Cysts Figure 2

Figure 2: Sebaceous cyst in male rat (Schnapps).
Case history and photos


Schnapps, a 13-month-old male, Agouti self. Pet shop rat, so no genetic knowledge. The alpha (dominant) rat among his cage mates.

Clinical signs

Cyst was initially discovered at the start of August, and appeared as a small hard lentil-sized lump within the skin, on right hand side of his back.


Fine needle biopsy showed skin oil only, and identified as sebaceous cyst.


When first identified it did not appear to be bothering him at all. The vet instructed to continue to observe and return if there appeared to be any change.

The growth was checked again a month or so later as it had grown substantially.

The cyst was now about 1cm in size, flattened disc shape. A biopsy was done at this time, and showed the
same oil content. No additional signs of infection or growth involved. Again it did not appear to be bothering him so observation continued.

In late November, Schnapps started to bother the lump. The surface was red with a small amount of bleeding. The cyst was now a hard lump, 1.5cm in width and a flattened disc shape. On vet examination, a small amount of brown pus was squeezed out. When viewed under a microscope it showed lots of bacteria.

The cyst was lanced and the lump popped out easily and freely, leaving a clean open wound. There was no further bleeding or pus. The wound was flushed with saline and closed with two staples.

He was given Baytril (an antibiotic) for 5 days, and Metacam (an NSAID to reduce inflammation) for 3 days.


Healed without complication.


sebaceous cyst

Photo 1: Shows shape of sebaceous cyst and size in centimeters.

closed wound

Photo 2: Shows closure of wound site.

Case history and photos courtesy of Robyn Arthur of The Dapper Rat,, in
collaboration with Larissa Ladyko B.V.Sc.


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