Page 1676 - Cote clinical veterinary advisor dogs and cats 4th

Pulmonary Nodules 841

ASSOCIATED DISORDERS • Development of metastasis is a complex, Eosinophilia may accompany parasites or
eosinophilic bronchopneumopathy.
Paraneoplastic syndromes are reported to multistep process, and failure to complete • Pleural effusion, if present, should be sampled
VetBooks.ir lung neoplasms (hypertrophic osteopathy; metastatic focus. It is estimated that < 1 in and evaluated with fluid and cytologic Diseases and Disorders
any of the steps prevents development of a
occur secondary to primary or metastatic
analysis (pp. 1164 and 1343).
100 neoplastic cells that leave the primary
hypercalcemia; fever; feline lung-digit syn-
drome; elevated ACTH with associated signs
tumor survive the metastatic cascade.
of hyperadrenocorticism). • The multistep process includes induction of Advanced or Confirmatory Testing
neovascularization, detachment of the tumor • Ultrasonographic studies
Clinical Presentation cell from the primary tumor, dissolution ○ Abdomen and heart to screen for primary
DISEASE FORMS/SUBTYPES of the basement membrane and invasion sites of disease
• Benign or malignant into the bloodstream, evasion of the host ○ Nodule itself, with aspiration for diagnosis
• Malignant nodules may be metastatic or immunity and survival in the bloodstream, if possible (p. 1113)
primary. margination in a new capillary and attach- • CT to assess for lesions too small to be identi-
Most primary lung neoplasms are adenocarci- ment to the endothelium, dissolution of the fied with plain film radiography and/or to be
nomas (75%) or carcinomas (20%). basement membrane and extravasation into used for CT-guided aspiration or biopsies
the extracellular matrix, survival in the new • Fungal and microbial testing based on clinical
HISTORY, CHIEF COMPLAINT tissue by evading the host immunity, and suspicion and history
• Pulmonary nodules or masses may be induction of neovascularization to support • Airway lavage sometimes beneficial (pp. 1073
found incidentally in patients undergoing continued growth of the new metastatic and 1074)
radiography for other reasons. focus. Neovascularization begins the process • Thoracotomy with histopathologic evaluation
• When lung neoplasms cause clinical signs, again. of biopsy specimens. The hilar lymph nodes
the most frequent complaints from the owner and lung lobes should be carefully evaluated
are cough and dyspnea. DIAGNOSIS and sampled as necessary.
• Sputum with or without blood or hemoptysis
is possible. Diagnostic Overview TREATMENT
• Other possible signs are weight loss, fever, Recognition of pulmonary nodules is usually
dysphagia, vomiting, regurgitation, and made with a radiographic evaluation. A system- Treatment Overview
wheezing. atic approach is paramount to rule out infec- Goals are resolution of clinical signs and control
• Cats often manifest signs related to metastatic tious or granulomatous causes (as warranted or elimination of primary disease process (excep-
disease to their digits rather than respiratory by geography) or other foci of neoplasia (i.e., tion: clinically unimportant pulmonary nodules
signs. primary lesions elsewhere that have resulted in such as pulmonary osteomas)
the identified pulmonary nodules). • Single pulmonary masses are commonly
PHYSICAL EXAM FINDINGS addressed surgically (focal process).
• Physical exam: often normal Differential Diagnosis • Multiple pulmonary masses typically are part
• If due to metastatic disease: physical abnor- • Solitary lung mass: primary neoplasia, of a generalized process (e.g., neoplastic,
malities from the primary tumor may be metastatic neoplasia, granuloma, cyst, infarct, fungal). Identification of cause and systemic
found in other parts of the body. localized hemorrhage, focal pneumonia, (medical) treatment are most important.
• If due to fungal or other disorder: abnor- abscess
malities related to the lungs (e.g., tachypnea, • Multiple pulmonary masses: primary or Acute General Treatment
crackles) or systemic illness (e.g., fever, metastatic neoplasia, fungal disease (e.g., • Supportive care (p. 1146) may or may not
lymphadenopathy due to systemic mycosis) blastomycosis, histoplasmosis), pulmonary be required.
• Careful evaluation of the common sites of osteomas (rarely > 3-4 mm in diameter and • After a lesion has been identified, surgical
origin for tumors that metastasize to the more radiopaque than soft-tissue nodules excision should be considered.
lungs is indicated (e.g., oral cavity, area of because of mineral composition), eosinophilic ○ Treatment of choice for primary pulmo-
the thyroid, mammary glands). bronchopneumopathy. Bacterial abscesses and nary neoplasia (single pulmonary nodule
• In cats, careful evaluation of each claw granulomas uncommonly cause multiple in which the diagnosis was established
(paying particular attention to the quick) pulmonary masses. with aspiration or biopsy)
and of the fundus is important; both of these • One or more cutaneous or subcutane- • Surgical excision may be considered for soli-
sites are predisposed to primary and second- ous nodules, one or more nipples, and tary pulmonary nodules/masses of unknown
ary metastasis of angioinvasive pulmonary intrahepatic mineralizations can be mistaken tissue type. The slow-growing nature of some
tumors. for focal pulmonary lesions, especially if only single pulmonary nodules means that other
• A rectal exam is essential in every dog with one radiographic projection is made. concerns (e.g., concurrent illnesses, patient
pulmonary nodules (assess prostate, anal age) may supersede the need for thoracotomy.
sacs, bladder/urethra, sublumbar lymph Initial Database • In specific cases, metastasectomy (excision of
nodes). • Thoracic radiographs metastases) can be performed. Consultation
• A fundic exam (p. 1137) and careful ○ Most often source of initial identification with an oncologist is recommended beforehand.
dermatologic evaluation may be helpful in of pulmonary nodules (less commonly
identifying disseminated fungal disease. found at surgery or necropsy) Chronic Treatment
○ Three views should be obtained. • Chemotherapy may be attempted for primary
Etiology and Pathophysiology • Repeated meticulous physical exam (with pulmonary neoplasia deemed unresectable
• The main concern for patients with pul- particular attention to the mammary or with evidence of lymphatic metastasis at
monary nodules is malignancy; neoplasms chains, anal sacs, oral cavity, skin, fundus the time of diagnosis. Options may include
from virtually any part of the body, including and digits) doxorubicin, platinum compounds (cisplatin,
primary lung tumors, may metastasize to the • CBC, serum biochemistry profile, and urinal- carboplatin), gemcitabine, vinorelbine, or
lungs. ysis: typically unremarkable in patients with tyrosine kinase inhibitors.
• Metastatic neoplasia may reach the lungs incidentally discovered pulmonary nodules. • Chemotherapy is largely unproven in the
through lymphatics or the bloodstream; both Hypercalcemia may occur with neoplasia, management of pulmonary tumors in
can produce a nodular pulmonary pattern. fungal, and other granulomatous diseases. veterinary medicine.

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