Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 203
Fig. 2-183 A and B, A 3-year-old
spayed cat with a history of weight
loss and anorexia occurring over several
months. The cat had developed
respiratory distress. There is a
marked increase in pulmonary interstitial
densities distributed throughout
the lung. The infiltrate is more
severe in the right caudal lung
lobe. The pulmonary vascular structures
are obscured. Many end-on
bronchi are identified. Diagnosis:
Lymphoma. The pulmonary infiltrate
was thought to represent an
allergic or parasitic pneumonia. The
diagnosis of lymphoma was made at
necropsy. A similar pulmonary pattern
may be observed with feline
infectious peritonitis.
A
B
O L D AG E : I N T E R S T I T I A L F I B R O S I S
Chronic disseminated or diffuse interstitial pulmonary patterns, including fine linear and
reticular patterns as well as calcified, discrete nodules, may be observed in pets with pulmonary
fibrosis. 73,573-575 This may be due to idiopathic fibrosis, which typically is seen in
younger dogs with clinical signs of respiratory disease, or due to aging in older dogs and
cats that usually are not clinically affected. The calcified nodules may be either old granulomas
that dystrophically calcified or pulmonary osteomata, islands of bone within the
lung of unknown causes. 73 The general causes of these changes may include long-term
inhalation of irritating smoke or dust particles or prior pulmonary disease, which has
healed leaving scarring within the lung.