Page 1097 - Problem-Based Feline Medicine

52 – THE CAT WITH NON-HEALING WOUNDS 1089

Prognosis See main references on page 25 for details (The Cat
With Signs of Chronic Nasal Disease) and page 847
Prognosis is good if the allergy is identified, and signs
(The Cat With a Head Tilt, Vestibular Ataxia or
can be controlled with specific therapy.
Nystagmus).
SQUAMOUS CELL CARCINOMA (SCC)** Clinical signs
Typically there is a firm swelling over the bridge of
Classical signs
the nose or planum nasale giving the appearance of a
● Proliferative and/or ulcerative lesions on Roman nose, or there is a polyp-like mass visible in
non-pigmented facial extremities. the nasal opening.
Cutaneous lesions occur in up to 40% of cases, and
See main references on page 1069 for details (The Cat
consist of papules or nodules varying from 0.1–1 cm
With Skin Lumps and Bumps).
in diameter.
Lesions may ulcerate and exude serous fluid, or remain
Clinical signs as intact nodules.
Squamous cell carcinoma affects any gender or breed Skin lesions may be single or multiple, and occur
of cat, and the average age of affected cats is 9 years. alone, or with involvement of other organs.
The pinnae, philtrum, nares, forehead and palpe- Lesions favor face, pinnae and paws, and can occur
brae are the most affected sites, especially in non- with or without co-existent respiratory, CNS or oph-
pigmented, thinly haired areas. thalmic signs.

Lesions are multiple in 45% of affected cats.
Diagnosis
Lesions may be proliferative or ulcerative, and occa-
Diagnosis is based on clinical signs and demonstra-
sionally cutaneous horns are seen.
tion of the organism in association with the lesion.
SCC tends to be locally invasive and slow to metasta-
Cytological examination of fluid draining from
size.
a skin lesion, nasal exudate, a fine-needle aspirate of
Nail-bed SCC behave more aggressively. a skin nodule, spinal fluid, vitreal or aqueous para-
centesis stained with new methylene blue (NMB)
and Gram stains usually demonstrates the organism.
Diagnosis
Organism is yeast-like (5–15 μm) and is surrounded
Diagnosis is based on histopathology of the lesion by a wide, clear capsule.
which shows irregular cords of keratinocytes which
Serology to detect cryptococcal capsular antigen in
breach the dermo–epidermal junction and invade the der-
blood, CSF or urine is useful if positive. Note that this
mis. Cellular atypia, dyskeratosis, loss of cellular orien-
test may be negative when the disease is localized to the
tation with or without solar elastosis may be evident.
skin.
Tissue biopsy can be used to identify the pleomorphic
CRYPTOCOCCOSIS*
yeast-like organisms with a refractile halo (mucinous
capsule). PAS and methanamine silver stains make the
Classical signs
organisms more readily detectable.
● Soft tissue swelling over the bridge of the
nose (Roman nose) or polyp in nasal
opening. Differential diagnosis
● Single or multiple papules or nodules in
Differential diagnoses that should be considered for
the skin which may ulcerate.
the cutaneous form of cryptococcosus include feline