Page 74 - Problem-Based Feline Medicine

66 PART 2 CAT WITH LOWER RESPIRATORY TRACT OR CARDIAC SIGNS

PULMONARY NEOPLASIA Diagnosis
Chest radiographs demonstrate a solid tissue mass(es)
Classical signs or nodular interstitial pattern.
● Sensitivity is limited to masses > 10 mm diameter,
● Non-productive cough, with or without
and multiple views are important to maximize diag-
hemoptysis.
nosis. Hilar lymphadenopathy may be present.
● Reduced activity.
● Tachypnea and dyspnea – subtle to Other imaging modalities, such as CT or MRI are use-
marked, especially if pleural effusion is ful if available.
evident.
Biopsy of mass(es) is required for definitive diagno-
● Fetid halitosis.
sis, as well as for distinguishing the origin of tumor.
● Mass lesion radiographically.
● Biopsy options include percutaneous needle aspira-
● Anorexia, weight loss, muscle wasting.
tion or core biopsy, bronchoscopy, or unguided
bronchioalveolar lavage, or transbronchial lung
Pathogenesis biopsy.
● Ultrasound is often a poor tool to guide
Pulmonary neoplasia may be primary or result from
percutaneous biopsy needles, unless the entire
secondary metastases from distant neoplasms.
lung lobe has become consolidated, as the sonic
Primary tumors include bronchogenic carcinoma, beam is reflected by any aerated lung tissue.
pulmonary adenocarcinoma and squamous cell car- ● Triangulating the landmarks based on two orthogo-
cinomas. nal radiographic views is extremely effective for
percutaneous biopsy.
Secondary metastatic tumors include a wide variety
● Transbronchial cytology (TTW or BAL) is often
of carcinomas (i.e., mammary adenocarcinomas) and
disappointing, due to the interstitial nature of the
sarcomas (i.e., osteosarcoma), and local metastases
lesion.
from primary lung tumors.
● Transbronchial lung biopsy is a promising tech-
Pleural malignancy may cause dyspnea, either by the nique for obtaining samples for histopathology, but
space-occupying nature of the mass, or from secondary is only available at some institutions.
pleural effusion.
Surgical biopsy may be performed via thoracotomy,
generally during lobectomy.
Clinical signs
● Local lymph nodes should be aspirated or biopsied
Reduced activity with reluctance to play or run may be for staging.
observed.
Thoracocentesis and cytology of pleural fluid is occa-
Inappetance or anorexia and weight loss are often sionally diagnostic if neoplastic cells have exfoliated.
present.
Fetid halitosis may be noticed on physical exam or by Differential diagnosis
the owner.
Infectious disease, especially fungal and parasitic gran-
A non-productive cough, with or without hemoptysis ulomas, foreign body reactions, inflammatory granulo-
is sometimes present. Dyspnea (inspiratory and expira- matous lesions, and lung lobe torsions may mimic
tory) and respiratory distress may be evident in the later neoplastic disease clinically and radiographically.
stages, or if pleural effusion develops.
Pleural effusion results in muffled heart and lung sounds Treatment
ventrally and worsening of dyspnea in lateral recumbency.
Surgical resection is the treatment of choice for soli-
Very rarely, lameness occurs from peripheral appendic- tary primary neoplasms. Cure or long-term remission is
ular bone lesions of hypertrophic osteopathy. possible with wide surgical margins. If non-resectible,