and confirm that clean margins were achieved.

Excisional biopsy is the surgical removal of an entire mass — rather than just a small sample — along with a margin of surrounding healthy tissue. In a single procedure, Dr. Schulman removes the growth and sends the specimen to a veterinary pathologist who identifies the tumor type, grades its aggressiveness, and reports whether the edges (margins) are clear of tumor cells. For many low-grade or benign lumps, excisional biopsy is both the definitive diagnosis and the definitive treatment. At Dog & Cat Hospital Calabasas we combine on-site diagnostics, in-house pre-surgical bloodwork, and board-certified surgical technique to give your pet the best chance of a clean removal on the first attempt.

Why It's Recommended

Not every lump needs excisional biopsy, but surgery becomes the preferred option when:

  • A fine-needle aspirate (FNA) is non-diagnostic or raises concern for a type of cancer that behaves better with wide margins
  • The mass is growing, changing shape, or causing discomfort
  • The location makes incisional biopsy technically difficult or likely to seed tumor cells
  • Imaging (ultrasound or CT) suggests the mass is self-contained and resectable

Removing the whole mass at once avoids a second anesthetic event, reduces the chance of incomplete removal, and gives the pathologist the most informative specimen possible.

How the Procedure Works

Excisional biopsy is performed under general anesthesia with continuous monitoring. The steps:

  • The mass and the planned margin of normal tissue around it are marked before incision
  • The surgeon dissects cleanly around and below the growth, keeping the specimen intact
  • Hemostasis (bleeding control) is achieved with electrosurgery or ligatures
  • The wound is closed in layers — subcutaneous tissue first, then skin — to minimize tension
  • The specimen is fixed in formalin and submitted for histopathology (microscopic tissue analysis)

Results typically return within five to seven business days. The pathology report guides whether any follow-up treatment — additional surgery, radiation, or chemotherapy — is recommended.

Found a lump on your pet?

Book an Appointment

Preparation

Before scheduling surgery, the team will review any prior aspirate or imaging results. Pre-anesthetic bloodwork and, when indicated, chest X-rays are performed to screen for systemic disease or evidence of spread. Withhold food the evening before surgery; water is usually permitted until a few hours before the procedure. Bring a list of any medications or supplements your pet takes, as some (including fish oil and certain herbal products) affect clotting and should be paused beforehand.

Recovery & Aftercare

Most pets go home the same day and recover quickly. Aftercare typically involves:

  • An Elizabethan collar (e-collar) to prevent licking or chewing the incision
  • Activity restriction — no running, jumping, or swimming — for 10 to 14 days
  • Daily incision checks for redness, swelling, or discharge
  • Pain medication for the first few days; most pets are comfortable within 48 hours
  • A recheck appointment to remove sutures and review the pathology report together

If the pathology report shows incomplete margins or an aggressive tumor type, follow-up options can be discussed at the recheck visit while the wound is still healing well.

Risks & What to Expect

Excisional biopsy carries the general risks of any surgical procedure under anesthesia — infection, bleeding, and wound dehiscence (opening) — all of which are uncommon. The main oncologic risk is incomplete excision: if the pathologist finds tumor cells at the margin, a second surgery or adjuvant therapy may be needed. This is more likely with large or poorly defined tumors, which is why pre-surgical imaging helps plan the approach. The surgical team will explain what the pathology report means and what, if anything, comes next — you won't be left to interpret it alone.

Frequently Asked Questions

1What is the difference between a fine-needle aspirate and an excisional biopsy?
A fine-needle aspirate collects individual cells with a needle and gives a quick, preliminary cell type; excisional biopsy removes the entire mass so a pathologist can analyze tissue architecture, grade the tumor, and assess whether the edges are clear. Excisional biopsy provides far more complete information.
2How much does excisional biopsy cost for a dog or cat?
Cost depends on the mass location, its size, anesthesia time, and the pathology lab fee. We provide a written estimate at the consultation that covers surgery, monitoring, and histopathology.
3What if the margins are not clean?
Incomplete margins mean some tumor cells were left behind, which increases the chance of regrowth. Depending on the tumor type and grade, options include a second wider excision, radiation therapy, or watchful monitoring — the pathology report guides the conversation.
4Is every lump cancer?
No — many removed masses turn out to be benign lipomas, cysts, or inflammatory lesions. Histopathology is the only way to know for certain, which is why submitting the tissue is always recommended even when a mass looks innocuous.
5My dog's lump has been there for years — does it still need to be removed?
Slow growth does not rule out malignancy, and some tumors stay small for a long time before changing behavior. Scheduling an evaluation lets the surgeon assess size, depth, mobility, and growth rate to advise whether removal is appropriate now or worth monitoring.
6How long does it take to get the biopsy results?
Histopathology results typically come back within five to seven business days from a veterinary pathology laboratory. We'll contact you as soon as the report arrives and schedule a follow-up to review findings together.
7Will my pet need chemotherapy or radiation after mass removal?
Most benign or low-grade masses require no additional treatment after clean excision. High-grade or incompletely excised malignant tumors may benefit from follow-up therapy; the pathology report and an oncology referral will clarify the recommendation.
8Is anesthesia safe for an older dog or cat?
Age alone is not a disqualifier. Pre-anesthetic bloodwork, tailored drug protocols, and continuous monitoring throughout surgery significantly reduce risk even in senior patients. The surgical team will discuss your pet's individual risk profile at the pre-surgical consultation.

Related

ConditionsCancer, Masses & Lumps

Found a lump on your pet?

Our board-certified surgical team will evaluate the mass, recommend the right diagnostic approach, and plan a removal that gives your pet the best chance at clean margins on the first attempt.

Book an Appointment